JP2006084184A - Three-dimensional gis navigation method, three-dimensional gis navigation server and three-dimensional gis navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional GIS navigation method or the like reducing data quantity, while securing visibility of an image necessary for navigation, in consideration of information balance optimum for a user to recognize a traveling direction, a land mark or the like. <P>SOLUTION: This method for delivering successively static images showing three-dimensional scenery of an individual spot on a route to a destination in response to a navigation request from a client has processes of: selecting static images at fixed distance intervals on a road and static images at fixed angle intervals at a crossing; thinning out the static images within a range wherein utilization is not impeded; and changing a static image quality corresponding to importance exerting an influence on visibility. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a three-dimensional GIS navigation method, a three-dimensional GIS navigation server, and a three-dimensional GIS navigation system for providing a three-dimensional GIS (Geographical Information System) navigation to a mobile phone having a poor graphic function.

  In recent years, three-dimensional GIS is expected to be used in various fields, and some of them are being put into practical use. As one promising application, a navigation system that displays a three-dimensional landscape along a route to a destination on a mobile phone possessed by a pedestrian is considered. However, since the 3D GIS basic data requires enormous arithmetic processing at the time of graphic development, it is very difficult to process it with a mobile phone having a poor graphic function.

  On the other hand, mobile terminals such as mobile phones have recently become smaller, higher performance and more multifunctional. Mainly mobile phones continue to improve significantly year by year. With regard to visual expression, recent mobile phones have become increasingly colored, larger, and higher in image quality, enabling high-performance and versatile expression. Speaking of basic still images and moving images, high-quality expression is possible and it is used for many purposes.

  However, current cellular phones are not suitable for three-dimensional graphics expression using a large amount of spatial data because of comprehensive function restrictions including CPU capability and storage capacity. In addition, since there is a difference in the performance of the three-dimensional graphics engine, display area, and number of colors for each mobile phone, a problem depending on the terminal, such as an operation speed significantly different depending on the terminal, occurs. Therefore, it is extremely difficult to render a large number of buildings and roads in a wide range and reproduce them with animation by adopting a three-dimensional GIS system in the current mobile phone.

Therefore, it is realistic to rely on the server for rendering processing using a large amount of spatial data, and to realize 3D animation using still images sent from the server as materials for mobile phones, and several methods have already been proposed. ing. For example, in Patent Document 1, a user's current location information and destination information are received, a route connecting the current location and the destination is calculated, and a plurality of still images at different points on the route or different sizes are displayed on a mobile phone. A technique for distributing and displaying is disclosed.
JP 2004-69423 A

  As described above, it has already been proposed to realize navigation of 3D landscapes on mobile phones with poor graphic functions by distributing and displaying still images on mobile phones, but how to determine the still images to be distributed However, there is a case where the amount of data is increased in practical use, and transmission may be difficult in a limited band of a cellular phone. For example, when distributing still images created at equal intervals along a route to a mobile phone, if the interval is set small to ensure visibility, the amount of data increases, and a response is required for transmission over a narrowband mobile line. The effect on time is inevitable. Also, when transmitting multiple still images from the viewpoint of transmission efficiency and response time reduction, the number of still images that can be held at one time is limited due to the limited memory capacity of mobile phones. There is also a problem that the number of transmissions increases.

  The present invention has been proposed in view of the above-described conventional problems, and the purpose of the present invention is necessary for navigation in consideration of an optimal information balance for the user to recognize the traveling direction and landmarks. Another object of the present invention is to provide a three-dimensional GIS navigation method, a three-dimensional GIS navigation server, and a three-dimensional GIS navigation system that can reduce the amount of data while ensuring the visibility of various images.

  In order to solve the above-described problems, according to the present invention, as described in claim 1, in response to a navigation request from a client, a stationary view showing a three-dimensional landscape of individual points on a route to a destination A method of sequentially distributing images, a step of selecting a still image at a certain distance interval on the road and a still image of a certain angle interval at an intersection, and a step of thinning out a still image within a range that does not hinder use, And a step of changing the image quality of the still image in accordance with the degree of importance that affects the visibility. Thereby, the amount of data can be reduced while ensuring the visibility of images necessary for navigation.

  Further, as described in claim 2, it is possible to perform still image thinning according to the ratio of the total distance of the section roads and the number of still images. Thereby, it is possible to perform basic thinning on still images on the road.

  According to a third aspect of the present invention, still images can be thinned out in accordance with the ratio of the traveling direction change angle at the intersection and the number of still images. As a result, it is possible to perform basic thinning on the still image at the intersection.

  Further, as described in claim 4, it is possible to avoid thinning out still images at important points that affect visibility. Thereby, the fall of the visibility of the image resulting from thinning can be prevented.

  In addition, as described in claim 5, among the still images that have not been thinned out, it is possible to reduce the image quality of still images other than important portions that affect visibility. Thereby, the amount of data can be reduced while ensuring the visibility of images necessary for navigation.

  In addition, as described in claim 6, the important point is the start point, the end point, immediately before the change of the traveling direction, the first and second images in the intersection, or the still image of the landmark It can be. As a result, it is possible to give a specific reference for an important part that affects the visibility.

  In addition, as described in claim 7, in response to a navigation request from a client, the device sequentially delivers a still image showing a three-dimensional landscape of each point on the route to the destination, on the road A means for selecting a still image at a certain distance interval and a still image at a certain angle interval at an intersection, a means for thinning out a still image within a range that does not hinder use, and a still image according to the importance that affects visibility It is possible to configure as a three-dimensional GIS navigation server provided with a means for changing the image quality.

  In addition, as described in claim 8, a three-dimensional landscape of a client having a wireless communication function possessed by a user and individual points on a route to a destination in response to a navigation request from the client. The still images shown are distributed in sequence, and for the still images to be distributed, means for selecting still images at constant distance intervals on the road and still images at constant angle intervals at intersections, and thinning out still images within a range that does not hinder use It can be configured as a three-dimensional GIS navigation system comprising means and a three-dimensional GIS navigation server having means for changing the image quality of a still image according to the importance that affects visibility.

  In the present invention, as a navigation image to be distributed to the client, by thinning out and changing the image quality of a still image at a fixed distance interval on the road and a still image at a fixed angle interval at the intersection, The effect of being able to reduce the amount of data while ensuring visibility, speeding up the response time when transmitting over a narrowband mobile line, and reducing the number of transmissions when transmitting multiple still images at once There is.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a three-dimensional GIS navigation system according to an embodiment of the present invention. In FIG. 1, a 3D GIS navigation system includes a 3D GIS navigation server 1 that creates a still image for navigation based on 3D GIS information and distributes it via the network 2, and a base connected to the network 2. The station 3 is composed of a client 4 such as a mobile phone held by the user.

  The three-dimensional GIS navigation server 1 creates animation data in advance based on the information stored in the GIS database 12 and stores the created animation data in the animation data storage unit 13 and the client 4 via the network 2. A data transmission / reception unit 14 that receives a navigation request from the client 4 and transmits a still image for navigation to the client 4, and a navigation data creation unit 15 that generates navigation data in response to the navigation request from the client 4. And a decimation / image quality changing unit 16 for decimation / image quality change within a range that does not interfere with the user for navigation data still images created by the navigation data creation unit 15; And a fixed object insertion unit 17 adds a fixed object, such as captions and symbols for made navigation to a still image of.

  The animation data creation unit 11 includes a moving image generation unit 111 that generates a moving image of a three-dimensional landscape based on information stored in the GIS database 12, and a still image extraction unit 112 that extracts a still image from the generated moving image.

  The GIS database 12 includes road network information 121 indicating road connection relationships, road shape information 122 indicating road shapes, building shape information 123 indicating the shapes of buildings existing around the road, building outer walls, and the like. It includes building attribute information 124 indicating attributes, and landmark information 125 indicating buildings that can be highly visible landmarks.

  The navigation data creation unit 15 includes a route information analysis unit 151 that analyzes a route using the road network information 121 of the GIS database 12 based on the current location information and the destination information acquired from the client 4, and a route information analysis unit 151 that follows the analyzed route. A still image selection unit 152 that selects all the still images.

  The thinning / image quality changing unit 16 determines a thinning interval according to the total road distance and the ratio of the number of still images or the rate of change in the direction of travel of the intersection and the ratio of the number of still images. , Excluding still images at important locations that are not to be thinned out, thinning location determination / determination unit 162 that determines locations to be thinned out, thinning processing unit 163 that performs thinning processing, and important locations among still images that have not been thinned out An image quality change determination / determination unit 164 that determines and determines a portion that is not an image quality change target, and an image quality change processing unit 165 that executes image quality change processing.

  The fixed object insertion unit 17 determines a position and a traveling direction for each still image from the coordinate data based on the route information analysis unit 171 that analyzes the route using the road network information 121 of the GIS database 12 and the route analysis result. , A caption / symbol insertion unit 172 for adding a caption / symbol to the position / direction of travel.

  The operation of the above embodiment will be described below.

  FIG. 2 is a flowchart showing processing of the three-dimensional GIS navigation server 1.

  First, creation of animation data as a still image material to be provided at the time of navigation will be described as a process before the navigation to the client 4 is performed.

  The animation generation unit 111 of the animation data creation unit 11 performs rendering processing on the roads and intersections in the area where the navigation service is performed based on the information stored in the GIS database 12, and displays a 3D space image that displays the scenery of the roads and intersections. A moving image is generated (step S1).

  Next, the still image extracting unit 112 extracts a still image from the moving image generated by the moving image generating unit 111 at regular distance intervals for roads and at regular angular intervals for intersections. Animation data 501 composed of the data 503 is stored in the animation data storage unit 13 (step S2).

  FIG. 3 is a diagram showing a method of extracting still images in animation data creation. As shown in FIG. 3A, moving images 514 and 515 showing a landscape when moving at a constant speed along the forward and backward paths of each road 511. From the moving image 516 showing the landscape when rotated 360 degrees at a constant angular velocity at the intersection 512, still images 517 and 518 are extracted at certain distance intervals for the moving images 514 and 515 on the road 511, and the moving image of the intersection 512 is extracted. For 516, still images 519 are extracted at regular angular intervals. Reference numeral 513 denotes a building existing around the road 511.

  (B) shows in more detail the extraction of still images on a straight road, and still images 517 are extracted from the moving image 514 of the road 511 at regular intervals. Note that the interval at which the still images 517 are extracted is not so wide, but is dealt with by thinning out still images of portions that do not have a problem in visibility by subsequent thinning-out processing. This is because when a still image is extracted at a wide interval from the beginning, an error between the still image at the movement start point and the end point and the actual landscape increases.

  (C) shows the extraction of still images at intersections in more detail, and still images 519 are extracted from the moving image 516 at the intersection 512 at regular angular intervals. It should be noted that the moving image 516 at the intersection 512 can be unified with the starting point of true north so that the extraction process of the still image 519 can be standardized. In addition, the angle interval for extracting the still images 519 is not so wide, and the still image of the portion having no problem in visibility is thinned out by the subsequent thinning process. This is because, when still images are extracted at wide angular intervals from the beginning, the connection of the landscape at the time of turning left and right becomes difficult to understand, and it is not possible to accurately tell how far the turn is made.

  Next, returning to FIG. 2, processing for performing navigation on the client 4 will be described.

  When there is a navigation request from the client 4 via the data transmission / reception unit 14 (step S3), the route information analysis unit 151 of the navigation data creation unit 15 uses the GIS database based on the current location information and destination information included in the request. The route information combining roads and intersections is analyzed using the 12 road network information 121 (step S4).

  Next, the still image selection unit 152 selects all the still images along the route information from the continuous still images for each road and intersection, and outputs a route still image list file 504 in which the still image identification information is listed ( Step S5).

  FIG. 4 is a diagram showing a method of selecting a still image in creating navigation data. In FIG. 4A, when a road 520 goes straight and turns right onto a road 521 at an intersection 512, a plurality of still images 517 about the road and the intersection are displayed. From 518 and 519, all the still images 522 and 524 belonging to the traveling direction are selected for the road, and all the still images 523 in the angle range that changes with the right turn are selected for the intersection.

  (B) shows in more detail the selection of still images on a straight road, and selects all of the still images 522 along the traveling direction of the road 520. (C) shows in more detail the selection of still images at the intersection, and all the still images 523 existing within the angle change range from the direction 525 to the direction 526 accompanying the right turn at the intersection are selected.

  Next, returning to FIG. 2, the thinning / image quality changing unit 16 thins out the still images listed in the root still image list file 504 within a range that does not hinder the user, and according to the importance. The image quality is changed (image quality is lowered), the still image that has been thinned out is excluded, and a new root still image list file 505 reflecting the identification information of the still image whose image quality has been changed is output (step S6). Details of the processing of the thinning / image quality changing unit 16 will be described later.

  Next, the route information analysis unit 171 of the fixed object insertion unit 17 analyzes the route information using the road network information 121 of the GIS database 12 and adds information for inserting a caption for navigation and a symbol indicating a traveling direction. Obtain (step S7).

  Next, the caption / symbol insertion unit 172 determines the position / travel direction for each still image from the coordinate data (step S8), determines the caption / symbol for the position / travel direction (step S9), and determines the caption / symbol. A control file 507 including information indicating contents, insertion position, and the like is created (step S10).

  The data transmitter / receiver 14 transmits the corresponding still image, caption / symbol data 506, and control file 507 to the client 4 via the network 2 (step S11).

  In the client 4 that has acquired the information, the still image, the caption, and the symbol are combined and displayed based on the control information in the control file 507, and the user compares the displayed still image with the surrounding landscape, Determine the direction of travel using captions and symbols as reference information. When the user recognizes the current display image and performs a predetermined key operation for requesting the next image, the next still image or the like along the route information is transmitted. In this case, still images or the like may be transmitted each time, or a plurality of still images or the like are transmitted to the client 4 in advance as shown in FIG. It is possible to change over and discard still images that are no longer needed. With this prefetching, it is possible to secure terminal responsiveness with little delay when using walking.

  FIG. 6 is a flowchart showing the processing of the thinning / image quality changing unit 16 (details of step S6 in FIG. 2).

  First, the thinning interval determination / determination unit 161 inputs the route still image list file 504 (step S21), and then inputs the road network information 121 from the GIS database 12 (step S22).

  Next, the thinning interval determination / determination unit 161 determines and determines the thinning interval based on the ratio of the total distance of the section road and the number of still images (step S23), and the change angle of the traveling direction at the intersection and the ratio of the number of still images The thinning interval is determined and determined (step S24).

  Next, the thinning point determination / determination unit 162 performs still image of important points that are not thinned, for example, the start point, the end point, immediately before the change of the traveling direction, the first and second sheets in the intersection, the landmark, etc. Is determined and determined (step S25).

  FIG. 7 is a diagram showing an example of the determination of thinning by the still image interval on the straight path. However, when the continuous still images 528 along the road 527 have a certain interval as shown in FIG. The determination unit 161 determines that it is not necessary to perform thinning, and determines that thinning is necessary when the interval between successive still images 530 along the road 529 is narrow as shown in FIG. Decide whether to thin out. In other words, if the interval between still images is a certain distance, there is no need to perform decimation, and conversely, if you decimate, you will not be able to understand the connection between the landscapes in the front and rear images, which will hinder navigation. is there. On the other hand, when the interval between still images is short, if all the still images are used, an enormous amount of data is obtained and it is difficult to perform processing at high speed.

  FIG. 8 is a diagram illustrating an example of thinning out still images on a straight path, and it is determined that the intervals between the still images 531 to 539 extracted at regular intervals (for example, every 10 meters) are short, and every other still image 532 is displayed. In this example, 534, 536, and 538 are thinned out. In addition, examples of remaining still images 531, 533, and 535 are also shown. For example, in the case of still images extracted at an interval of 10 meters, if two or more are thinned out continuously, the distance between the still images will be too wide, and the connection (continuity) of the landscape will not be understood. I try to thin out every other sheet.

  On the other hand, the thinning interval determination / determination unit 161 does not perform thinning for a still image at a predetermined position determined as an important point by the thinning point determination / determination unit 162. The first is a still image immediately after going straight. As shown in FIG. 9, if straight running is started from the still image 540, the still image 540 is not thinned from the original. The subsequent still image 541 is not subject to thinning. This is to make the user's perception in the traveling direction more reliable for a still image immediately after starting straight ahead.

  In addition, the second specific position where thinning is not performed is a still image immediately before the direction of travel changes in a right or left turn along the road, and a place where a right or left turn along the road occurs based on the analysis result of the route information. The still image immediately before that is not specified.

  FIG. 10A shows a case where thinning is performed in accordance with the principle when the vehicle goes straight from point A, turns right at point B and proceeds to point C, and the still image 543 immediately before turning right at point B is thinned out. ing. In this case, since the still image 542 is displayed to the user immediately before turning right at the point B, the connection with the still image 544 at the point B becomes difficult to understand. Therefore, as shown in (b), the still image 543 immediately before turning right at the point B is not subject to thinning. As a result, the connection with the subsequent still image 544 becomes easy to understand, and smooth navigation can be performed.

  FIG. 11 is a diagram illustrating an example of thinning out still images at an intersection. If the vehicle travels straight from point A, turns right at point B and proceeds to point C, the change direction of the traveling direction at the intersection of point B is within the range of change angles. Among the still images 546 to 549 selected as existing, the first still image 546, the subsequent still image 547, and the last still image 549 are left, and the other still images 548 are targeted for thinning. Accordingly, a small angle change occurs between the still image 546 and the still image 547, and a large angle change occurs between the still image 547 and the still image 549.

  This allows the user to fully recognize the change in the direction of travel without using all the still images with a fixed angular interval, so that a predetermined number of images are thinned out in order to reduce the amount of data. Since the first change in the direction of travel should be clearly recognized by the user, the still image following the first still image is not thinned out.

  Next, returning to FIG. 6, the thinning-out processing unit 163 performs the thinning-out processing according to the thinning-out interval and the thinning-out location determined by the thinning-out interval determination / determination unit 161 and the thinning-out location determination / determination unit 162 (step S26). . This is done by deleting the description of the identification information of the corresponding still image from the root still image list file 504.

  Next, the image quality change determination / determination unit 164 determines and determines still images that have not been thinned out and are not thinned after the thinning process is finished (step S27), and the image quality change processing unit 165 does not have important points. The image quality is changed with respect to the still image stored in the animation data storage unit 13 for the still image that is not present (step S28). It should be noted that still images whose image quality has been changed in advance may be prepared for all still images and selected.

  FIG. 12 is a diagram showing an example of the image quality of a still image at the start point. The image quality of the still image 550 at the start point remains in a state where the image quality is not changed in order to show the start location of navigation to the user in an easy-to-understand manner. Keep it as a clear image with high image quality.

  FIG. 13 is a diagram showing an example of the image quality of a still image on a straight path. The user's visibility of the still image 551 at the start point, which is an important point, the next still image 552, and the landmark still image 556 is improved. Although it has high image quality for enhancement, other still images 553, 554, 555, etc. have no change in the direction of travel and do not particularly affect the visibility, so the image quality is lowered to reduce the amount of data. .

  FIG. 14 is a diagram showing an example of the image quality of a still image in a right or left turn along the road. For the still image 557 in front of the point D that makes a left turn, the image quality is changed in order to easily show the change in the traveling direction to the user. A clear image with high image quality is left in a state where no image processing is performed.

  FIG. 15 is a diagram showing an example of the image quality of the still image before the intersection. When the vehicle proceeds straight from the point A, turns right at the point B and proceeds to the point C, the still image 558 before the point B turning right is In order to show the change of the traveling direction to the user in an easy-to-understand manner, a clear image with high image quality is left without changing the image quality.

  FIG. 16 is a diagram illustrating an example of the image quality of a still image at an intersection. When the vehicle travels straight from a point A, turns right at a point B, and proceeds to a point C, the still images 559 to 561 in the intersection of the point B are in progress. In order to indicate to the user in an easy-to-understand manner the degree of change of how much the turn is in the middle of changing direction, a clear image with high image quality without changing the image quality is set.

  Next, returning to FIG. 6, the image quality change processing unit 165 outputs the root still image list file 505 rewritten by the thinning / image quality change (step S29), and the processing is ended.

  In this way, by performing thinning and image quality change processing considering the optimal information balance for the user to recognize the direction of travel, landmarks, etc., the amount of data can be reduced while ensuring the visibility of images necessary for navigation. The response of image display in the client 4 can be accelerated. In addition, the number of transmissions when prefetching a plurality of still images can be reduced.

  The results of actual measurement of the effect of data reduction by thinning out the still image and changing the image quality described above are shown below. The effect of data reduction by about 24% was confirmed.

<Still image before reduction>
-Number of still images: 15-Still image data amount per sheet: Approximately 7kB
(JPEG format with a resolution of 200 x 150 pixels and a compression rate of 60%)
・ Total data volume: 105kB (7kB x 15)
<Still image after reduction>
-Number of still images: 12 (Three thinnings out without any problem)
・ Image quality change: 2 (image quality change due to not being important)
・ Still image data amount per image with changed image quality: Approx. 5kB
(JPEG format with a resolution of 200 x 150 pixels and a compression rate of 35%)
・ Total data amount: 80kB (7kB x 10 sheets + 5kB x 2 sheets)
The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

It is a block diagram of the three-dimensional GIS navigation system concerning one Embodiment of this invention. It is a flowchart which shows the process of a three-dimensional GIS navigation server. It is a figure which shows the method of the still image extraction in animation data creation. It is a figure which shows the method of the still image selection in navigation data creation. It is a figure which shows the example of prefetching, such as a still image. 5 is a flowchart illustrating processing of a thinning / image quality changing unit. It is a figure which shows the example of a judgment of thinning | decimation by the still image space | interval in a straight path. It is a figure which shows the example of the thinning of the still image in a straight path. It is a figure which shows the example of thinning-out immediately after the start of a straight advance. It is a figure which shows the example of the thinning of the still image in the right-left turn along the road. It is a figure which shows the example of the thinning of the still image in an intersection. It is a figure which shows the example of the image quality of the still image in a starting point. It is a figure which shows the example of the image quality of the still image in a straight path. It is a figure which shows the example of the image quality of the still image in the right-left turn along the road. It is a figure which shows the example of the image quality of the still image in front of an intersection. It is a figure which shows the example of the image quality of the still image in an intersection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 3D GIS navigation server 11 Animation data creation part 111 Movie generation part 112 Still image extraction part 12 GIS database 121 Road network information 122 Road shape information 123 Building shape information 124 Building attribute information 125 Landmark information 13 Animation data storage part 14 Data Transmission / reception unit 15 Navigation data creation unit 151 Route information analysis unit 152 Still image selection unit 16 Decimation / image quality change unit 161 Decimation interval determination / determination unit 162 Decimation location determination / determination unit 163 Decimation processing unit 164 Image quality change determination / determination unit 165 Image quality Change processing unit 17 Fixed object insertion unit 171 Route information analysis unit 172 Caption / symbol insertion unit 2 Network 3 Base station 4 Client

Claims (8)

In response to a navigation request from a client, a method of sequentially delivering still images showing a three-dimensional landscape of individual points on a route to a destination,
Selecting still images at constant distance intervals on the road and still images at constant angular intervals at intersections;
A process of thinning out still images in a range that does not hinder use,
A three-dimensional GIS navigation method comprising: a step of changing the image quality of a still image in accordance with an importance level that affects visibility.   The three-dimensional GIS navigation method according to claim 1, wherein thinning of still images is performed in accordance with a ratio between the total distance of section roads and the number of still images.   3. The three-dimensional GIS navigation method according to claim 1, wherein thinning of still images is performed according to a ratio of a change direction of an advancing direction of an intersection and a number of still images.   The three-dimensional GIS navigation method according to any one of claims 1 to 3, wherein thinning of still images at important locations that affect visibility is not performed.   The three-dimensional GIS navigation according to any one of claims 1 to 4, wherein among the still images that have not been thinned out, the image quality of still images other than important portions that affect visibility is reduced. Method.   6. The important point according to any one of claims 4 and 5, wherein the important point is a start point, an end point, immediately before a change in traveling direction, the first and second images in an intersection, or a still image of a landmark. The three-dimensional GIS navigation method according to one item. In response to a navigation request from a client, a device that sequentially delivers still images showing a three-dimensional landscape of each point on the route to the destination,
Means for selecting still images at constant distance intervals on the road and still images at constant angular intervals at intersections;
Means to thin out still images as long as they do not interfere with use,
A three-dimensional GIS navigation server comprising means for changing the image quality of a still image in accordance with the degree of importance that affects visibility. A client having a wireless communication function possessed by the user;
In response to the navigation request from the client, a still image showing a three-dimensional landscape of each point on the route to the destination is sequentially distributed, and the still image to be distributed is at a fixed distance interval on the road and at an intersection. 3D with means for selecting still images at regular angular intervals, means for thinning out still images in a range that does not hinder use, and means for changing the image quality of still images according to the importance that affects visibility A three-dimensional GIS navigation system comprising a GIS navigation server.

Images