WO2009145609A1

WO2009145609A1 - Method of and apparatus for generating/processing a spatial-data-change message

Info

Publication number: WO2009145609A1
Application number: PCT/NL2008/050316
Authority: WO
Inventors: Volker Hiestermann
Original assignee: Tele Atlas B.V.
Priority date: 2008-05-27
Filing date: 2008-05-27
Publication date: 2009-12-03

Abstract

A method of generating a map-agnostic spatial-data-change message is disclosed. The method comprises - acquiring an indication of a spatial-data-change; - selecting one or more map elements from a master digital map to be associated with the spatial-data-change to specify the location of the spatial-data-change; - generating an event comprising for each of said one or more map elements a dynamic location reference and a description corresponding to the spatial-data-change; - generating meta data associated with the event; - combining the event and the meta data to obtain the map-agnostic spatial-data-change message. Furthermore, a method of processing a map-agnostic spatial-data-change message is disclosed. The invention enables map-applications to update their application digital map database with data that is coming from different sources and that is based on different master map databases.

Description

Method of and apparatus for generating/processing a spatial-data-change message

Field of the invention

The present invention relates to the field of generating spatial-data-change messages to be transmitted for use in updating or augmenting maps comprised in navigation applications, local search services, web-applications and the like. Furthermore, the invention relates to the field of processing spatial-data-change messages.

The invention further relates to a computer implemented system for generating a spatial-data-change message, a computer implemented system for processing a spatial- data-change message, a spatial-data-change message, a computer program product and a processor readable medium provided with the computer program product.

Background of the invention Digital maps as deployed for navigation applications, local search services and the like are digital data sets stored in some form of database which is accessed by said applications. Such digital maps comprise a static map of a road network with map elements and map properties, and further separate data files comprising map properties that are linked to the map. Digital map data can be provided by many sources, wherein the static map comes from map vendors, such as Tele Atlas. Such vendors go to great lengths to gather new and current information about the spatial world and update their internal map representation ("master DB") to better reflect the current real world. An example of sources that provide digital map data include, local government data sources, aerial imagery, customer feedback, probe data and web applications which make it possible to view/search for particular spatial data which position is linked to an element of the static map used by said web application. Examples of spatial data are POI, pictures, descriptions of buildings, personal information of a person linked to his address to be shared in a community, and static map data such as roads, road attributes etc. Another example of sources are spatial data services. Existing forms of spatial data services include but are not limited to: Traffic services, which provide real-time traffic information (such as road traffic incidents, current average speeds, and the like) to navigation applications to improve route planning which otherwise relies on static road classifications only.

Map services which provide map update data to amend an application's digital map, either deleting/changing/adding individual map elements or map properties, or replacing greater portions of map coverage (including full internal map replacement).

Map overlay services which customize application map DBs by means of map extensions or sidefiles, including the incorporation of new Points Of Interests (POIs), the collection of personal or shared favorite locations. Map overlay services allow the community to create collectively new domains of map content and the like. A common characteristic of the digital map applications is that each digital map application uses his own reference static map of the road network. Even if static maps are from the same map vendor they may differ in version, and consequently in database content.

There is a need that spatial-data present in one map-application (source application) can be imported in or exported to another application (target application). Due to the different static maps used, a geo-position of a particular geo -position in the static map of the source map -application could differ significantly from geo-position of the same road in the target map-application. Just copying the spatial data from the source map-application to the digital map of the target map-application could result in an incorrect linking of the spatial data with the static map of the target digital map. Furthermore, spatial data in the source map-application may be linked to a database structure which does not exist in the target map-application, while the real- world object related to said database structure is described in both digital map databases.

Summary of the invention

The present invention seeks to provide a method of generating a map-agnostic spatial-data-change message, that could be processed, evaluated by any application and, if applicable, applied in the digital map, that is any application comprising any version of a digital map from any vendor of digital map databases or any spatial content provider, and a method to process such a map-agnostic spatial-data-change message. The invention provides a method of publishing and processing individual spatial-data- change messages independently from prior knowledge of targeted map version and map -internal object references.

According to the invention, the method comprises: - acquiring an indication of a spatial-data-change;

- selecting one or more map elements from a master digital map to be associated with the indicated spatial-data-change to specify the location of the change;

- generating an event comprising a dynamic location reference for said one or more map elements and a description corresponding to the indicated spatial-data-change; - generating meta data associated with the event;

- combining the event and the meta data to obtain the spatial-data-change message.

The invention is based on the recognition that a multitude of digital map databases that could be used as reference database, i.e. master digital map database from different map-vendors, are available. The digital map databases are produced from different sources and generated by different tools, by applying different quality rules etc. Furthermore, different map application providers use different database structures to describe the digital map. A map entity such as a road element in a digital map database could have a different position and different map element properties (i.e. real-world properties differently translated into database properties) in another digital map database. Using different sources and different tools could result in relative and/or absolute position differences, wherein the same object in reality could be, e.g. 0.01 - 60 meters away in the coordinate reference system associated with the different databases. Furthermore, the currentness of the digital map databases could differ significantly. This all results to the insight that a spatial-data-change defined in terms of attributes and coordinates of the respective databases will differ significantly.

Therefore, according to the invention a spatial-data-change message structure is defined which enables us to generate map-agnostic spatial-data-change messages which could be offered to any end user application, wherein each end user application can select to apply those spatial-data-change messages that make sense for its digital map database. Spatial-data-change in the present application means a change in content of an application digital map database when the content of a spatial-data-change message is applied. A spatial-data-change could relate to any map-element, map-property or attribute or data content that is linked to a digital map. Map-agnostic means that the spatial-data-change allows us to target any map, regardless of the current version of the application map, regardless of the vendor of the application map and regardless of who supplied the spatial-data-change message. Furthermore, version-agnostic, a subset of map-agnostic, means that a spatial-data-change message derived from a particular version of a digital map from a map vendor could be used to change, update or even incrementally update the spatial-data of, or linked to any, i.e. older, newer or similar, version of, digital maps from said map vendor used by map applications. Furthermore, map-agnostic means that the spatial-data-change allows one to target application map DBs that are composed as a "patchwork" of datasets or tiles from different map database vendors, and/or of datasets or tiles representing different versions of the digital map. Furthermore, map-agnostic means that the spatial-data-change allows one to target application maps that have continually incorporated spatial-data-change messages over time and thus have evolved from a regular version of an application map database towards an individually customized version of an application map database

A spatial-data-change message with a map-agnostic data structure provides possibilities for update or augment of provisions which are not limited to (proprietary) sources tied to a map vendor and/or map application provider, but also the possibility to submit spatial-data in a spatial-data-change message to any digital map application to update/enhance its application map database with the spatial data. The digital map associated with a digital map application to which a spatial-data-change message could be applied will be referred to as application database (ADB) or application digital map. As the same object in reality could have different geo-positions in the master DB and application DBs, a solution has to be found to find the objects in the application database. This solution is found by using a dynamic location reference in the spatial- data-change message to identify the location associated with an event.

A dynamic location reference (DLR) is a means for accurately matching a location between dissimilar digital maps. This means that a DLR is map-agnostic as it enables a software program to find in two different map -databases the same real- world object. An example of a map-agnostic dynamic location referencing method is ISO17572-3, also known as the AGORA-C method. Use of a dynamic location referencing method entails encoding and decoding steps. A DLR encoder, e.g. AGORA-C encoder, deployed by a first application, composes a compact geo reference, DLR, from a variety of map elements, applying a standardized encoding algorithm. A DLR is a special-purpose micro map of an object which is transformed into a compact physical expression (such as a binary string, or an XML document). A DLR decoder, e.g. AGORA-C decoder, deployed by a second application, decomposes the physical expression and interprets the encoded information on the basis of the application map. The DLR decoder anticipates dynamically on map differences at the time of decoding. Decoder operation includes the cases of determining (a) that all parts of a location reference exist in the application map (full match); (b) that all parts of a location reference are absent in the application map (no applicable match); and

(c) that certain parts of a location reference exist in the application map while all others are absent (partial match).

A DLR is generated by using a variety of map characteristics depending on local conditions. These characteristics include coordinates, object type, angles, distances, names, and any other map descriptor. A DLR comprises sufficiently redundant information to aid in validating a correct match in an application map database.

On decoding, the original ingredients of a DLR, such as coordinates or parts of a street name retrieved from the source map used by the encoder, are superseded by corresponding information as they are present in the application map used for decoding and matched to the DLR. This means that the decoding application will use the decoding result in terms of local map characteristic (i.e., local coordinates, local name, spellings, local road attributes, etc.) rather then the original map characteristics conveyed via the DLR. In other words, the decoding action "transforms" the original encoded information into the terminology of the application map; it "matches" the original geometry to the geometry of the application map; it "matches" the original attributes; and it "translates" the original spelling of the name string into the corresponding names in the application map. For instance, the application map may use abbreviations or only upper case characters as opposed to the original spelling which used mixed case characters.

The DLR provides semantic interoperability between digital maps. Semantic interoperability is "the ability of two or more computer systems to exchange information between a transmitting system and a receiving system and have the meaning of that information accurately and automatically interpreted by the receiving system". By using a DLR to address a location of an object associated with a spatial- data-change, i.e. the corresponding location, if the object exists in the targeted application digital map, can be found.

In summary, a map -agnostic description will be generated corresponding to the spatial-data, comprising information about the spatial-data at hand, including its location (in terms of a DLR). Furthermore, the meta-data associated with the event is added to further aid in evaluating the relevance of the event for a particular map application.

The method according to the invention combines the best of two worlds, dynamic integration of spatial data (using a map-agnostic location referencing) and comprehensively described events, which classifies and qualifies the spatial-data and/or changes thereto. The event is supplemented with meta data to improve the classification and qualification process in an application processing the spatial-data- change message. As a result, the method according to the invention creates a playing field for multi-source spatial-data interchange by means of interoperable spatial-data- change messages.

In an embodiment of the invention, the DLRs are generated from the content of the first digital map prior to the change. This embodiment is advantageous for distributing a change in subsequent versions of a map database to an application map database and increases the possibility to find a match in the targeted application database maps.

In another embodiment of the invention, the event comprises a description of the changed properties of the state of reality prior to the change and a description of the state of reality after the change. These features enable an application to verify whether the event is already applied, or partially applied, to the digital map and provides information to roll back an executed spatial-data-change message.

It is an object of the invention to provide a "decoding" method which utilizes the features of the spatial-data-change message generated by the "encoding" method according to the invention. Processing the features of the spatial-data-change message enables the user of the invention to resolve potential conflicts between the spatial-data- change message corresponding to the event and the local scope of the targeted application map database. The available features, attributes present in a map define the local scope of an application map database. The method according to the invention comprises: - acquiring a spatial-data-change message;

- retrieving the event and associated meta data from the spatial-data-change message;

- retrieving a dynamic location reference from the event;

- evaluating the relevance of the event for the application map comprising the action decoding the dynamic location reference to find a match in the digital map; - if relevant, applying the spatial-data-change to the digital map in dependence of the relevance of the event for the application DB.

These features enable an application to verify the relevance of the spatial-data prior to applying the spatial-data-change directly. The act of applying the spatial-data- change may comprise any appropriate technique of making the change information accessible to the map application, including appending the application map database, overriding or deleting data structures in the application map database, creating and maintaining an overlay layer, etc. The method performs a pre-filtering in order to resolve potential conflicts between the spatial-data content and the corresponding content in the application database. The achievable degree of successful resolution of spatial-data-changes by a map application depends on the nature and the functionality of the map application, the content and structure of the map database, and the variety and quality of the spatial-data source and spatial-data-change message publisher. The relevance of the event described by the spatial-data-change message could be derived from the attributes describing the event and/or the meta data. In an embodiment of the method of processing a spatial-data-change message, the relevance is derived by using a decision graph of logical evaluations, wherein for each decision at least two outcomes are possible, of which at least one outcome triggers a trivial action, wherein a trivial action is an action that is directly executable and is selected from a group comprising at least two of: continued with next evaluation step, executed map updating action corresponding to event, event not applicable, event reevaluated when causal condition is met, event is obsolete. These features offers a step-by-step break-down of the complexity of the decision to separate trivial cases from non-trivial ones and to ultimately translate non-trivial actions into trivial actions, which can be directly executed.

It is an object of the invention to provide a method which enables a computer implemented system to generate a map-agnostic spatial-data-change message and a computer implemented system, such as a server, navigation device, PDA, and other mobile devices, to perform only relevant spatial-data-change messages and in a reliable way, on its associated map database.

It is acknowledged that a dedicated map updating/upgrading process, in terms of a proprietary process controlled by a map vendor and/or map application provider as a single source, offers higher confidence in the continuous integrity and consistent currency of the local digital maps in map applications. At the same time, update/upgrade accessibility (both in terms of time and content) is at the discretion of the single source. However, it is a high burden for a single source, compared to multi- sources, to act as aggregator for an equally broad variety of update sources and update/upgrade content. The ability to use spatial-data-change messages from multiple sources enables a map application to receive update/augment information regarding particular spatial-data from the best data source and to take the consequences of the spatial-data into account when performing a query on the application map database, i.e. to plan a route, find a point of interest POI and the like. The best data source could be the most up-to-date one, the most accurate one, the most detailed one, the most favorable one, etc.

Short description of drawings

The present invention will be discussed in more detail below, using a number of exemplary embodiments, with reference to the attached drawings, in which

Fig. 1 shows a spatial-data-change message generation flow;

Fig. 2 shows a spatial-data-change message processing flow;

Fig. 3 shows a flow diagram of a spatial-data-change message generation process;

Fig. 4 shows a flow diagram of a spatial-data-change message application process;

Fig. 5 is a block diagram of an exemplar computer system for implementing the method according to the invention; Fig. 6 shows schematically the data structure of a spatial-data-change message according to the invention; and

Fig. 7 shows a simplified example of a decision graph applied on a spatial-data- change message.

Detailed description of exemplary embodiments

Figure 1 shows a general overview of the spatial-data-change message generation flow. The system 100 generating a spatial-data-change message is arranged to receive an input signal indicating a spatial-data-change. A spatial-data-change could correspond to a change in reality, an map entity or attribute of the master database to be distributed to application databases, content to augment the content of application databases. The indication of a spatial-data-change initiates the process to generate a spatial-data-change message. The spatial-data-change indication could be generated in response to a map application user requesting a spatial content provider to submit particular spatial content from its database to the users map application database. The spatial-data-change message is intended to make a map-application using a map- database aware of a possibility to improve its map-database with the content corresponding to the spatial-data-change indication. The improvement can be a map- update corresponding to a change in reality, such a new road to be added, changed road, closed road, name change, etc, or augmentation of the map-database with new content, which was previously not available in the application map-database or updates/changes to the content of the map-database.

The spatial-data-change indication could also be generated automatically by the software program of a content provider as soon as a change is made in its own map- database to make the change available for other map applications, even if the map applications use a map from different map-vendors or other (older or newer) versions of the static map used by the content provider. This possibility enables us to provide map-services which a user can subscribe to, to keep the content of its application map database up-to-date. In view of the above, a spatial-data-change indication can be obtained from different sources 102, 104, 106, 108. The system 100 could be in the form of a computer arrangement or computer implemented system as shown in figure 5. A spatial-data-change could relate to any change that could be incorporated in a digital map database. In the context of the present invention a digital map database could be any possible combination of data structures to describe a road network topology and content which is linked to entities of the network topology. Data structures that could be used are relational or hierarchical database structures, tables, files, etc. The road network topology is considered to comprise static data, as these database elements will hardly change. The static data comprises the basic information to plan a route from A - B and to provide a brief description of said route. The database content linked to the network topology, i.e. static data, is regarded to describe dynamic content of the digital map database. The dynamic content could be stored in dynamic layers, tables and/or files associated with but to the "side" of the map, i.e. network topology, itself. A spatial-change could relate to: a new road, (temporary) closing of roads, a change in position of a road, change in street name, housing information and the like, addition of new searchable features like POIs linked to a map database (e.g. restaurants, hotels, gas stations, public toilets, etc), change in coordinates of any feature, speed limit changes, change in road numbering, change in properties of a road (one-way street, type of road, form of way), turn restrictions, administrative and postal boundaries, water features, land use features and the like. The different sources 102, 104, 106 and 108 generate information that is an indication of a spatial-data-change. The indication could be in any suitable format sufficient to describe for which spatial data a spatial-data-change message has to be generated. For example, the indication could be an input signal indicating that a POI or any other content to augment a digital map having an association with a location in the master database has to be made available for or distributed to other application databases. A spatial-data-change could relate to one or more attributes of a map element, being stored in the map, in overlay layers, or in sidefiles, and wherein such one or more attributes may change rarely, frequently, or constantly.

A spatial-data-change indication corresponding to a change in reality could be acquired by system 100 via a web-application running on a computer network. The web application enables a user to select which spatial-data present in the map database associated with the web-application should be distributed to a user's map application, for example a navigation device of the user. This possibility enables a user to update/upgrade/augment his map database with spatial content that is present in other map databases.

A spatial-data-change indication could also be initiated by a Department of Transport (DoT) by a person 104 who inputs changes in reality by hand into the system 100 with the corresponding coordinates in a coordinate reference system. The person 104 could also be the vendor or manufacturer of the master DB who indicates that specific attributes of the master database, for example a category of POIs, should be selected from the master database and offered to other map applications to enhance/augment the content of their internal application digital map database. These indications could result in a change of static map-objects as well as dynamic attributes of application digital map databases.

Another possibility to acquire a spatial-data-change indication is indicated by 106 wherein on a public or private web application, a user could click on a particular entity from a map on a screen. The application then provides the possibility to amend the properties of said entity or add a new feature/property to said entity or location corresponding to said entity.

So-called Map overlay services enables customization by means of map extensions, including incorporation of new POIs, the collection of personal or shared favorite locations or the like. This provides a community approach for collectively creating new domains of map content and to provide new dynamic map content associated with static map elements. A user can subscribe to such service and receive the new map content or changes in map content automatically. In this example a spatial-data-change indication will be sent automatically as long as a user is subscribed to the update service and a change is made in the spatial-content the user has subscribed to.

Furthermore, spatial-data-change indications could be received by means of Object records 108 that could be generated locally by for example a map supplier or content provider and stored on a record carrier. Each object record 108 comprises a description of spatial data to be distributed and a predefined link to the master database to define the position of the spatial data. The predefined link is a unique reference to a map-element of the master database. Unique means that the reference can only be used to link to the master database associated with the system 100 and not to another database. An example of providing a unique reference is using a look-up table to define the link between the spatial-data and the master database. The system 100 is then arranged to read the object records 108 from the record carrier and to perform batch processing on the object records and to generate the corresponding spatial-data- change messages.

Characteristics of the input data described above is that they all describe a spatial- data change in terms of a location and data describing the spatial-data associated with said location. The location could be specified in a code identifying a location in a road network (e.g. RDS-TMC), in coordinates of a coordinate reference system (WGS84, EGM96, NAD83, or the like), other coordinates of a digital map such as coordinate projections or dedicated link to an entity of the master database. Optionally, the date and/or time of change and period could be also given for a spatial-data-change. This could be advantageous when the spatial-data-change relates to a change in reality, for example a road closure due to planned road constructions. In the present description, each individual spatial-data-change indication will be identified as an event. Thus according to the invention, an event relates to one spatial- data-change. In the following description for each individual event that could result in a change in the content of a digital map database, a spatial-data-change message will be generated. Consequently, the generated map-agnostic spatial-data-change message will be short and could be distributed at any time without occupying the communication channel for a long period. It should be noted that the present invention is not limited to generate a spatial-data-change message which includes data related to one spatial-data- change and could also be used to generate a spatial-data-change message which includes more than one changes in reality. After receiving the input data indicative of a spatial-data-change , a spatial-data- change message generation application 110 running on the processor of the system 100 will acquire an indication that there is a spatial-data-change, i.e. an event. The system 100 comprises further a digital map database 112, i.e. master database, comprising at least the description of a road network in terms of map elements and map properties. A map element is an entity of the map database such as a road element or part of it, in terms of a linear section of geometry, an intersection in terms of a node, or an area object. A map property is a property or attribute linked to any of the before-mentioned map elements or a relationship between map elements. A map property can be a property in a map DB or a property that is associated to said map DB but in a side file or the like.

Subsequently, the spatial-data-change message generation application 110 selects one or more map elements from the digital map that could be associated with the spatial-data-change to specify the location of the spatial-data-change indication and consequently the reference location of the corresponding spatial-data-change to be applied in an application DB. Then the application generates for the selected map elements a DLR. A DLR could refer to different categories of locations, namely

- point locations, such as a geographic landmark near a road way or the location of a pedestrian crossing;

- linear location, such as a stretch or roadway or a certain path through an intersection; and - area locations, such as a dedicated zone (e.g. congestion charge) or the area affected by a weather condition, either in terms of concatenated linear locations representing the area's outline (explicit composition) or by means of a set of point/linear/area locations contained within the area in question (implicit composition).

As explained above, a DLR provides semantic interoperability between different digital maps. The digital maps may differ in terms of the network topology, map attributes as well as used internal data structure. By means of a DLR a location/position associated with a map-element in a master database could be found or identified in an application database if the corresponding map-element is present in the application database. By means of the DLR a universal description is made for the location of the spatial-data-change. Furthermore, the spatial-data-change message generation application 110 generates for the spatial-data-change indication a description which when applied to a digital map database will result in a change in the content of the digital map database. For example, a road closure or blocked road could be described by DLRs corresponding to the road segment being closed/blocked and a property indicating that the road segment cannot be used for travelling. A new road could be described by generating DLRs for the begin and end location where the new road is connected to the existing road network, an indication that the spatial-data-change relates to one or more new map-elements and a description of the new map-elements describing the new road. The combination of DLR and description of the spatial-data- change form an event. Furthermore, the spatial-data-change message generation application 110 generates meta data associated with the event to enable a digital map application receiving the spatial-data-change message to evaluate the relevance of the event for its digital map. The meta data could for example identify the date of generating the spatial-data-change message, the source of the input data causing the generation of the spatial-data-change message, the used digital map to generate the DLR, a sequence number, the type of update etc.

The event and meta data are linked together and could by published by broadcasting the spatial-data-change message via a radio network, telephone network, computer network or cable network 114. In an embodiment the spatial-data-change message is distributed via the internet 116 or stored as a spatial-data-change record or message in a data storage 118 such as a hard disc that might be accessible via the internet or a portable memory device, such as a memory card, USB-memory card, or the like. In another embodiment the spatial-data-change message is rendered as a graphical barcode or semacode structure 120 or any other computer readable form when the spatial-data-change message is printed, and stored and/or distributed in print form, or PDF format.

It should be noted that any supplier of spatial-data-change messages according to the invention uses a system 100 as shown in figure 1. Each supplier will use his own preferred master database. Therefore, an indication of a spatial-data-change from one source could result into more than one spatial-data-change message each from a different supplier of spatial-data-change messages. Each of the spatial-data-change messages will have a DLR which is derived from the suppliers preferred master database. Thus a spatial-data-change message related to the same spatial-data but from different suppliers will normally have different DLRs. The different DLRs will address the same real- world location, but with different spatial positions and potentially with different map-elements and/or map-attributes. The system 100 transmits the spatial-data-change message to receiving applications. The transmission includes protocols for push and/or pull delivery. The system 100 publishes a spatial-data-change message with at least a minimum set of meta information, which could include data about identification, non-spatial behaviour, publisher, and dependencies to/from other spatial-data-change messages. The amount and kind of meta data accompanying a spatial-data-change may differ depending on the nature of the spatial-data-change at hand (e.g. whether the spatial-data-change addresses a single speed limit change; a combined spatial-data-change of a number of individual ones; or a spatial-data-change dependent on other spatial-data-change messages; or whether the spatial-data-change message introduces a change to a map vs a spatial-data-change cancelling said change after its duration has expired). The amount of meta data may further depend on the transmission medium and/or protocol. The amount of meta data may further be governed by the subscription level available to or arranged by the user. For example, the invention may be applied for free-of charge spatial-data-changes, dedicated user community oriented spatial-data-changes, and comprehensive payable spatial-data-changes, e.g. by means of a service similar to current SMS -services to download ring tones. By sending an SMS with a code to the service spatial-data to be sent can be selected and a corresponding spatial-data-change message will be sent back. A spatial-data-change message according to the invention complies with the following characteristics:

A) is expressed in terms of a generic, map-agnostic description of the actual spatial- data-change;

B) is uniquely identifiable; C) may be published at any time, as appropriate, to announce, confirm, cancel, or otherwise communicate about a spatial-data-change;

D) uses a map-agnostic dynamic location referencing method to localize the spatial- data-change, making the spatial-data-change message generally applicable and independent of an applications map version and supplier; E) includes information about the non-spatial behaviour of the spatial-data-change, for example when, and optionally the expected duration, a qualification of the duration, i.e. whether the change is estimated, scheduled, etc, and the like; Optionally, a spatial-data-change message may:

F) classify whether it provides an independent (new) geographic phenomenon or property, whether it changes a static geographic phenomenon or property, whether it terminates a geographic phenomenon or property, or whether it "flags" a geographic phenomenon or property as being subject to (unspecified) changes, for instance for addressing large scale reconstruction work in progress, traffic flow redirected or closed during seasonal events, or the like;

G) indicate an override to one or more geographic phenomena or properties in an application's local map; H) describe multiple changes in reality;

I) relate to another spatial-data-change message or set of spatial-data-change messages, whereby the relation(s) could be classified as a dependency, a sequence, a choice or the like; related spatial-data-change messages may be provided as a group or individually, in the latter case using a means of referencing to other related spatial-data-change messages.

J) include a proprietary reference to the geographic phenomenon or property affected by the spatial-data-change, such as a map element identifier, an official road furniture identifier, and the like; K) include a classification identifying the credibility of a spatial-data-change message (or its cancellation, change of state, or the like), in order to allow resolution of non- trivial constellations in case of incomplete, overlapping, inconsistent, contradicting, or otherwise unclear co-existence of spatial-data-change messages made available to a spatial-data-change message application, wherein the classification could identify whether the spatial-data-change has been field- verified, results from journalistic investigation, results from combining partial sources, results from third party reports, results from a community effort, results from own changes, or the like.

The use of a spatial-data-change message according to the invention is not constrained by the master digital map database used during generation of the spatial- data-change message. The spatial-data-change message according to the invention could be used to publish road safety attributes for use by navigation applications. In an embodiment, a public road authority managing the road network for a given coverage area could publish spatial-data-changes for attributes like local speed limits, lanes closures, speed recommendation based on weather forecasts and changes thereto, for the said road network (or parts thereof) via on-line channels, enabling a navigation application to take into account the corresponding effect related to planned trip and to calculate an alternative route.

Furthermore, a map-agnostic spatial-data-change message according to the invention could be used to provide incremental update(s) from a map vendor's master database to any version of application map databases from the same map vendor. In this context map-agnostic means version-agnostic and map in "map-agnostic" should also be interpreted as different versions of application map databases from the same map vendor.

A spatial-data-change message according to the invention has a general scope, in terms of the described event, which reflects whether in reality a geographic phenomenon was added, deleted, or a property of said phenomenon was changed. This general scope may or may not correspond to the local scope, in terms of the event's local interpretation by a navigation application. As an example, a blocked road being published as a change to the road network may not be a change in a local application map database due to a more recent map or a previously received spatial-data-change message reporting the same change. A more detailed description of an embodiment of the method to generate a map-agnostic spatial-data-change message will be given below.

Figure 2 shows a spatial-data-change message processing flow. A generated spatial-data-change message could be processed by any system 200 running a digital map application, such as a navigation device, navigation application running on a web server, web-application providing searching facilities wherein associations to a map database are taken into account. An update application 202 for processing the spatial- data-change message is running on a processor present in the system 200. The spatial- data-change message could be supplied to the update application in various ways. The spatial-data-change message could be published by broadcasting the spatial-data- change message via a radio network, telephone network, computer network or cable network 114. In an embodiment the spatial-data-change message is distributed via the internet 116 or stored as a spatial-data-change record or message in a data storage 118 such as a hard disc that might be accessible via the internet or a portable memory device, such as a memory card, DVD, CD or USB-memory card 210. In another embodiment the spatial-data-change message is made available in terms of a barcode or semacode 120 in print form, or as PDF or any other printable document that could be read by a processor.

The update application 202 acquires a spatial-data-change message via any of the distribution channels 114, 116, 118, 210, 120 described above. Subsequently the application retrieves from the spatial-data-change message the event and the meta data associated with the event and from the event the DLR. By means of a DLR decoder, a location match in the application map stored in the map database 204 is determined. The match could be a full or a partial match. It should be noted that also a partial match could be sufficient to determine uniquely and reliably the location in a digital map database corresponding to the event, enabling one to apply the corresponding spatial-data-change in the digital map database. The metadata and/or description of the event will be evaluated for its relevance with respect to the map application running on the system 200 and the digital map database 204. The evaluation depends on the amount and kind of published meta data and if a partial of full match is found. It also depends on the capabilities of the application system to support or not support certain actions resulting from the local scope of the spatial-data-change message. As an example, an application system may support patching of one-way directions, however it may not support insertion of new or changed road network links & geometry. After the decision that the spatial-data- change falls into the system's functional scope, the spatial-data-change will be applied to the map in the application map database 204. Figure 3 shows a flow diagram of an embodiment of a spatial-data-change message generation process. The method starts with step 302 in which an indication of a spatial-data-change is acquired. The indication could be received on request by the application performing the process or received automatically by the application, which subsequently triggers the process to generate a spatial-data-change message. As said before in figure 1, the indication could be generated by different sources 102, 104, 106, 108. The indication could result into one or more spatial-data-change messages. The indication comprises a source dependent description of where the spatial-data-change is and what the spatial-data-change is in the context of the master map database used for generating the spatial-data-change message. The spatial-data-change could correspond to previously applied change in the master database, but could also correspond the spatial-content of the master database which will result in a spatial-data- change when applied to a receiving application database. For example, if the indication relates to the transmission a spatial-content, such as a POI of the master database, the indication identifies specific POI and as the POI is already linked to the map of the master database, a reference to the POI implicitly identifies the location in the master database. Furthermore, if the indication relates to a change in the master database, the database entity being changed has a description and a location. Another example is the change of road attributes, such as the speed limit or the one-way direction. A map vendor which is periodically surveying the road network for collecting road network changes would serve as either source 104 or 106 and identify individual spatial-data- change corresponding to changes in reality in the context of the map vendor's master database. Optionally, the indication comprises data related to when the change is or will be. However, the acquiring time of the indication by the process could be used as a time stamp, to be included in the spatial-data-change message to provide an approximate estimate of the time of the spatial-data-change.

In step 304, the "where" part of the indication is used to select map elements from the master digital map database accessible by the process. For example, if the spatial-data-change is a change of a street name, then the map element corresponding to said street has to be selected from the master digital map. However, if the change is related to a new road, which result in new map elements to be added to both the master database and application database, then at least two map elements have to be selected, one related to the beginning of said road and one to the end of the road. Preferably, the map elements are selected from the digital map prior to the spatial-data-change. The chance to find a match in an application database will be higher if the content of the master database prior to the spatial-data-change is used. If only new map elements are used, it will not be possible to find a full match, as the added map element is likely not to be present in the application database before.

In step 306, a DLR is generated for each of the selected map elements. The DLR will be used to provide a map-agnostic description of a location associated with the spatial-data-change. The DLR provides a spatial footprint for the receiving application to determine "where" a spatial-data-change occurs.

Next in step 308, a description is made of the spatial-data-change. The description describes "what" has to be changed by the spatial-data-change message and could relate to map elements and map properties. A map element could be an entity of the master digital map selected from the group comprising at least some of: road element, linear section, intersection, point object, explicit area object, implicit area object (in terms of the contained map elements). A map property describes an attribute linked to a map element or a relationship with the map element or between map elements. A map property could be any attribute selected from a group comprising at least some of the following items: street name, house number, number of lanes, functional road class, turn restrictions between two road elements, intersection type, driving direction, connection angle, form of way, point distance, curve radius, contour line height, POI, email address, etc. If the spatial-data-change relates to a change in the master database, the description describes the scope of the indicated spatial-data-change and comprises at least the data describing the reality in terms of concerned map elements and/or map properties after the change and optionally the concerned map elements and/or map properties before the change and the type of change. Furthermore, the description could comprise information about for example: the date of spatial-change, the duration of a road closure, etc. The type of change can be one of: delete, replace, insert, modify and any other database operation.

The description could be in any appropriate data structure, for example a standardized GDF (ISO 14825 Geographic Data Files) like structure or XML document. The description could use a DLR to describe the geometry of a spatial-data-change when the change corresponds to a change in reality. The DLR as part of the description provides a part of rendering the look and feel of a new part of the road network, e.g. a road section, to be added to a map. The one or more DLR generated for the spatial- data-change and the description are linked together to obtain a data structure which will constitute an event. An event is a map-agnostic semantic interoperable description of a spatial-data-change which could be an actual change in reality. If the spatial-data-change indication is used to initiate distribution of content of the master database or content linked to geo-graphic positions, the description describes the scope of the indicated spatial-data-change (i.e. spatial database content) and comprises at least the data describing the content of or data linked to the master database to be distributed in terms of concerned map elements and/or map properties.

In step 310, meta data is generated for the spatial-data-change message. The meta data could be any of the information about the event to be included in the spatial- data-change message. The meta data is everything that is not describing the spatial- data-change, i.e. the event itself. Some examples of meta data are the publisher of the spatial-data-change message, reference to the master digital map used to generate the DLR, version number, sequence number in case one spatial-data-change indication results in a sequence of spatial-data-change messages, each comprising one or at least a very limited number of changes, link to spatial-data-change message that has to be performed before or together with current spatial-data-change message, credibility level of the spatial-data-change message, generation or publishing date of map up-date message, etc. The meta data enables a digital map application to evaluate the relevance of the spatial-data-change described by the event for its local digital map. Furthermore, the meta data provides a unique identification for the spatial-data-change message comprising one or more attributes selected from a group comprising: publisher name, serial number, edition number, time of publishing spatial-data-change message, source providing change, credibility level.

In an embodiment, in step 310 a parameter which characterizes the nature of the spatial-data-change message is generated. The parameter could be one selected from a group of categories comprising: independent (new) map element and/or property, changed map element and/or property, deleted map element and/or property, map element or property flagged for (unspecified) changes (for instance for addressing large scale reconstruction work in progress, traffic flow redirected or closed during seasonal events, or the like). The parameter is very suitable to determine with easy decisions the relevance of the spatial-data-change described in the spatial-data-change message for an application and it associated map database.

Finally, in step 312, both the meta data and the event are linked together and stored in as a computer readable digital data structure as a spatial-data-change record or message on a storage medium, such as a memory, USB stick, DVD-disc and the like, or transmitted/broadcast via the ether or internet, or printed on a surface e.g. as a semacode or barcode. The event and meta data could also be placed on the internet on a web server, where users can download the map-agnostic spatial-data-change message. Figure 3 suggests that the individual steps have to be executed in a subsequent predefined order. It should be noted that the invention is not limited to this order. For example, steps 306, 308 and 310 can be executed in parallel. Step 310 can be executed immediately after step 302. In general, each step can be executed as soon as the necessary input data is available. Step 306 can only be executed after map elements are selected in action 304.

It should further be noted that step 304 and 306 could be performed by a remote web service. The web service provides on request a DLR for a geographic location or geographic phenomenon, wherein the DLR is based on the digital map database accessible by the remote web service. In that case, the process sends a request for DLR to the remote web service and receives the corresponding DLR.

It should further be noted that the present invention could also be used to distribute user selectable parts of a map database, for example an update wherein numerous map entities and corresponding map properties will be added/delete/modified. In that case, for each individual spatial-data-change a spatial- data-change message will be generated with the steps described above. The sequence order of the individual changes will be determined. Then in dependence of the sequence order, the spatial-data-change messages will be generated. In that case, in step 310 one or more parameters will be generated identifying the large spatial-data- change and the sequence number in the sequence of spatial-data-change messages. In another embodiment, meta data will be generating identifying which spatial-data- change has to be performed before the current spatial-data-change can be applied. Optionally, the meta data comprises a reference or link to the previous and or subsequent map -update message.

It could also be possible, that an acquired spatial-data-change indication for generating a spatial-data-change message is due to or depends on, i.e. has a predetermined relationship with, a previously generated spatial-data-change message and can thus be seen as a subsequent edition of a previously generated spatial-data- change message. For example, the predetermined relationship is that both the new spatial-data-change and previous spatial-data-change message relate to the same object in the map database, thus having the same location. In that case, in step 310 meta data is generated conveying information related to the intension of the spatial-data-change message. An intension can be one selected from a group comprising: cancellation of a previous spatial-data-change message, expiration of a previous spatial-data-change message, continuation of a previous spatial-data-change message, change status of a previous spatial-data-change message into unknown/uncertain, change in estimation of an applicable duration of a previous spatial-data-change message, change in credibility, change in provided level of detail of a previous spatial-data-change message, etc. The indication of the intension provides a means to send very compact spatial-data-change messages that enables a receiving apparatus to use data from events from previously acquired spatial-data-change messages, without transmitting all data related to the event. Figure 6 shows schematically the data structure of a spatial-data-change message

600 according to the invention. The spatial-data-change message comprises an event 602 and meta data 610. The event 602 describes a spatial-data-change, i.e. change or changes to be made in an application map database and the meta data 610 provides information enabling an application comprising a digital map to evaluate the relevance of the event for its digital map. The event comprises a description of the spatial-data- change 604 , describing the "what" of the event and one or more DLRs 606 identifying the "where" of the event. Preferably, if the spatial-data-change message relates to an actual change in the master map database, the one or more DLRs 606 are based on map elements and/or map properties of the digital map database prior to the actual spatial- data-change. Optionally, the event comprises one or more DLRs 608 based on the digital map after the spatial-data-change. Having both present enables to improve the change of a correct match. For example, the spatial-data-change relates to the addition of a new road with street name. If the map already comprises the road, the old DLR 606 could result in a match and the new road will be added to the digital map. However, as the road is already present which could be with other coordinates due to another data source, the new road will be introduced twice. By having the new DLR 608, the existence of the road can be verified and the second addition of said road can be prevented. Next, in dependence of the credibility of the spatial-data-change message, the properties associated with the road could be updated if necessary.

The meta data 610 could comprise relational information 612, identifying the relationship of the spatial-data-change message with other spatial-data-change messages. The relational information could specify that the spatial-data-change may only be executed after another spatial-data-change has been applied to the application digital map. In case the spatial-data-change message is one of a sequence of spatial- data-change messages, the relational information could also specify the sequence number of the spatial-data-change message in said sequence. Related spatial-data- change messages may be provided as a group or individually, in a sequence or randomly.

Figure 4 shows a flow diagram of a spatial-data-change message application process. The spatial-data-change message application process is a process running on a navigation device or any system with software the uses a digital map database. By means of the spatial-data-change message application process, the content of the digital map database can be modified with content in a reliable and consistent manner. It should be noted that the addition/removal/amendment of side files and overlays and the like associated with a digital map database are considered modifications or changes of the content of the digital map database. In step 402, the process acquires one or more spatial-data-change messages by means of the ways described above in relation to figure 2. A spatial-data-change message could be acquired by broadcast 114, internet 116, any processor readable medium 210, such as USB stick, DVD-disk, or processing of a semacode or barcode 120. A spatial-data-change message could also be obtained by means of an SMS service, wherein by sending an SMS to a service, will provide on response a spatial- data-change message, that can be processed by the spatial-data-change message application process. Other wireless communications protocols could be used to acquire the one or more spatial-data-change messages.

Then in step 404, the event data and the meta data are retrieved from the spatial- data-change message. And in step 406, the one or more DLRs are retrieved from the invent. Then in step 408 the relevance of the event described in the spatial-data-change message for the map associated with the spatial-data-change message application is evaluated. This step includes the sub step 410 decoding the one or more DLRs associated with the event. This step 410 provides an indication indicating for a DLR whether there was a full match, no applicable match or a partial match, which means that the existence of the location specified by the DLR could be determined with reasonable certainty and said location (except if no applicable match) can be found in the digital map and the corresponding location in the digital map will be given. This indication is a measure to determine the relevance of the event or spatial-data-change. Furthermore, the meta data of the spatial-data-change message is used to evaluate the relevance of the spatial-data-change for the present application. The relevance could further be determined by the attributes of the event describing the spatial-data- change. Furthermore, the application could be arranged to process spatial-data-change messages once a day or once a week. In that case the system receives a multitude of spatial-data-change messages, which could be from different sources while addressing the same event. In that case, the relevance of the spatial-data-change message in relation to the other spatial-data-change messages has to be determined. If the spatial- data-changes are not performed in the correct order, inconsistency with the reality could occur. The meta data enables evaluating the relevance of a spatial-data-change with respect to other received spatial-data-change messages and the relevance with respect to the map-application.

The evaluation may include, but is not limited to, one or several of the following sub-steps, each one or multiple times, in this order or a modified order:

1. prioritization - selective use or dismissal of a spatial-data-change, and ranking relative to others, using individual event-specific information element(s), or meta data elements, or a combination;

2. spatial relevance - applicability of spatial-data-change with respect to the map coverage and/or the local position of the second system, using inclusion/exclusion criteria such as a bounding box, spatial containment, geometrical proximity, topological proximity, and the like;

3. thematic relevance - applicability of spatial-data-change with respect to the map content and supported application functions of the second system, determined by the spatial-data-change's semantic and thematic scope (for instance, a closed motorway not being relevant for a pedestrian navigation application, and an added airport POI not being relevant for a fleet management application);

4. functional relevance - impact of spatial-data-change on application functions of the second system, such as routing, map display, address resolution, and the like;

5. temporal relevance - applicability of spatial-data-change with respect to the targeted or effective data state of the second system, comparing the spatial-data- change's actual existence period and its temporal behavior with the applications temporal scope (for instance, support for forecast views instead of real-time only, and interest in medium and long term road works but not in daily events);

6. integrity - recognition of existing interrelation with other spatial-data- change(s), either as explicit relation (given by meta data) or implicit relation (given by non- trivial constellations of co -existing spatial-data-changes which interfere with each other), wherein for non-trivial constellations this comprises retaining or restoring integrity based on characteristics further described below: ranking, common denominator, superset, partial change, best fit, clustering, credibility;

7. location referencing - finding the corresponding map element(s), or their full or partial absence; 8. event property matching - finding the corresponding map properties

(possibly including the actual map element itself), or their full or partial absence; 9. spatial-data-change action resolution -determining the local scope of spatial-data-change (add, delete, change, or combination thereof).

The evaluation is organized as a decision tree or decision graph, whereby evaluation steps are sequentially executed. For each step, decisions are structured such that:

- (at least) two outcomes are possible; and

- (at least) one outcome translates into a trivial action. Each decision is addressing: the fact whether or not the event and the associated meta data agrees with the local map context (for instance related to spatial relevance, to successful location referencing, or to event property matching such as a road closure corresponding accurately to the targeted map element which so far was open for traffic); any explicit disagreements between present local map and the local map "anticipated" by the spatial-data-change message would make this a non-trivial outcome (for instance, the spatial-data-change message's event is missing in the local map despite the spatial- data-change message's time stamp being older than the local map's currency); the (lack of) co-existence of multiple related spatial-data-change messages in time and space; the decision outcome will tell whether or not spatial-data-changes are incomplete, overlapping, inconsistent, contradicting, or otherwise non-trivial; A real-world change that is received or retrieved as an instance of a spatial-data- change message more than once from different sources may fall into either of the above cases. In the former case, the first spatial-data-change message results in a trivial outcome, while a later spatial-data-change message coinciding in scope would no longer require the same change which also is a trivial outcome (two decision instances in total). In the latter case, multiple spatial-data-change messages overlapping/coinciding in scope are handled by a single evaluation step and -depending on coherence on the overlapping part- resulting in a trivial outcome (one overall decision instance).

Trivial outcomes are directly executable, and actions can include: continued with next evaluation step, executed map updating action corresponding to event, event not applicable, event reevaluated when causal condition is met, event is obsolete.

As immediate consequence, this means the second or application system 200 could choose to limit update processing to certain "safe" classes of spatial-data-change messages and to impose operational constraints in order to offer high confidence and low risk, without requiring hugely sophisticated decision logic. Such "safe" classes of spatial-data-change messages target spatial-data-changes that are not complex in nature, and as such would not cover topology changes, next-character name indices, or the like. As an example, for a geo-coding & address visualization application, a "safe" spatial-data-change message can include changes in road accessibility (such as a road closure, a changed one-way, a vehicle access restriction, and a cancellation/expiration thereof), or a change in coverage and granularity of the 2-D or 3-D city model. There are no generally applicable objective criteria for non-complex spatial-data- change messages; however, for a given second or application system 200 it can be determined what can be declared "safe", depending on the application functionality, system architecture, map data organization and storage, system performance, communication channel characteristics, and the like.

Systems that are optimized towards intake of updates may support a reasonably large number of classes of "safe" spatial-data-change messages, even including map properties that are core to the application functionality (such as routing attributes in a in- vehicle navigation application, provided that a dynamically weighted routing algorithm is used).

Operational constraints may be to utilize a single source of spatial-data-change messages (or multiple complementary sources); to utilize a source(s) recommended by the vendor of the second system and possibly published by the same vendor; to rely on availability of proprietary IDs of the map element which is subject to a change; to enforce periodical full replacement of the local map with an updated version; or the like.

With respect to non-trivial outcomes, the decision tree or decision graph shall offer step-by-step break-down of complexity in order to separate trivial constellations from non-trivial ones and to ultimately translate non-trivial actions into trivial actions (which can be directly executed). Nodes in the decision tree or graph can include: ranking - determine if there are competing spatial-data-change messages (partially or fully addressing the same map element and/or property), and if so apply relative ranking for selecting most credible spatial-data-change message by using meta data elements, possibly in combination with user preferences (user-defined ranking of spatial-data-change message sources), or by requesting for user-selection; common denominator — determine if there are competing spatial-data-change messages (partially or fully addressing the same map element and/or property), and if so extract minimum event properties common to all spatial-data-change messages; superset — determine if there are competing spatial-data-change messages (partially or fully addressing the same map element and/or property) whose overlapping general scope is non-conflicting, and if so assemble the sum of the event properties of all spatial-data-change messages; partial change - in case of partial correspondence of the spatial-data-change message's general scope and its local scope, determine whether both scopes are without contradicting aspects (i.e., the spatial-data-change message's event is a mix of as-if- already-changed and not -yet-changed aspects), and if so identify not-yet-changed aspects; best fit - determine if a systematic manipulation of a spatial-data-change message's event property (for at least one of it's aspects) resolves a conflict in scope, and if so accept manipulated aspect for further processing (as an example, upgrade or downgrade road classification or road categorization in order to fit spatial-data-change message into local map); clustering - determine a group of spatial-data-change messages based on spatial and/or network extent criteria, possibly specialized based on (a set of) spatial-data- change's event property/ies, which if not resolvable can be generalized into a "super spatial-data-change message" for the cluster as a whole and simplified to a general alert towards the navigation application ("map element currently subject to spatial-data- change", "map property/ies currently subject to spatial-data-change", or the like); credibility - determine credibility of spatial-data-change message by using meta data elements, and if above threshold accept spatial-data-change's event properties as new data state, overwriting the old data state regardless of local scope (as an example, a spatial-data-change message wants to reverse the one-way direction, however the local map does not have a one-way restriction for the street in questions).

If there are competing spatial-data-change messages (partially or fully addressing the same map element and/or property), a decision has to be made which spatial-data- change message prevails to determine which changes in reality should be applied to the digital map database. It could happen that two spatial-data-change messages address the same event but with different description (e.g. different street names). In this case, the process decides which of the corresponding descriptions is regarded to be the most appropriate. The determination can be based on at least one of the following characteristics: ranking, common denominator, superset, partial change, best fit, clustering, credibility. However, it could also happen that competing spatial-data- change messages address the same event with different event properties. In that case, the update applied to the digital map is a combination of event properties of the relevant events in dependence of the associated relevance's and a new event description will be obtained. Which of the event properties should be taken can be based on at least one of the following characteristics: ranking, common denominator, superset, partial change, best fit, clustering, credibility. In this way a customized spatial-data- change message is generated, which comprises content that has been obtained from different spatial-data-change messages.

Upon execution of any customized spatial-data-change messages that are subject to partial and/or manipulated interpretation as per above and optionally for normal spatial-data-change messages, a record of customization will be created alongside the original spatial-data-change message instance in order to serve roll-back to an older data state, such as cancellation of transactional data processing in general and execution of spatial-data-change expiration/cancellation actions in particular. The record of customization describes all changes made in the map database caused by a spatial-data- change message enabling to roll-back the spatial-data-changes. The record of customization could also be used to roll-back a spatial-data-change message in the case the consistency check 414 fails.

Additionally, the balance of a customized spatial-data-change message compared to the original spatial-data-change message may be recorded for generating a new, "virtual" spatial-data-change message which may play a role in potential later evaluations in the context of new spatial-data-change messages acquired and/or old spatial-data-change messages disappearing (such as being retired or expired).

If a spatial-data-change message has been identified as relevant, the spatial-data- change will be applied to the digital map 204 in step 412. The act of applying the spatial-data-change may comprise any appropriate technique of making the change information accessible to the map application, including appending the application map database, overriding or deleting data structures in the application map database, creating and maintaining an overlay layer, etc..

In view of the above, if the system 200 acquires a multitude of spatial-data- change messages to be applied to the digital map database, in an embodiment the update-application will evaluate each spatial-data-change message by taking into account the other spatial-data-change messages. If the spatial-data-change is applicable, the map-elements and/or map properties of the digital map corresponding to the event could be marked as to be updated and the corresponding update actions could be stored in a memory. The mark to be updated, could be used to determine whether an equivalent spatial-data-change is received, to determine whether the other spatial-data- change is consistent with the corresponding update and if inconsistent to determine which of the two conflicting spatial-data-change messages is the most appropriate. After all spatial-data-change messages have been processed, the marked map-elements and map -properties will be update according to the associated update actions stored in said memory. The above embodiment makes clear that the meta data is very suitable to provide a good and efficient algorithm to select and apply the most relevant spatial- data-change messages from a multitude of acquired spatial-data-change messages. In this way, the possibility of an inconsistent or inaccurate map-database can be reduced. For example, if two spatial-data-change messages address the change of a street name, but with different spelling, the spatial-data-change message published by a preferred publisher is selected. If the spatial-data-change messages regarding a similar event were processed one -by-one, the street name of last processed spatial-data-change message would be the result.

It could happen that a spatial-data-change message is regarded relevant for the application map database, but could still not be applied. This could happen if the spatial-data-change message depends on a spatial-data-change message which is currently not received or has to be applied at a particular moment in time. Another example is that the meta-data indicates that the spatial-data-change message should only be applied to particular version of a map vendor. If the map application comprises an older map version, the map application could store the spatial-data-change message in a memory for later use, i.e. after the application map database is updated to the particular map version. Another example might be that a spatial-data-change simply comes from a different vendor (i.e. public service government source that offers data on new turn restrictions) and wherein a corresponding street is still not in the application map. For those cases, the method comprises, not shown, storing the spatial- data-change message for further processing within the map application if remaining relevant.

In an embodiment of the invention, the action storing the spatial-data-change message for further processing within the map application if remaining relevant is performed whether the spatial-data-change is applied to the application map database or not. This embodiment is suitable for new map -replacements. The invention enables map applications to update their application map-database from different sources. It could happen that a replacement map from the map vendor of the map application is less up-to-date than the content of the current application map DB and thus does not reflect all applied spatial-data-change messages. By storing all relevant spatial-data- change messages, the map application could verify after applying a map-replacement which of the stored spatial-data-change messages are incorporated in the map- replacement. Those that are incorporated in the map-replacement could be discarded from the storage because they are not longer needed. Those that are not reflected in the map-replacement can now be reapplied to the application map DB, to update the replaced part of the application map database. In this embodiment, the phrase "if remaining relevant" should be interpreted as spatial-data-change not yet reflected in latest applied vendors map database and therefore possibly relevant to update a later version of the vendors map database.

In an embodiment of the invention, the method comprises, not shown, replacing at least a part of the application with a replacement version, and reevaluating the relevance of the stored spatial-data-change messages. Reevaluation of a stored spatial- data-change message is necessary as it could be that it is not reflected in the replacement version or it could comprise a spatial-data-change which is only relevant in a particular time -period. In the cases that it is represented in the replacement database or the time period is no longer relevant, the method comprises discarding a stored data-change-message, as it is no longer needed or applicable.

Optionally, a final step 414, related to actual update actions in response to resolved spatial-data-changes, the system 200 may carry out consistency checks at the end and/or through-out the update actions. Such checks may verify discontinuities between connected map elements or discontinuous properties thereof, the occurrence of contradicting map properties, or the like. Found inconsistencies lead to a roll-back or (part of) the update actions, possibly followed by a renewed evaluation process (such as modified customization).

Figure 4 suggests that the individual steps have to be executed in a subsequent predefined order. It should be noted that the invention is not limited to this order. For example, individual sub-steps from 408 defined by the nodes of the decision tree or decision graph, may be performed prior to step 406, such as prioritization or temporal relevance check. Furthermore, if sub-step 410, decoding DLR to find match, is the first action to determine the relevance, the step can be regarded as a step preceding the evaluation step 408. Furthermore, it might be possible that firstly the meta data is evaluated and then the event data. In that case, a part of step 404, i.e. retrieve event data and step 406, retrieve DLR from event, will be sub-steps included in step 408. Therefore, other embodiments of the method of processing a spatial-data-change message are obvious to the skilled person without departing from the scope of the invention.

It should be noted that the spatial-data-change messages could be used to generate a new spatial-data-change message or a combined spatial-data-change message. In that case, the one or more spatial-data-change messages from one or more sources over a defined period are processed to determine the appropriate changes in the digital map to be applied, and said changes are used to generate a new spatial-data- change message or a new sequence of smaller spatial-data-change messages. In this embodiment of the invention, the method of processing a spatial-data-change message corresponds to action acquiring an indication of a spatial-data-change of the method of generating a map-agnostic spatial-data-change message. This embodiment enables a spatial-data-change message supplier to verify/compare the changes from different source and to generate a new spatial-data-change message with consistent and reliable data. By adding his identity to the meta data in the spatial-data-change message, a receiving system applying the method according to the invention could detect easily that the changes in the spatial-data-change message are reliable and should preferably implemented in the digital map of the receiving system.

In an embodiment of the invention, the method further comprises the action of registering the number of spatial-data-change messages applied, and not applied to enable an application to generate a report to the providers of spatial-data-change messages. They could use this report to improve their service. For each data-source, i.e. provider of spatial-data-change messages, a record could be present which identifies the number of spatial-data-change messages applied, and not applied. The information stored in the record could also be used to differentiate between fully applied, partially applied and even identify which content of a spatial-data-change message is applied. The information could further indicate why a spatial-data-change message is not applied. Some examples are: no match for DLR found, out-dated, reliability level to low, etc. The registered information could further be used in the map application to adapt internal parameters to determine the priority of spatial-map-change messages. For example, a spatial-map-change message coming from a source which could frequently not be applied will obtain a lower priority level than a spatial-map-change message coming from another source which could more frequently applied to the application map database.

Figure 7 shows a simplified example of a decision graph applied on a map- change message. The spatial-data-change message describes a change in reality related to the blockage of major expressway due to accident; road is closed in both directions for several days. The spatial-data-change message application is running on a PND (Portable Navigation Device) with a locally stored street-level navigable map database.

In the decision graph tl, t2 indicate that the result of the decision is a trivial outcome and ntl, nt2, nt3 indicate non-trivial outcomes.

Step 1 : prioritization

(tl) more important event(s) to be processed first -> re-evaluate step 1 later (t2) no other events of higher priority -> step 2

Step 2: location referencing decoding (tl) matching location is found -> step 3 (t2) matching location not found -> discard spatial-data-change

Step 3: spatial relevance (tl) location is outside "area of operation" -> discard spatial-data-change (tl) location is within "area of operation" -> step 4

Step 4: temporal relevance (tl) event is younger than local map -> step 5

(tl) event is older than local map -> discard spatial-data-change (very unlikely in this particular example)

Step 5: event property matching (tl) local location of event is not blocked -> step 7 (normal acceptance threshold) (nt2) local location of event is attributed as not passable (triggered by another spatial- data-change) -> step 6

(nt3) local location of event is attributed as not passable (not triggered by another spatial-data-change message) -> step 7 (high acceptance threshold) Step 6: resolution of competing spatial-data-change messages

(tl) state of reality in local map correspond with new state of reality after the spatial- data-change message -> spatial-data-change message is obsolete (nt2) state of reality in local map does not (fully) correspond with new state of reality after the spatial-data-change message -> further non-trivial decision steps (step 8) Step 7: credibility check

(tl) spatial-data-change message source meets acceptance threshold -> initiate map updating action

(t2) spatial-data-change message source does not meet acceptance threshold -> discard Step 8: not elaborated here

In figure 5, an overview is given of a computer arrangement 500 suitable for implementing the present invention. The computer arrangement 500 comprises a processor 511 for carrying out arithmetic operations. The processor 511 is connected to a plurality of memory components, including a hard disk 512, Read Only Memory (ROM) 513, Electrical Erasable Programmable Read Only Memory (EEPROM) 514, and Random Access Memory (RAM) 515. The memory components comprises a computer program comprising data, i.e. instructions arranged to allow the processor 511 to perform the method for generating a spatial-data-change message or the method for processing a spatial-data-change message according to the invention. Not all of these memory types need necessarily be provided. Moreover, these memory components need not be located physically close to the processor 511 but may be located remote from the processor 511. The digital map database associated with the methods may or may not be stored as part of the computer arrangement 500. For example, the digital map database may be accessed via web services. It might even be possible, that the generation of a DLR is performed by a process running on another processor. The processor 511 is also connected to means for inputting instructions, data etc. by a user, like a keyboard 516, and a mouse 517. Other input means, such as a touch screen, a track ball and/or a voice converter, known to persons skilled in the art may be provided too. A reading unit 519 connected to the processor 511 may be provided. The reading unit 519 is arranged to read data from and possibly write data on a removable data carrier or removable storage medium, like a floppy disk 520 or a CDROM 521. Other removable data carriers may be tapes, DVD, CD-R, DVD-R, memory sticks, solid state memory (SD cards, USB sticks) compact flash cards, HD DVD, blue ray, etc. as is known to persons skilled in the art.

The processor 511 may be connected to a printer 523 for printing output data on paper, as well as to a display 518, for instance, a monitor or LCD (liquid Crystal Display) screen, head up display (projected to front window), or any other type of display known to persons skilled in the art. The processor 511 may be connected to a loudspeaker 529 and/or to an optical reader 531, such as a digital camera/web cam or a scanner, arranged for scanning graphical and other documents.

Furthermore, the processor 511 may be connected to a communication network 527, for instance, the Public Switched Telephone Network (PSTN), a Local Area Network (LAN), a Wide Area Network (WAN), Wireless LAN (WLAN), GPRS, UMTS, the Internet etc. by means of I/O means 525. The processor 511 may be arranged to communicate with other communication arrangements through the network 527.

The data carrier 520, 521 may comprise a computer program product in the form of data and instructions arranged to provide the processor with the capacity to perform a method in accordance to the invention. However, such computer program product may, alternatively, be downloaded via the telecommunication network 527 into a memory component.

The processor 511 may be implemented as a stand alone system, or as a plurality of parallel operating processors each arranged to carry out sub tasks of a larger computer program, or as one or more main processors with several sub-processors. Parts of the functionality of the invention may even be carried out by remote processors communicating with processor 511 through the telecommunication network 527.

The components contained in the computer system of Figure 5 are those typically found in general purpose computer systems, and are intended to represent a broad category of such computer components that are well known in the art.

Thus, the computer system of Figure 5 can be a portable device, such as a PDA, navigation device, a personal computer, a workstation, a minicomputer, a mainframe computer, etc. The computer can also include different bus configurations, networked platforms, multi-processor platforms, etc. Various operating systems can be used including UNIX, Solaris, Linux, Windows, Macintosh OS, and other suitable operating systems.

The method of processing a spatial-data-change message according to the invention is also very suitable to be implemented in navigation systems comprising a digital map database. Such navigation systems may be build for a vehicle, (e.g. car, van, truck, motorbike) or mobile device (personal digital assistant (PDA), mobile phone, handheld computer, or a personal navigation device). In that case, the navigation system comprises a computer implemented system with parts as shown in figure 5. A computer readable memory carries a digital map. The computer implemented system comprises further an input device for retrieving the spatial-data- change messages. The spatial-data-change messages could be retrieved from a removable storage medium or other removable data carrier. In that case, the system comprises a reading unit 519 for reading the application digital map from the memory device. The spatial-data-change messages could also be retrieved via a communication network 527 by means of I/O means 525 from a transmission medium. The spatial- data-change messages could also be retrieved via an optical reader 531.

The foregoing detailed description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The described embodiments were chosen in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.

Claims

1. Method of generating a map-agnostic spatial-data-change message, the method comprising:

- acquiring an indication of a spatial-data-change;

- selecting one or more map elements from a master digital map to be associated with the spatial-data-change to specify the location of the spatial-data-change;

- generating an event comprising for each of said one or more map elements a dynamic location reference and a description corresponding to the spatial-data-change;

- generating meta data associated with the event;

- combining the event and the meta data to obtain the map-agnostic spatial-data-change message.

2. Method according to claim 1, wherein the map-agnostic spatial-data-change message is a version-agnostic spatial-data-change message.

3. Method according to claim 1 or 2, wherein the dynamic location reference is generated from content of the master digital map prior to the spatial-data-change.

4. Method according to any of the claims 1 - 3, wherein the event comprises a description of the properties of the state of the master digital map prior to the spatial- data-change and a description of the state of the master digital map after the spatial- data-change.

5. Method according to any of claims 1 - 4, wherein the spatial-data-change message comprises an attribute identifying the nature of the spatial-data-change, wherein the nature could be one selected from a group of categories comprising: independent (new) map element or property, changed map element or property, deleted map element or property, map element or property flagged for (unspecified) changes (for instance for addressing large scale reconstruction work in progress, traffic flow redirected or closed during seasonal events, or the like).

6. Method according to any of the claims 1 - 5, wherein the event comprises at least one map element and one or more map properties providing the description corresponding to the spatial-data-change, wherein a map element could be an entity of the master digital map selected from the group comprising: road element, linear section, intersection, point object, explicit area object, implicit area object (in terms of the contained map elements), and a map property describes an attribute of or relationship with the map element.

7. Method according to any of the claims 1 - 6, wherein the method further comprises:

- acquiring a spatial-data-change indication having a determined relationship with a previous spatial-data-change message;

- generating additional meta data associated with the spatial-data-change indication, the meta data comprising a reference to the map-agnostic spatial-data-change message and an attribute indicating one or more intentions selected from a group comprising: cancellation, expiration, continuation, unknown status, uncertain status, change in estimated duration, change in credibility, change in provided level of detail;

- obtaining a subsequent spatial-data-change message comprising at least the additional meta data.

8. Method according to any of the claims 1 - 7, wherein the map-agnostic spatial- data-change message is rendered as a graphical barcode or semacode structure.

9. Method of processing one or more map-agnostic spatial-data-change messages to change the content of an application digital map, the one or more map-agnostic spatial- data-change messages comprising an event describing a spatial-data-change and meta data, the method comprising:

- acquiring the map-agnostic spatial-data-change message; - retrieving the event and associated meta data from the map-agnostic spatial-data- change message;

- retrieving a dynamic location reference from the event; - evaluating the relevance of the event for the application digital map comprising the action decoding the dynamic location reference to find a match in the application digital map; and

- if relevant, applying at least partially the spatial-data-change to the application digital map in dependence of the relevance of the event.

10. Method according to claim 9, wherein the map-agnostic spatial-data-change message is a version-agnostic spatial-data-change-message.

11. Method according to claim 9 or 10, wherein the relevance of the event is derived from at least one of: the attributes describing the spatial-data-change and the meta data.

12. Method according to any of the claims 9 - 11, wherein the relevance is derived by using a decision graph of logical evaluations, wherein for each decision at least two possible outcomes are possible of which at least one outcome triggers a trivial action, wherein a trivial action is an action that is directly executable and is selected from a group comprising at least two of: continued with next evaluation step, executed map updating action corresponding to event, event not applicable, event reevaluated when causal condition is met, event is obsolete.

13. Method according to any of the claims 9 - 12, wherein evaluating comprises:

- determining a group of co-existing events;

- determining one or more relevant events from said group based on at least one of the following characteristics: ranking, common denominator, superset, partial change, best fit, clustering, credibility.

14. Method according to claim 13, wherein applying comprises

- combining relevant events in dependence of the associated relevance's to obtain a new event description to be applied to the application digital map.

15. Method according to any of the claims 9 - 14, wherein the method further comprises generating a record enabling to undo the applied spatial-data-change in the application digital map.

16. Method according to any on of the claims 9 - 15, wherein the method further comprises: carrying out a consistency check on discontinuities between connected map elements or discontinuous properties thereof, occurrence of contradicting map properties and the like.

17. Method according to claim 16, wherein the method further comprises undoing the event causing an inconsistency in the application digital map.

18. Method according to any of the claims 9 - 17, wherein the map-agnostic spatial- data-change message is acquired from a graphical barcode or semacode structure.

19. A computer implemented system for generating a map-agnostic spatial-data- change message associated with a master digital map, the system comprising a processor (511) and memory (512; 513; 514; 515) connected to the processor, the memory comprising a computer program comprising data and instructions arranged to allow said processor (511) to perform any of the methods according to claims 1 - 8.

20. A computer implemented system as claimed in claim 17, arranged to render the map-agnostic spatial-data-change message as a graphical barcode or semacode structure.

21. A computer implemented system for processing a map-agnostic spatial-data- change message comprising an event describing a spatial-data-change and meta data, the system comprising a processor (511) and memory (512; 513; 514; 515) connected to the processor, the memory comprising a computer program comprising data and instructions arranged to allow said processor (511) to perform any of the methods according to claims 9 - 18.

22. Map-agnostic spatial-data-change message comprising an event and meta data, wherein the event comprising a dynamic location reference for each of one or more map elements associated with a spatial-data-change to indicate the location of said spatial-data-change and a description corresponding to said spatial-data-change and wherein the meta data enables a digital map application comprising an application digital map using at least the meta data to evaluate the relevance of the event for its application digital map.

23. Map-agnostic spatial-data-change message according to claim 22, wherein the map-agnostic spatial-data-change message is a version-agnostic spatial-data-change message.

24. Map-agnostic spatial-data-change message according to claim 22 or 23, wherein the map -agnostic spatial-data-change message is rendered as a graphical barcode or semacode structure.

25. A computer program product comprising data and instructions that can be loaded by a computer arrangement, allowing said computer arrangement to perform any of the methods according to claims 1 - 18.

26. A processor readable medium provided with a computer program product comprising data and instructions that can be loaded by a computer arrangement, allowing said computer arrangement to perform any of the methods according to claims 1-18. H= H= H= H= H= H= H=