JP5526831B2 - Drawing data management device - Google Patents

Description

  The present invention relates to a drawing data management apparatus.

  2. Description of the Related Art Conventionally, a rectangular mesh obtained by dividing a management area into a plurality of parts has been used as a data management unit when computer-drawing map drawing data indicating a certain area (hereinafter referred to as a management area).

  Here, when the mesh is used, as position data used in the drawing data of each mesh, a relative coordinate system only for the mesh, that is, a value of a coordinate system with the representative point of the mesh as an origin is used. Will be used. Therefore, when processing graphic data elements (road lines, facility lines, etc.) spanning multiple meshes, the position data of the graphic data elements is used as the relative coordinate system position data (hereinafter referred to as relative position data) in the selected mesh. Must be converted into position data (hereinafter referred to as absolute position data) in the absolute coordinate system of the management area of the division source.

  For example, Patent Literature 1 discloses a technique that uses a lower left corner point of a mesh or an intersection of diagonal lines of a mesh as a representative point of a selected mesh. And in patent document 1, the representative point absolute position data which shows the position in the management area | region of the representative point of this selection mesh is shown in the size data of a mesh, the mesh number of a selection mesh, and the position in the self mesh of the representative point of a selection mesh. There is also disclosed a technique for converting relative position data to absolute position data by obtaining by calculation processing based on representative point relative position data. Further, it is disclosed that the points other than the representative point in the selected mesh are obtained based on the relative position (that is, offset) from the representative point of the selected mesh.

  Patent Document 2 discloses a technique that uses a set of shape points made up of latitude and longitude coordinates when expressing a curved geographic feature such as a road (that is, a graphic data element).

JP-A-11-212449 JP-A-11-265441

  However, the technique disclosed in Patent Document 1 has a problem that the data size to be handled becomes enormous and management of drawing data becomes difficult. This problem will be described in detail below.

  First, it is known that a mesh in drawing data indicating a map is generally 32768 × 32768 pixels. Here, since the above-mentioned offset is expressed within the frame of this mesh, 16 bits (that is, 2 bytes) are used for the X coordinate and 2 bytes are used for the Y coordinate to express one shape point in the mesh. In other words, when storing shape point data, a storage area of at least 4 bytes must be secured for one shape point.

  As disclosed in Patent Document 2, when a curved graphic data element such as a road is expressed, a plurality of shape points are used. Therefore, in the technique disclosed in Patent Document 1, when a curved graphic data element such as a road is expressed, the data size to be handled becomes enormous. For example, if the data size to be handled becomes enormous, the processing load using the drawing data increases and the processing takes time. Further, when the data size to be handled becomes enormous, the communication load when exchanging drawing data by communication increases, and it takes time to update drawing data by communication. Accordingly, when the data size to be handled becomes enormous, it becomes difficult to manage drawing data.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a drawing data management apparatus that can reduce the size of data to be handled and facilitate the management of drawing data. There is to do.

According to the drawing data management device of claims 1 and 2, the representative point represented by the relative coordinates expressed by the predetermined number of bits with the reference point set at a predetermined position on the mesh as the base point is further set as the base point. The relative coordinates of the point sequence representing the graphic element on the mesh are expressed by a compression bit number smaller than the predetermined bit number. Therefore, a point sequence representing a graphic element can be expressed with a smaller number of bits than the predetermined number of bits. Therefore, a point sequence representing a graphic element is represented by the predetermined number of bits as compared with a configuration in which a point sequence representing a graphic element using the reference point as a base point is represented by the predetermined number of bits in the same manner as the representative point is represented by a relative coordinate. The data size to be handled can be further reduced by the amount that can be expressed by the number of compressed bits smaller than the number of bits.

In addition, according to the above configuration, the data size to be handled can be further reduced. Therefore, the processing time using the drawing data can be further reduced, the processing time can be reduced, and the drawing data can be exchanged by communication. In this case, it is possible to further reduce the time required for updating the drawing data through communication by further reducing the communication load. As a result, according to the above configuration, the management of drawing data can be made easier.
Furthermore, according to the configuration of the first aspect, the relative coordinates of each point sequence of the graphic element can be expressed only by numerical values of 0 or more, and the data size to be handled can be further reduced.
According to the second aspect of the present invention, the data size of the electronic map drawing data handled by the vehicle-mounted navigation device can be reduced, and the electronic map drawing data can be managed more easily.
In addition, according to the configuration of claim 2, since the representative points are added, each point of the graphic element that cannot represent all of the point sequences of the graphic elements with only one representative point is represented by the number of compression bits. All of the columns can be expressed by the number of compressed bits. Therefore, according to the above configuration, it is not necessary to cause a situation in which a point sequence that cannot be expressed by the number of compressed bits must be expressed by a predetermined number of bits, and the data size to be handled can be more reliably reduced, and drawing data can be managed. Can be made easier.
Further, according to the configuration of claim 2, since a plurality of representative points are set for a graphic element that cannot represent all of the point sequences of the graphic elements with only one representative point by the number of compression bits, only one representative point is set. With respect to a graphic element that can express all of the point sequences of graphic elements with the number of compressed bits, a plurality of representative points are not set. Therefore, according to the above configuration, an increase in data size due to the addition of unnecessary representative points can be suppressed.

According to a third aspect of the present invention, the drawing data is electronic map drawing data related to the drawing display contents of an area on the map divided into a plurality of meshes, and the graphic elements are the topography, roads, and It is good also as an aspect which is at least one of facilities. According to this, by applying the present invention to an in-vehicle navigation device or the like, the data size of the electronic map drawing data handled by the in-vehicle navigation device or the like can be reduced, and the management of the electronic map drawing data is made easier. It becomes possible to do.

Further, as in claim 4 , the dot sequence of the graphic elements may be expressed in numerical values of 0 or less by the number of compression bits. According to this, it is possible to set a representative point without being limited to a position where the relative coordinates of each point sequence of the graphic element can be expressed by a numerical value of 0 or more. Therefore, the degree of freedom of the position for setting the representative point can be increased, and the setting of the representative point can be facilitated.

In this case, as shown in claim 5 , the representative point may be set based on a point corresponding to the center of each point sequence of the graphic element, or as in claim 6 . Alternatively, a representative point may be set at a point corresponding to the center of each point sequence of the graphic element.

Further, as in claim 7 , the region belongs to the first quadrant of the coordinate plane, and the reference point may be set to the lower left corner point of the mesh. According to this, the lower left corner point of the mesh is the point closest to the origin of the coordinate plane.

  In the aspect in which the reference point is set at the lower left corner point of the mesh, as shown in claim 7, the point sequence of the graphic element is expressed only by a numerical value of 0 or more depending on the number of compression bits. However, it is good also as an aspect set to the point nearest to the reference point among the four corner points of the circumscribed rectangle of the graphic element. In this aspect, the relative coordinates of each point sequence of the graphic element can be expressed only by a numerical value of 0 or more, and the data size to be handled can be further reduced.

Further, as described in claim 9, a plurality of representative points may be set for at least one graphic element on the mesh.

Further, as in the tenth aspect, with respect to a graphic element that cannot represent all of the respective point sequences of the graphic element with only one representative point by the number of compression bits, a plurality of representative points may be set. According to this, since representative points have been added, even for graphic elements that cannot represent all of the point sequences of the graphic elements with a single representative point, all of the point sequences can be expressed with the number of compressed bits. It is possible to express. Therefore, according to the above configuration, it is not necessary to cause a situation in which a point sequence that cannot be expressed by the number of compressed bits must be expressed by a predetermined number of bits, and the data size to be handled can be more reliably reduced, and drawing data can be managed. Can be made easier.

  In addition, since a plurality of representative points are set for a graphic element in which not all the point sequences of the graphic element can be represented by the number of compression bits with only one representative point, all of the point sequences of the graphic element can be formed with only one representative point. A plurality of representative points are not set for graphic elements that can be expressed by the number of compression bits. Therefore, according to the above configuration, an increase in data size due to the addition of unnecessary representative points can be suppressed.

In this case, as in claim 1 1, for the one graphic element that can not be represented by the number of compressed bits all sequence of points only in the graphic element representative points, the graphic elements are divided, It is good also as an aspect by which the representative point is set for every divided part.

Further, according to the configuration of claim 1 2, for all the graphic elements on the mesh, all of the sequence of points representing the figure elements, expressed by the number of compressed bits as a base point a representative point that is set to each graphic element Therefore, it is possible to further reduce the data size to be handled and further facilitate the management of the drawing data.

Furthermore, as according to claim 1 3, the number of compressed bits may be embodiments in which single bits smaller than the predetermined number of bits.

Furthermore, as according to claim 1 4, the number of predetermined bits is two bytes, the number of compressed bits may be mode in which the 1-byte.

1 is a block diagram showing a schematic configuration of a map data update system 100. FIG. 1 is a block diagram showing a schematic configuration of a navigation device 1. FIG. It is a schematic diagram for demonstrating the remodeling structure of map data. It is a schematic diagram which shows the shape point sequence of the road A on a mesh, a reference point, and a representative point. It is a schematic diagram for demonstrating an example of the representative point set on a mesh. It is a schematic diagram for demonstrating an example of the representative point set on a mesh.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a map data update system 100 to which the present invention is applied. A map data update system 100 shown in FIG. 1 includes a navigation device 1 and a map center 2 mounted on a vehicle.

  The map center 2 includes a server, a communication device capable of communicating with the navigation device 1 via a network such as the Internet (that is, a communication network), a storage device as a database that holds map data, and A control device for controlling communication is provided.

  The map center 2 may be composed of one server or may be composed of a plurality of servers. The storage device of the map center 2 holds the latest map data when there is a change in map data due to a change in roads or facilities or a new road or facility. Details of the map data will be described later.

  The navigation device 1 is mounted on a vehicle such as an automobile and has a function of performing route guidance similar to that of a general navigation device, and communicates with the map center 2 via a network. It has a function.

  Here, a schematic configuration of the navigation device 1 will be described with reference to FIG. FIG. 2 is a block diagram illustrating a schematic configuration of the navigation device 1. As shown in FIG. 2, the navigation device 1 includes a position detector 11, a map data input device 16, a storage medium 17, an operation switch group 18, a remote control 19, a remote control sensor 20, a center communication unit 21, an external memory 22, and a display device 23. , A voice recognition unit 24, a voice output device 25, and a control device 26 connected thereto.

  The position detector 11 has a known geomagnetic sensor 12, a gyroscope 13, a distance sensor 14, and a GPS receiver 15 for GPS (Global Positioning System) that detects the current position of the vehicle based on radio waves from a satellite. doing. These sensors 12 to 15 have errors of different properties, and are configured to be used while being complemented by a plurality of sensors. Depending on the accuracy, a part of the above may be used, and a steering rotation sensor, a vehicle sensor for each rolling wheel, or the like may be used.

  The map data input device 16 is a device for inputting various data including map data and mesh management information stored in the storage medium 17. Details of the map data and mesh management information will be described later.

  Here, the configuration of the map data will be described. The map data is stored in the storage medium 17 for each divided range called a rectangular mesh (map section) by dividing a target area (hereinafter, management area) into a mesh shape. The map data that is divided and stored in units of meshes in this way is mainly the road data for displaying roads according to actual roads and the background when displaying maps such as natural terrain and facilities. It consists of background data and character data for displaying a place name, facility name, road name, etc. on a map. If the map data of the whole Japan is handled, the management area is a range including the whole of Japan. One mesh is assumed to be 32768 × 32768 pixels. The following description will be continued assuming that the management area belongs to the first quadrant (x> 0, y> 0) of the coordinate plane.

  The road data includes link data indicating a road and node data. A link (road link) refers to the distance between nodes when the roads on a map are divided into multiple nodes such as points that intersect, branch, and merge, points that have ancillary facilities, and points that are set as guide points. The road is constructed by connecting the links. However, when the road shape is other than a straight line, a shape interpolation point is set between the nodes in order to simulate the actual road shape. In this case, the line segment connecting the node and the shape interpolation point or connecting the shape interpolation points is called a segment, and the link is composed of a plurality of segments.

  The link data includes a unique number (link ID) identifying the link, a link length indicating the link length, link shape information, road link start and end node coordinates, road name, road type, road width, number of lanes, It consists of data such as the presence / absence of a right / left turn lane, the number of lanes, speed limit, etc. The link coordinate data describes the coordinates of the start and end of this link. Note that the link data includes data on a plurality of links indicating road portions that are included in one mesh and have the same name and traveling conditions of the vehicle. For example, it is assumed that road A and road B are included in one mesh. In this case, the road data of the mesh has link data corresponding to the road A and link data corresponding to the road B. The link shape information is composed of a coordinate sequence indicating the coordinate positions of both ends of the link and a shape interpolation point representing the shape between them.

  On the other hand, the node data is data such as a node ID given a unique number for each node on the map, node coordinates, node name, a connection link ID describing a link ID of a link connected to the node, and an intersection type. Consists of

  In addition to displaying a map, the road data is used to give the shape of a road when performing map matching processing, or used to search for a guide route to a destination.

  The background data is data in which each facility or terrain on the map is associated with coordinates on the map corresponding to the facility (for example, corresponding to a line indicating each facility or terrain). In addition, regarding the facility, the types, names, and address data of various facilities are included. The facilities mentioned here indicate buildings such as houses, buildings, stations, airports, stadiums, and bridges. The character data is data for displaying a place name, a facility name, a road name, and the like on a map, and is associated with coordinate data corresponding to the position to be displayed. The road data, background data, and character data correspond to the drawing data in the claims.

  Moreover, the name of the mesh is named for convenience in the present embodiment. Therefore, it is not necessarily limited to these names. For example, the mesh may be referred to as a parcel or a management unit.

  Note that the map data may have a hierarchical structure that is divided into a plurality of levels based on, for example, the size of the range to be covered. In the following, as an example, the map data is assumed to have a hierarchical structure divided into three levels (level 0 to level 2 in FIG. 3) from the wide area side to the detailed side as shown in FIG. Continue the explanation. As shown in FIG. 3, the relationship between the data in each layer corresponds to one mesh of data on the wide area side that covers a wider area and four meshes of data on the detailed side that covers a smaller area. It is layered as follows.

  In addition, here, a configuration is shown in which hierarchization is performed so that four meshes of detailed data correspond to one mesh of data on the wide area side, but the present invention is not necessarily limited thereto. For example, a configuration may be adopted in which a single mesh of data on the wide area side is hierarchized so that a plurality of meshes other than four pieces of data on the detailed side exist.

  Furthermore, here, a configuration in which the hierarchical structure is divided into a plurality of layers based on the range of the range to be covered is shown. However, the present invention is not limited to this, and the structure is divided into a plurality of layers based on other criteria. The structure may be a divided hierarchical structure. For example, a configuration having a hierarchical structure divided into a plurality of levels based on the information amount of the road network may be used.

  The map data can be updated with a mesh as a unit, and is managed in units of mesh. That is, the map data can be partially updated on a mesh basis. Moreover, mesh ID as an identifier for identifying each mesh is added to map data for every mesh. Note that the mesh number is given by assigning a number to each mesh in the order of N characters, with the minimum longitude and minimum latitude mesh as the reference mesh. Further, a version number as new and old information added each time the map data is revised is added to the map data for each mesh.

  In the present embodiment, the configuration is shown in which the version number added each time the map data is revised is added for each mesh. However, the present invention is not limited to this. As long as information indicating the timing at which individual meshes are updated is added to each mesh, not only the version number but also information on the update date and the like may be added.

  Here, how to handle data of a shape point sequence representing a graphic element in road data, background data, etc. will be described. Note that the graphic element indicates a unit of a unit such as a road, facility, or terrain displayed as a graphic on the map. For example, a graphic element is a section of road, a facility, a section of terrain, or the like. In addition, the shape point sequence referred to here is a coordinate sequence indicating the shape of a graphic element. For example, in the case of a road shape, it is a coordinate sequence of the start and end nodes and segments of a road link, and in the case of a facility shape or terrain, it is a coordinate sequence corresponding to a line indicating the facility, terrain, or the like.

  Since the shape point sequence data is part of the map data, the shape point sequence data is also managed in mesh units. Hereinafter, the shape point sequence of the road A on a certain mesh will be described as an example. In addition, as shown in FIG. 4, the shape point sequence of the road A includes the start node (C in FIG. 4) and the end node (D in FIG. 4) and four segments (FIG. 4). It shall consist of 6 points with E1-E4) in the middle. FIG. 4 is a schematic diagram showing a later-described reference point on the mesh, a shape point sequence of the road A, and a representative point of the road A.

  First, the lower left corner point (F in the figure) of the mesh is set as a base point (hereinafter referred to as a reference point) for representing a later-described representative point in relative coordinates. Here, the lower left corner point of the mesh corresponds to the reference point of the claims. Further, since one mesh is 32768 × 32768 pixels, any point on the mesh can be expressed as long as the relative coordinate from the reference point is 2 bytes (16 bits). Therefore, the relative coordinates of the representative point from the reference point (hereinafter, the relative coordinates of the representative point) are expressed in 2 bytes. For road A, a representative point for road A is set at a position on the mesh, which is a base point that can represent all relative coordinates of the above-described six shape point sequences in 1 byte. (G in FIG. 4). In addition, 2 bytes here are equivalent to the predetermined bit number of a claim, and 1 byte is equivalent to the compression bit number of a claim.

  Next, a representative point setting method will be described. Here, an example in which a numerical value of 0 or less is expressed by 1 byte will be described. The case where a numerical value of 0 or less is expressed by one byte indicates a case where a negative numerical value is also expressed by a so-called signed numerical expression. In addition, as a numerical expression with a sign, for example, a sign bit may be added to express a positive / negative value to express a numerical value of −127 to 127, or a 1's complement expression in a binary number may be used to represent − A numerical value of 127 to 127 may be expressed. Alternatively, a numerical value of −128 to 127 may be expressed using a two's complement expression in a binary number, or a numerical value of −127 to 128 may be expressed using an excess N.

  When a numerical value of 0 or less is also expressed by 1 byte, for example, the shape of the road A based on a point (hereinafter, center point) corresponding to the center of the shape point sequence of the road A (that is, each point sequence). A position where all relative coordinates of the point sequence can be expressed by 1 byte is searched. As an example, whether or not it is possible to temporarily set as a representative point in order from the coordinates close to the center point, and to express all relative coordinates of the shape point sequence of the road A with 1 byte using the temporarily set representative point as a base point. And a configuration in which all the relative coordinates of the shape point sequence of the road A can be expressed by 1 byte is set as a representative point. Further, a point corresponding to the center of the shape point sequence of the road A may be set as a representative point.

  In addition, although the structure which sets a representative point based on the center point was shown here, it does not necessarily restrict to this. For example, as a configuration in which a representative point is set by searching for a position where all relative coordinates of the shape point sequence of the road A can be expressed in one byte based on any point in the shape point sequence. Alternatively, a representative point may be set by searching a position where all relative coordinates of the shape point sequence of the road A can be expressed by 1 byte based on other points on the mesh. .

  As described above, when a numerical value of 0 or less is expressed by 1 byte, not only a positive integer and 0 but also a negative integer can be used to express a shape point sequence in relative coordinates. A representative point can be set without being limited to a position where the relative coordinates of each point in the point sequence can be expressed by a numerical value of 0 or more. Therefore, there is an advantage that the degree of freedom of the position for setting the representative point can be increased and the setting of the representative point can be facilitated.

  In the above-described embodiment, the configuration in which only one representative point is set for one graphic element is shown, but the present invention is not necessarily limited thereto. For example, a configuration may be adopted in which a plurality of representative points are set for a graphic element. Further, when a plurality of representative points are set for a graphic element, a plurality of representative points are set for a graphic element that cannot represent all the point sequences of the graphic element with only one representative point in one byte. More preferably.

  In the following, a configuration is described in which a plurality of representative points are set for a graphic element that cannot represent all of each point sequence of a graphic element with one byte by using only one representative point. FIG. 5 is a schematic diagram for explaining an example of representative points set on the mesh. In FIG. 5, the road A will be described as an example. As shown in FIG. 5, the shape point sequence of the road A includes the start end node (C in FIG. 5) and the end node (D in FIG. 5) and four segments (FIG. 5). It shall consist of 6 points with E1-E4) in the middle. In addition, here, it is assumed that there is no position on the mesh where only one representative point can represent the entire shape point sequence of the road A with 1 byte.

  If not all the shape point sequences of the road A can be expressed by 1 byte with only one representative point, the shape point sequence of the road A may be divided and a representative point may be set for each divided portion. When a representative point is set for each segmented portion, a position where all relative coordinates of the shape point sequence in the segmented portion can be expressed by 1 byte is obtained in the same manner as described above and represented. What is necessary is just to set it as the structure which sets a point.

  For example, in the example of FIG. 5, the shape point sequence of the road A is composed of a shape point sequence composed of points of the start node C, segment E1, and segment E2, and points of segment E3, segment E4, and end node D. The shape point sequence is divided into two parts. The relative coordinates of the representative point G1, the segment E3, the segment E4, and the end node D that can represent the relative coordinates of the points of the start node C, the segment E1, and the segment E2 by 1 byte are 1 A representative point G2 that can be expressed in bytes is set. For the representative point G1 and the representative point G2, the relative coordinates from the reference point F are expressed by 2 bytes.

  In the example of FIG. 5, a configuration is shown in which a plurality of nodes and segments are divided into units. However, the configuration is not necessarily limited thereto. For example, a configuration may be used in which a road name or a road type is divided into attribute units. In addition, as a method of determining the classification unit, it is tried as described above whether or not there is a position that can be a representative point for each part that is first classified by the attribute unit, and there is no position that can be a representative point. The portion may be divided in units of a plurality of nodes or segments, and the division unit may be subdivided until a representative point can be set.

  According to the above configuration, even for a graphic element in which not all of the point sequences of the graphic elements can be expressed by 1 byte with only one representative point, all of the point sequences can be expressed by 1 byte. Therefore, according to the above configuration, it is not necessary to cause a situation in which a point sequence that cannot be expressed in 1 byte must be expressed in 2 bytes, and the data size to be handled can be reduced more reliably, and map data can be managed more effectively. Can be easily. In addition, according to the above configuration, for a graphic element that can represent all of each point sequence of a graphic element with only one representative point in 1 byte, a plurality of representative points are not set, so data by adding unnecessary representative points is used. Increase in size can be suppressed.

  In the above-described embodiment, a configuration in which a numerical value of 0 or less is expressed by 1 byte is shown, but the configuration is not necessarily limited thereto. For example, only a numerical value of 0 or more may be expressed by 1 byte. The configuration in which only a numerical value greater than or equal to 0 is expressed by 1 byte indicates a configuration in which only 0 and a positive integer (specifically 0 to 255) are expressed by 1 byte.

  Hereinafter, this configuration will be described with reference to FIG. FIG. 6 is a schematic diagram for explaining an example of representative points set on the mesh. In FIG. 6, the description will be given by taking the road A as an example. As shown in FIG. 6, the shape point sequence of the road A includes the start node (C in FIG. 5) and the end node (D in FIG. 5) of the road link of the road A and four segments (FIG. 5). It shall consist of 6 points with E1-E4) in the middle.

  When only a numerical value greater than or equal to 0 is expressed by 1 byte, it is necessary to express all the relative coordinates of the shape point sequence of the road A by a numerical value greater than or equal to 0. In order to express all the relative coordinates of the shape point sequence of the road A by a numerical value of 0 or more, representative points are set at points closer to the origin of the coordinate plane than any point of the shape point sequence of the road A. There is a need. Here, since the management area belongs to the first quadrant of the coordinate plane, the mesh obtained by dividing the management area also belongs to the first quadrant, and the lower left corner point (that is, the reference point F) is the coordinate on the mesh. The point closest to the origin of the plane.

  Therefore, if a representative point (G3 in FIG. 6) is set to the point closest to the reference point F among the four corner points of the circumscribed rectangle of the road A shape point sequence, any point of the road A shape point sequence is set. It is possible to set a representative point at a point closer to the origin of the coordinate plane, and even when only a numerical value of 0 or more is expressed by 1 byte, all relative coordinates of the shape point sequence of the road A are expressed by a numerical value of 0 or more. Can be expressed. Therefore, the representative point G3 may be set to the point closest to the reference point F among the four corner points of the circumscribed rectangle in the shape point sequence of the road A.

  In a mode in which only a numerical value of 0 or more is expressed by 1 byte, when not all the point sequences of the graphic element can be expressed by 1 byte with only one representative point, the graphic element is displayed in the same manner as described above. What is necessary is just to set it as the structure which classifies and sets a representative point for every divided part.

  In the present embodiment, as described above, the representative points are set at positions on the mesh that can represent all the point sequences of the graphic elements with one byte.

  Then, as the road data of the road A, the representative point for the road A is stored in a data frame in the storage medium 17 with the coordinate value of the relative coordinate from the reference point expressed in 2 bytes. Further, as the road data of the road A, the coordinate points of the relative coordinates from the representative point expressed by 1 byte are stored in the data frame of the above-mentioned six shape point sequences of the road A. Therefore, the navigation device 1 (more specifically, the control device 26) corresponds to the drawing data management device in the claims. When a plurality of representative points are set for the road A, the coordinate values of the relative coordinates of the plurality of representative points are stored in the data frame as the representative points for the road A. The data frame may also store other road data of the road A.

  According to the above configuration, the shape point sequence of the road A can be expressed by 1 byte. Therefore, the shape point sequence of the road A is 1 as compared to the configuration in which the shape point sequence of the road A is expressed by 2 bytes using the reference point F as the base point, as in the case where the representative point G is expressed by the relative coordinates. The data size of road data and background data (that is, drawing data related to drawing display contents) handled in the navigation device 1 can be reduced by the amount that can be expressed in bytes.

  In addition, for all graphic elements on the mesh, all the point sequences representing graphic elements are represented by relative coordinates expressed in 1 byte with the representative point set for each graphic element as a base point. Also good. According to this, for all the graphic elements on the mesh, all the point sequences representing the graphic elements are represented by relative coordinates expressed by the compression bit number based on the representative point set for each graphic element. Therefore, it is possible to further reduce the size of data to be handled and further facilitate the management of drawing data.

  In the above-described embodiment, the configuration in which all the point sequences of the graphic elements are expressed by 1 byte is shown, but the configuration is not necessarily limited thereto. For example, when all of a point sequence of a graphic element cannot be expressed by 1 byte with only one representative point, or when the effect of compressing the data size by expressing with relative coordinates from the representative point is low, the graphic element A configuration may be adopted in which a part of a point or a sequence of points is represented by 2 bytes.

  Further, regarding the data of the shape point sequence representing the graphic elements in the road data, the background data, etc. of the map data held in the storage device of the map center 2, each point sequence representing the graphic elements is based on the representative point. It is good also as a structure represented by the relative coordinate expressed with 1 byte. Therefore, the map center 2 also corresponds to the drawing data management device in the claims.

  Subsequently, the mesh management information will be described. The mesh management information includes, for example, the total number of meshes included in one layer, the absolute coordinates of the lower left corner point of the reference mesh (hereinafter referred to as reference mesh absolute coordinates), and the number of meshes arranged in the east-west longitude direction (hereinafter referred to as longitude). The number of meshes in the direction), the number of meshes arranged in the north-south latitude direction (number of meshes in the latitudinal direction), and the like.

  Returning to FIG. 2, the storage medium 17 also stores various types of facilities, names, addresses, and the like, and these data are used for setting a destination when searching for a route. As the storage medium 17, a CD-ROM or DVD-ROM, a memory card, an HDD, or the like is used.

  For example, a touch switch or a mechanical switch integrated with the display device 23 is used as the operation switch group 18, and various functions (for example, map scale change, menu display selection, destination setting, Route search, route guidance start, display screen change, volume adjustment, map data acquisition update, etc.) are instructed. Further, the operation switch group 18 includes switches for setting a departure place and a destination, and the user operates the switches so that points, facility names, telephone numbers, addresses, etc. registered in advance are operated. From, you can set the starting point and destination.

  The remote controller 19 is provided with a plurality of operation switches (not shown). By inputting various command signals to the control device 26 via the remote control sensor 20 by the switch operation, the control device 26 has the same function as the operation switch group 18. Can be executed.

  The center communication unit 21 communicates with the map center 2 via a network and acquires map data distributed from the map center 2. The center communication unit 21 may be configured to connect to a network through an in-vehicle communication module used for telematics communication such as a DCM (data communication module) mounted on a vehicle, for example, connected via Bluetooth (registered trademark) or the like. The mobile phone may be connected to the network through the mobile phone.

  The external memory 22 is a writable mass storage device such as an HDD. The external memory 22 stores a large amount of data and data that should not be erased even when the power is turned off, and frequently used data is copied from the map data input device 16 and used. . The external memory 22 may be a removable memory having a relatively small storage capacity.

  The display device 23 displays a map for guiding driving of the vehicle, a destination selection screen, and the like, and is capable of full color display, using a liquid crystal display, an organic EL display, a plasma display, or the like. Can be configured.

  The voice recognition unit 24 recognizes voice input from a microphone (not shown) and outputs a control command corresponding to the recognized voice to the control device 26. The control device 26 executes processing according to this control command. The voice output device 25 is constituted by a speaker or the like, and outputs a guidance voice at the time of route guidance based on an instruction from the control device 26.

  The control device 26 is configured as a normal computer, and includes a well-known CPU, ROM, RAM, I / O, and a bus line (all not shown) for connecting these configurations. The control device 26 has a navigation function based on various information input from the position detector 11, the map data input device 16, the operation switch group 18, the remote control sensor 20, the center communication unit 21, the external memory 22, and the voice recognition unit 24. (For example, map scale change processing, menu display selection processing, destination setting processing, route search execution processing, route guidance processing, map matching processing, display screen change processing, volume adjustment processing, etc.) and map data update The process (map data acquisition update process etc.) to perform is performed.

  For example, when a destination is input from the operation switch group 18, the remote control sensor 20, or the voice recognition unit 24, the control device 26 publicizes a plurality of movement paths that satisfy preset conditions such as distance priority and time priority. The route search execution process for searching using the Dijkstra method is performed. In addition, the control device 26 performs route guidance processing for displaying the optimum route to the destination superimposed on the map displayed on the display device 23.

  Further, the control device 26 acquires map data for update (for example, the latest map data) from the map center 2 through communication with the map center 2 by the center communication unit 21, and stores the map data stored in the storage medium 17. Is updated to map data for update acquired from the center 2. The acquisition of the map data for update from the center 2 by the center communication unit 21 may be performed when there is a notification from the map center 2 that the map data has been changed, for example, every week. Or it may be configured to be performed periodically such as every month. Moreover, it is good also as a structure which performs a map data acquisition update process, when the input to the effect of updating map data is performed from the user to input devices, such as the operation switch group 18. FIG.

  The map data acquisition / update process may be configured to acquire and update map data of all meshes included in the management area, or acquire and update map data of some meshes included in the management area. It is good also as a structure.

  As described above, each point sequence representing a graphic element in road data, background data, etc. in map data is expressed in relative coordinates expressed by the compression bit number based on the representative point set for each graphic element. The data size of the map data is more compressed. Therefore, according to the configuration of the present embodiment, when map data is exchanged as described above, it is possible to reduce the communication load and reduce the time taken to acquire and update map data by communication. it can. As a result, map data can be managed more easily with the above configuration.

  Further, the control device 26 performs a process of converting the shape point sequence of the graphic element expressed by the relative coordinates from the representative point to the absolute coordinates in the management area (hereinafter, absolute coordinate conversion process).

  For example, when the position of the facility on the mesh is specified based on the input of the name of the facility at the destination made by the user to the input device such as the operation switch group 18, the control device 26 performs the absolute coordinate conversion process. Do. This is because the name of the destination is associated with absolute coordinates in the management area, whereas the facility on the mesh is represented by relative coordinates from the point set on the mesh. is there.

  In addition, for example, when there is road data extending between two meshes, and only one of the meshes is updated by the map data acquisition update process, the control device 26 performs the absolute coordinate conversion process. The absolute coordinates of the mesh boundary portion of the road data are obtained, and the road data is connected between adjacent meshes. In addition, when a route search is performed across different levels (hereinafter referred to as “levels”) and road data exists between meshes at different levels, the control device 26 performs an absolute coordinate conversion process to perform the conversion of the road data. Find the absolute coordinates of the mesh boundary, connect road data between different levels, and perform route search.

  Here, the absolute coordinate conversion process will be described in detail. First, in the absolute coordinate conversion process, the absolute coordinates of the reference point of the mesh are obtained. The absolute coordinates of the reference point of the mesh may be determined by a known method. For example, the reference mesh absolute coordinates, the number of meshes in the longitude direction and the number of latitude direction meshes in the layer one level above the mesh, the mesh Based on the mesh management information such as the mesh number, the configuration may be obtained in the same manner as the calculation of the representative point absolute position data in Patent Document 1.

  Subsequently, the absolute coordinates of the representative point are obtained based on the absolute coordinates of the reference point of the mesh. Specifically, it is obtained by adding the coordinate value of the relative coordinate of the representative point to the absolute coordinate of the reference point of the mesh. Then, the absolute coordinates of the shape point sequence of the graphic element are obtained based on the obtained absolute coordinates of the representative point. Specifically, the absolute coordinate of each point is obtained by adding the coordinate value of the relative coordinate for the shape point of the graphic element to the absolute coordinate of the representative point.

  As described above, in the absolute coordinate conversion process, based on the absolute coordinates in the management area of the reference point on the mesh, the representative point represented by the relative coordinates from the reference point is converted into the absolute coordinate in the management area. In addition, based on the absolute coordinates in the management area of the representative point obtained by conversion, the point sequence representing the graphic element on the mesh represented by the relative coordinates from the representative point is converted to the absolute coordinates in the management area. Convert to

  In the above-described embodiment, the configuration in which the meshes having the minimum longitude and the minimum latitude are used as the reference mesh and the meshes are sequentially assigned in the N-character order has been described. However, the present invention is not necessarily limited thereto. The mesh number may be a number that is regularly given so that the position in the management area can be specified based on the mesh number, and may be configured to be given in a regular order other than the order of N characters sequentially. . For example, it is good also as a structure provided in the aspect which shows what number it is in the direction of each of the X-axis and the Y-axis from the origin.

  As described above, each point sequence representing a graphic element in road data, background data, etc. in map data is expressed in relative coordinates expressed by the compression bit number based on the representative point set for each graphic element. The data size of the map data is more compressed. Therefore, according to the configuration of the present embodiment, when the calculation process using the map data is performed as described above, it is possible to further reduce the load of the calculation process and suppress the time required for the process. As a result, map data can be managed more easily with the above configuration.

  In the above-described embodiment, the configuration in which the management area belongs to the first quadrant of the coordinate plane is shown, but the configuration is not necessarily limited thereto. For example, if the configuration represents a numerical value of 0 or less by 1 byte, the management area may belong to the second quadrant (x <0, y> 0) of the coordinate plane, or the third quadrant (x <0). , Y <0), or a configuration belonging to the fourth quadrant (x> 0, y <0). In these cases, the reference point corresponding to the lower left corner point of the mesh when the management area belongs to the first quadrant of the coordinate plane is the origin of the coordinate plane among the four corner points of the mesh. What is necessary is just to set it as the structure which sets a near point as a reference point.

  In the above-described embodiment, the configuration in which the reference point is set to the lower left corner point of the mesh is shown, but the present invention is not necessarily limited thereto. For example, as long as a numerical value of 0 or less is expressed by 1 byte, the reference point may be set to the intersection of the diagonal lines of the mesh, or may be set to another point on the mesh.

  In the above-described embodiment, 2 bytes are used as the number of bits representing the relative coordinates of the representative point (corresponding to the predetermined number of bits in the claims), and the relative coordinates of each point in the shape point sequence of the graphic element are represented. Although the configuration using one byte as the number of bits (corresponding to the number of compressed bits in the claims) is shown, it is not necessarily limited to this. As long as the number of bits representing the relative coordinates of each point in the shape point sequence of the graphic element is smaller than the number of bits representing the relative coordinates of the representative point, another number of bits may be used. For example, 8 bits may be used as the number of bits representing the relative coordinates of the representative point, and 4 bits may be used as the number of bits representing the relative coordinates of each point in the shape point sequence of the graphic element.

  In the above-described embodiment, the configuration in which the number of bits representing the relative coordinates of each point in the shape point sequence of the graphic element is set to a single bit number is not necessarily limited thereto. For example, the number of bits expressing the relative coordinates of each point in the shape point sequence of the graphic element may be a non-single bit number. As an example, the relative coordinates of each point may be expressed by the minimum number of bits necessary to express the relative coordinates of each point of the shape point sequence of the graphic element.

In the above-described embodiment, the configuration in which the map data for update is acquired from the map center 2 is shown, but the present invention is not necessarily limited thereto. For example, the map data for update may be acquired from a removable medium such as a flash memory, a CD-ROM, or a DVD-ROM. In this case, the navigation device 1 may be provided with a reading device that reads update data from the removable medium. In the above-described embodiment, the control device 26 of the navigation device 1 serves as the drawing data management device of the claims. The map center 2 has been described as an example, but the present invention is not necessarily limited thereto. As the drawing data management device according to the claim, the data expressed by the number of bits in which the relative coordinate from the representative point of the shape point sequence of the graphic element is smaller than the number of bits expressing the relative coordinate of the representative point from the reference point As long as it is a stored device, a device other than the above-mentioned devices also applies.

  Furthermore, in the above-described embodiment, the configuration in which the present invention is applied to the electronic map drawing data (that is, map data) related to the drawing display contents of the area on the map divided into a plurality of meshes has been described. Not exclusively. For example, the present invention may be applied to drawing data related to drawing display contents of an area divided into a plurality of meshes other than map data, such as drawing data of a facility management chart.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

1 navigation device (drawing data management device), 2 map center (drawing data management device), 11 position detector, 16 map data input device, 17 storage medium, 18 operation switch group, 19 remote control, 20 remote control sensor, 21 center communication Unit, 22 external memory, 23 display device, 24 voice recognition unit, 25 voice output device, 26 control device, 100 map data update system

Claims (14)

While managing the drawing data regarding the drawing display contents of the area divided into a plurality of meshes in units of the mesh,
A drawing data management device representing a sequence of points representing graphic elements on the mesh with relative coordinates based on a representative point set on the mesh,
The region belongs to the first quadrant of the coordinate plane;
The representative point is
It is represented by relative coordinates expressed by a predetermined number of bits with a reference point set at the lower left corner point on the mesh as a base point,
Wherein a position which can be the number of compressed bits is a predetermined small number of bits than the number of bits representing the point sequence of the graphic element, among the points of the four corners of the circumscribed rectangle of the graphic element, the reference Set to the point closest to the point ,
The point sequence is
The drawing data management apparatus is represented by relative coordinates represented by the number of compressed bits with the representative point as a base point, and is represented only by a numerical value of 0 or more by the number of compressed bits . While managing the drawing data regarding the drawing display contents of the area divided into a plurality of meshes in units of the mesh,
A drawing data management device representing a sequence of points representing graphic elements on the mesh with relative coordinates based on a representative point set on the mesh,
The drawing data is drawing data of an electronic map related to drawing display contents of an area on a map divided into a plurality of meshes,
The graphic element is a road on a map,
The representative point is
It is represented by relative coordinates expressed by a predetermined number of bits with a reference point set at a predetermined position on the mesh as a base point,
Is set at a position on the mesh where the point sequence of the graphic element can be expressed with a compressed bit number that is a bit number smaller than the predetermined bit number;
For graphic elements that cannot represent all of the point sequences of graphic elements with only one representative point, the graphic elements are divided into road name units or road type units, and for each divided part The representative point is set,
The point sequence is
The drawing data management apparatus represented by relative coordinates expressed by the number of compressed bits with the representative point as a base point. In claim 1,
The drawing data is drawing data of an electronic map related to drawing display contents of an area on a map divided into a plurality of meshes,
The drawing data management apparatus according to claim 1, wherein the graphic element is at least one of a terrain on a map, a road, and a facility. In claim 2 ,
The drawing data management apparatus, wherein the point sequence also expresses a numerical value of 0 or less depending on the number of compressed bits. In claim 4 ,
The drawing data management apparatus, wherein the representative point is set based on a point corresponding to the center of each point sequence of the graphic element. In claim 5 ,
The drawing data management apparatus, wherein the representative point is set to a point corresponding to the center of each point sequence of the graphic element. In any one of Claims 2 and 4-6 ,
The region belongs to the first quadrant of the coordinate plane,
The drawing data management apparatus, wherein the reference point is set at a lower left corner point of the mesh. In claim 7 ,
The point sequence is expressed only by a numerical value of 0 or more depending on the number of compression bits
The drawing data management apparatus, wherein the representative point is set to a point closest to the reference point among the four corner points of the circumscribed rectangle of the graphic element. In any one of Claims 1-8 ,
The drawing data management apparatus according to claim 1, wherein a plurality of the representative points are set for at least one of the graphic elements on the mesh. In claim 1 or 3 ,
The drawing data management apparatus according to claim 1, wherein a plurality of graphic points are set for graphic elements that cannot represent all of the respective point sequences of graphic elements with the number of compressed bits with only one representative point. In claim 10 ,
For graphic elements that cannot represent all of the point sequences of graphic elements with only one representative point, the graphic elements are segmented, and the representative points are set for each segmented segment. A drawing data management apparatus. According to claim 10 or 1 1,
For all the graphic elements on the mesh, all of the respective point sequences representing the graphic elements are represented by relative coordinates expressed by the number of compression bits based on the representative point set for each graphic element. A drawing data management apparatus characterized by comprising: In any one of claims 1 to 1 2,
The drawing data management apparatus according to claim 1, wherein the compression bit number is a single bit number smaller than the predetermined bit number. According to claim 1 3,
The predetermined number of bits is 2 bytes,
The drawing data management apparatus according to claim 1, wherein the number of compressed bits is 1 byte.

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