CN1953381A

CN1953381A - Management method of high real-time dynamic electronic map

Info

Publication number: CN1953381A
Application number: CNA2006101142880A
Authority: CN
Inventors: 徐恪; 王海洋
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2006-11-03
Filing date: 2006-11-03
Publication date: 2007-04-25
Anticipated expiration: 2026-11-03
Also published as: CN100440790C

Abstract

The invention belongs to the technical field of multimedia graphics processing and dynamic page development, and is characterized in that dynamic electronic map information is divided into three categories: detailed map information, map update information, road condition information, etc. , the map information table including the update time of the map stores the map information; at the same time, the road condition information table is used to store the road condition information; the idea of separating the complete specific information from the modified detailed information reduces the user's time when the map changes dynamically The amount of data downloaded. The invention realizes the dynamic update service of the electronic map with high real-time performance, has the characteristics of strong flexibility, high real-time performance, etc., and effectively reduces the data overhead of the user when downloading the dynamic map.

Description

Management method of high real-time dynamic electronic map

Technical field

High real-time dynamic map management method belongs to multimedia graphics process and dynamic page developmental research field.

Background technology

Along with the high speed development and the progress of current the Internet, the various information services that utilizing Internet is anywhere or anytime provided have become one of part inseparable in people's life.Wherein based on network map, as: traffic information system, Pathfinding system arises automatically.The service of this class by the Internet real-time to the user provide in time, map and traffic information accurately, be subjected to users' favor.And along with popularizing of surfing Internet with cell phone, the user can obtain Map Services more timely by any wireless network services.

But in today that urban transportation and planning are maked rapid progress, comprise highway information in the map, unit information, the continuous change of traffic information etc., not only make the accuracy of electronic chart service of this use static images regular update to be protected and also strengthened ISP's administration overhead, and frequent replacing long electronic chart of relative download time also allows the not abundant cellphone subscriber of bandwidth suffer untold misery.

In order fundamentally to address this problem, need the management method that can finish the electronic chart frequent updating with the small amount of bandwidth cost of design, other application for based on the electronic chart service provide a good subfoundation.

Summary of the invention

The object of the present invention is to provide a kind of dynamic map management method that data updated is separated with update content that is easy to that is applied on the IP network.

The invention is characterized in that it contains following steps successively:

Step (1.): the initialization map server, set up the map updating form, this table content comprises:

Map sequence number: be used for map of unique mark;

The map address: be used for depositing map on map server in the hard disk the memory location;

Place coordinate: be used for depositing this map pairing position coordinates when showing;

Update time: the newness degree that is used for reflecting map;

Wherein, the ground graphic sequence is that 1 map is deposited initial complete map, cartographic information, sequence is that 2 map is deposited and is up-to-date complete map, the place coordinate information of these two figure is (0,0), and the ground graphic sequence is that 3 later clauses and subclauses are not deposited complete cartographic information, but is used for depositing some later detailed information of each change, as: the highway that certain bar is newly opened, set up the traffic information table, comprising: road name: be used for depositing the name information of highway, and congestion state: be used for depositing the congestion state of highway, wherein use letter " R " representative traffic congestion, " Y " representative is slow, and " G " representative is unimpeded;

Step (2.): the initialization client terminal, foundation comprises: the cartographic information table of map sequence number, map address, place coordinate and update time;

Step (3.): whether client presses access network, according to carrying out following steps:

Step (3.1.): check in the cartographic information table whether be empty, ask for complete cartographic information if sky then sends message to map server;

Step (3.2.):, check then in all maps whether update time is consistent with current system time from the update time of that nearest map of current system time if having at least one map in the cartographic information table; Comprise in the local cartographic information table request message of update time the latest if send early than current system time then to map server the update time of this picture, to be used for inquiring whether have available renewal on the map server; Then report an error when the lastest imformation of this picture is later than the current time in system, and remind the current system time of user's modification; Above-mentioned time ratio is accurate to hour;

Step (3.3.): when the user inquires the traffic information of a certain highway by input equipment, client will send the road condition query message that comprises this road name to server;

Step (4.): after server is received request message from the client, successively according to steps of processing:

Step (4.1.): the type of judging this request message:

If the message of asking for additional detailed map information is map sequence number in the described map updating form that 2 map sends to client terminal then;

If the message that the request map upgrades is then at first obtained the update time that comprises in this message, with this of retrieving map updating form update time, and in will showing all update times send to client terminal early than the cartographic information that comprises update time in the message;

If the road conditions solicited message then according to the road name that comprises in the request message, is inquired about the traffic information table, and the congestion condition of correspondence is sent to client terminal;

Step (5.): when server end no matter when which kind of channel receives that cartographic information changes message, at first determine the content of this change and should change the coordinate of geographic location, and the content that will change deposits in the map updating form, then, be in 2 the complete cartographic information to map updating form kind map sequence number this change content integration, and cover this figure, revise update time simultaneously;

Step (6.): after client receives that map that server sends is asked for the answer of message, deposit this cartographic information in this locality, and with update time, relevant informations such as name map write the cartographic information table;

Step (7.): after client is received the map updating message that server sends, according to the arrangement mode of date descending this map lastest imformation being deposited in respectively in the cartographic information table successively the update time in the message;

Step (8.): after client is received the road condition updating message that server sends, directly and show on the map just that with the congestion condition in different this highway sections of color mark, wherein R be red, Y is a yellow, G is a green;

Step (9.): in the time of the client displayed map, respectively with detailed base map initial in the cartographic information table and all map more new situation be presented on the user interface respectively in overlapping mode according to the coordinate that occurs.

The method that we use simulated roadway to change is tested this method, finds under the frequent situation of revising cartographic information, and average each map updating message that produces and may be come from the density of point between 13K ~ 60K, and most result is about 30K.

Map upgrades the message size dot chart and sees Fig. 4

From realize the result, can find that this method is used minimum renewal cost under the situation of cartographic information frequent variations, satisfied the high real-time of data.

Description of drawings

Fig. 1. client map show levels figure;

Fig. 2. the client basic flow sheet;

Fig. 3. the server end basic flow sheet;

Fig. 4. map upgrades the message size dot chart;

Fig. 5. application exemplary plot of the present invention;

Embodiment

Road must be based upon on the basis of relatively large bandwidth cost in the real-time that the frequent variations of traffic information makes the electronic chart service.The dynamic map management method that designs expense of a kind of end is main contribution of the present invention.

The basic thought of this method is, determine an initial map, and, all changes that take place after it are peeled off separately, so based on this figure, when cartographic information changes, user's needs are downloaded through the part of changing, and will be shown on its stack year former figure, and do not need to download again brand-new map, thereby, finished dynamically updating of electronic chart with smaller cost.

Client map show levels figure sees Fig. 1.

In description of the invention, the change that the server section uses the map updating form to write down map, wherein graphic sequence is that 1 map is initial original map, the ground graphic sequence is that 2 map is for to add later up-to-date map with all changes, this map is used to provide to the user who downloads for the first time map and uses, and remaining clauses and subclauses then is used for storing the lastest imformation of map.And carry out the incremental update service when being used for sending request message for client.

The client basic flow sheet is seen Fig. 2.

The server end basic flow sheet is seen Fig. 3

Stronger service also is put into the row of design to traffic information as a kind of real-time, server will provide the congestion situation of corresponding road section for client, and client will not stored the information of this high real-time, put on the map of this machine but it is directly painted, this change will inquire about next time or restart system after disappear.

Application exemplary plot of the present invention is seen Fig. 5.

The present invention can be by being stored in demonstration to former figure respectively in what change data, be implemented under the frequent situation about changing of cartographic information and satisfy the feature of electronic chart service high real-time, and be particularly suitable for the actual demand of the wide characteristics of cell phone system tail band with less flow cost.

Claims

1. The high real-time dynamic electronic map management method is characterized in that the method comprises the following steps successively:

Step (1.): Initialize the map server and create a map update table, which includes:

Map serial number: used to uniquely mark a map;

Map address: used to store the storage location of the map in the hard disk on the map server;

Location coordinates: used to store the location coordinates corresponding to the map when it is displayed;

Update time: used to reflect the newness of the map;

Among them, the map with the map sequence of 1 stores the original complete map and map information, and the map with the sequence of 2 stores the latest complete map. The coordinate information of the two maps is (0, 0), and the map sequence is 3 Subsequent entries do not store complete map information, but are used to store certain detailed information after each change, such as: for a newly opened road, create a road condition information table, including: road name: used to store roads Name information, and congestion status: used to store the congestion status of the highway, where the letter "R" stands for traffic jam, "Y" stands for slow, and "G" stands for smooth;

Step (2.): Initialize the client terminal and create a map information table including: map serial number, map address, location coordinates and update time;

Step (3.): The client performs the following steps according to whether it is connected to the network or not:

Step (3.1.): Check whether it is empty in the map information table, and if it is empty, send a message to the map server to obtain complete map information;

Step (3.2.): If there is at least one map in the map information table, check whether the update time of the map whose update time is closest to the current system time in all maps is consistent with the current system time; if the update time of the picture If it is earlier than the current system time, send a request message containing the latest update time in the local map information table to the map server to ask whether there is an update available on the map server; when the update information of the picture is later than the current system time, an error will be reported , and remind the user to modify the current system time; the above time comparison is accurate to the hour;

Step (3.3.): When the user inquires about the road condition information of a road through the input device, the client will send a road condition query message containing the road name to the server;

Step (4.): When the server receives the request message from the client, it proceeds with the following steps:

Step (4.1.): Determine the type of the request message:

If it is a message for requesting detailed map information, the map whose map serial number is 2 in the map update table is sent to the client terminal;

If it is a message requesting a map update, first obtain the update time included in the message, use the update time to retrieve the map update table, and send all map information in the table whose update time is earlier than the update time contained in the message to the client terminal;

If it is road condition request information, query the road condition information table according to the road name contained in the request message, and send the corresponding congestion status to the client terminal;

Step (5.): When the server receives the map information change message from any channel, first determine the content of the change and the coordinates of the geographical location where the change is located, and store the content of the change in the map update table , and then, integrate the modified content into the complete map information of map update table type map number 2, and cover the map, and modify the update time at the same time;

Step (6.): After the client receives the reply of the map request message sent by the server, it stores the map information locally, and writes the update time, map name and other related information into the map information table;

Step (7.): After the client receives the map update message sent by the server, the map update information is stored in the map information table in descending order of date according to the update time in the message;

Step (8.): After the client receives the traffic update message sent by the server, it directly marks the congestion status of the road section with different colors on the original map, where R is red, Y is yellow, and G is green;

Step (9.): When the client displays the map, the initial detailed base map and all map updates in the map information table are displayed on the user interface in an overlapping manner according to the coordinates that appear.