JPH07220118A - Terrain display device - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a terrain display device capable of displaying terrain in real time by reducing the number of processing times of three-dimensional digital terrain data composed of mesh. [Configuration] An output display device for displaying three-dimensional terrain, a display processing device for creating a three-dimensional model of terrain in units of planes, and an input instruction device for inputting a terrain range to be displayed,
A data retrieval device for retrieving the terrain data in the range set by the input instruction device and reading the data, a database management device for storing the three-dimensional digital terrain data, and terrain data on grid points as parameters representing the shading situation of the terrain. A conversion device for conversion and a display data storage device for storing the topographical data and the parameters are provided. [Effect] By reducing the number of processes, it is possible to display in real time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention processes a digital terrain data in a terrain display device, such as a flight simulator or a drive simulator, which artificially generates and displays the surrounding terrain by computer graphics, and three-dimensionally processes it. The present invention relates to a terrain display device for displaying terrain in real time and in real time.

[0002]

2. Description of the Related Art In flight simulators and drive simulators, computer graphics are used to simulate and display the surrounding terrain that can be seen from inside the aircraft or inside the vehicle. In addition, in the terrain display in these simulators, a moving image is generated and displayed in order to give a sense of reality and authenticity. An embodiment of a terrain display device that has been conventionally used to generate and display a moving image will be described with reference to FIG. FIG. 16 is a block diagram of a conventional terrain display device. In the figure, a database management device 1 is a device that stores digital terrain data constituted by numerical values of latitude, longitude, and altitude. The input instruction device 2 is a device for setting the area to be displayed. The data search device 3 is a device that searches the database management device 1 for topographical data in an area to be displayed according to the area set by the input instruction device 2 and a predetermined position and direction. The display processing device 4 inputs the terrain data retrieved by the data retrieving device 3, calculates a parameter for determining the degree of shading corresponding to each terrain data, and further determines the surface shape of the terrain by connecting a number of planes. This is an apparatus for modeling using the model shown (hereinafter referred to as a surface model). The output display device 5 inputs the vertex coordinates of the created surface model and erases the plane representing the terrain if it does not appear hidden in the shadow of another plane (hereinafter referred to as hidden surface elimination processing), or the terrain. This is a device for displaying a three-dimensional topography by performing processing (hereinafter referred to as shading processing) for determining the brightness determined by the position of the light source and surrounding environmental conditions on each plane forming the.

Next, the operation of the device shown in FIG. 16 will be described. The database management device 1 stores topographical data composed of numerical data of longitude, latitude, and altitude measured in mesh units. The input instruction device 2 sets the display area of the topographical data according to the instruction input by the user. The data search device 3 searches the database management device 1 for the topographical data of the area required for display, based on the area set by the input instruction device 2 and the position and direction set in advance. . In the display processing device 4, the terrain data retrieved by the data retrieval device 3 is input,
Focusing on certain terrain data, create 6 triangular faces with the terrain data as vertices, calculate the normal vector for each triangular face, and synthesize the 6 normal vectors obtained. By normalizing, it is converted into a parameter that determines the degree of shading corresponding to the data. The above conversion process is repeated for all input terrain data. Further, the display processing device 4 creates a model for realizing the displayed topography on a plane (hereinafter, referred to as modeling), in addition to the conversion into the above-mentioned parameters. To create the above model, it is necessary to approximate the surface of the terrain with polygons. In this case, the number of polygon vertices existing in the three-dimensional space is 4
If the above is allowed, the surface composed of these vertices may not always satisfy the condition of the plane. However, if the number of vertices is limited to three triangles, the surface formed by the three points in the three-dimensional space is always on the same plane, so that the hidden surface processing performed by the output display device can be executed without contradiction. Therefore,
A surface model is created by converting the input terrain composed of n vertices into a plane data structure composed of n-2 triangles (hereinafter referred to as triangle patches). The coordinates of the vertices for each plane in the created surface model are input to the display device clockwise or counterclockwise. The output display device 5 checks from the input vertex coordinates of each plane whether the plane is hidden by another plane, and if hidden, performs hidden surface removal processing and shading processing. And display the 3D terrain. A moving image is generated by repeating these series of operations.

[0004]

As described above, in the simulator, the moving image is used in order to give a realistic sensation or realism. In addition, in order to give the realistic sensation, a real-time and high-quality moving image is generated. Is needed. However, the conventional terrain display device is configured as described above, and when trying to display a terrain having a complicated shape, the terrain is approximated using triangular patches, and therefore is used for approximation. The number of triangular patches becomes enormous, and it takes time because processing is performed for each triangular patch, and each time the screen is updated, conversion to the parameter that represents the degree of shading used for display is repeated, so the number of processing times increases. There was a problem that the increased terrain could not be displayed in real time. In addition, if the number of meshes is simply reduced to reduce the processing time and the number of thinned triangle patches is reduced, there is a problem that a good-quality display screen cannot be obtained. In other words, when a complicated shape such as terrain is displayed using a surface model in a drive simulator or the like, an approximation process that is effective for the terrain and uses a small number of triangular patches is required.

The present invention has been made to solve the above problems, and reduces the number of times of processing three-dimensional digital terrain data composed of meshes and also reduces the number of meshes used for display to approximate the terrain surface. It is an object of the present invention to obtain a terrain display device that reduces the number of triangular patches used in, reduces processing time, and enables high-speed terrain display.

[0006]

In the terrain display device according to the first embodiment of the present invention, terrain data is input from a database management device that stores three-dimensional digital terrain data composed of latitude, longitude and altitude, For each grid point where topographic data exists, form six triangles that include the grid point, calculate the normal vector for each of the six triangles, synthesize the obtained normal vector, and normalize A conversion device for converting into a parameter representing the shaded condition of the terrain at the grid point of interest, and a display data storage device for storing the parameters obtained by the conversion device and the terrain data input from the database management device Is.

In the terrain display apparatus according to the second embodiment, the input terrain data is divided into four mesh units, and the elevation difference is calculated from the maximum value and the minimum value of the elevation data included in the divided mesh. The elevation difference is compared with a threshold value, and if the difference is larger, the elevation difference becomes smaller than the threshold value, or the mesh is repeatedly divided into four parts until the difference reaches a minimum mesh size. Focusing on the data compression device that compresses the data by reducing the number of the data and the data having the quad tree structure (hereinafter referred to as the quad tree structure) and the quad tree structure of the compressed terrain data, the qua
The compressed data search device searches the data required for display by tracing the d Tree structure in the order in which it goes.

Further, in the terrain display apparatus according to the third embodiment, the mesh unit data compressed by the data compression apparatus has a mesh of a size larger than the mesh of interest for the adjacent 8 neighboring meshes. If there is a large size mesh, the terrain data is adjusted by using the terrain data corrected from the large size mesh. further,
For each of the four grid points on each mesh, of the meshes that are in contact with each grid point, by giving the grid point a parameter that represents the shade situation of the terrain corresponding to the largest mesh, A matching device for matching meshes is provided.

[0009]

In the terrain display device according to the first embodiment of the present invention, the conversion device calculates the parameter representing the shadow condition of the terrain surface,
By storing it together with the terrain data in the newly provided display data storage device, it is possible to reduce the number of accesses to the database management device and the number of times the parameters representing the shading condition of the terrain surface are calculated, and high-speed 3D terrain display It can be carried out.

Further, in the terrain display device of the second embodiment, it is determined whether the terrain displayed by the terrain data compression device is a flat surface or an inclined surface, and the flat surface portion is determined. Is displayed with a coarse mesh and the inclined surface is displayed with a dense mesh, thereby compressing the data and enabling high-speed three-dimensional topographic display.

Further, in the terrain display device of the third embodiment, when the sizes of the adjacent meshes are different, the matching device interpolates the data from the terrain data of the large mesh to obtain the data to be used for the matching, and the data is used. By using for display, it is possible to obtain a high-definition three-dimensional topographic image by matching topographic data between adjacent meshes of different sizes.

[0012]

【Example】

Example 1. Embodiment 1 of the present invention will be described with reference to a specific drawing. FIG. 1 is a block diagram of an embodiment of a terrain display device according to the present invention. In the figure, 1,
Reference numerals 2, 3 and 5 are exactly the same as those of the conventional device. 6
Is a conversion device for calculating display parameters, and 7 is a display data storage device for storing topographical data and display parameters. A display processing device 8 is a device having only the hidden surface erasing and shading functions of the display processing device 4 in the conventional device shown in FIG. The terrain display device according to the present invention is composed of the above 1-3, 5-8.

FIG. 4 is a flowchart showing the processing procedure of the first embodiment of the present invention. The processing procedure in FIG. 4 will be described below. As shown in FIG. 4, by performing the terrain data input procedure 9, the terrain data is obtained from the database management device 1 storing the terrain data.
By inputting the topographical data into the conversion device 6 and executing the conversion procedure 10, the topographical data is converted into a parameter representing the shaded state of the topography to be displayed. By performing the data storage means 11, it is associated with the terrain data, and the parameters converted in the conversion procedure 10 are stored in the display data storage device 7. Here, the display range is set by the user performing the search instruction input means 12 using the input instruction device 2. The topographical data is read by performing the data search procedure 13 according to the setting. By performing the display processing procedure 14, a surface model in which the shape of the terrain surface is expressed using a plane is created from the terrain data input to the display processing device 8 and the parameters representing the shading situation of the terrain. When the coordinates of each vertex of the created surface model are input to the output display device 5, the output display procedure 15 is performed and the three-dimensional topography is displayed. Further, in the simulator to which this device is applied, the data search range setting means 16 is performed to automatically calculate the range of data to be displayed next according to the moving direction, and the data is searched from the display data storage device according to the range. To do. After that, the data search means 13 to the data search range setting means 1
Repeat 6 Next, the operation of the conversion procedure 10 will be described. As shown in the flowchart of FIG. 5, the data input processing means 17 is used to input the terrain data from the database management device 1 in which the terrain data is stored in the device of FIG. Paying attention to one grid point of the input topographical data, the triangle forming procedure 18 is performed, and six triangles are created with the grid point as a vertex. The normal vector calculation procedure 19 is performed for each created triangle, and six normal vectors for each triangle corresponding to one vertex are obtained. By performing the normal vector synthesizing procedure 20 and the normal vector normalizing procedure 21 on the obtained six normal vectors,
The terrain data on one focused grid point is converted into a parameter representing the shaded state of the terrain to be displayed. 17 above
The operations up to 21 are performed on the data on all the input grid points, and the process end determination procedure 22 is performed to complete the conversion into parameters.

Example 2. Next, as a second embodiment of the present invention, a case where a compression device is used to reduce the terrain data and the parameter representing the shaded state of the displayed terrain will be described in detail with reference to the drawings. FIG. 2 is a block diagram of an embodiment of the terrain display device according to the present invention. In the figure, reference numerals 1, 2, and 5 are the same as those of the conventional device. Further, 6 to 8 are exactly the same as the device described in the first embodiment. Reference numeral 23 is a data compression device for compressing the terrain data, and 24 is a compressed data retrieval device for retrieving the region data to be displayed from the compressed data. Two
It is composed of 4.

FIG. 6 is a flow chart showing the processing procedure of the second embodiment of the present invention. As shown in FIG. 6, a data compression procedure 25 for compressing terrain data is added to the first embodiment after the conversion processing procedure 10, and a data search procedure is further performed to efficiently search compressed data. The configuration is changed to step 26. Here, the operation of the terrain data compression apparatus will be described. As shown in the flowchart of FIG. 7, in the apparatus of FIG. 2, processing is performed according to each procedure of the conversion apparatus 6 as in the first embodiment.
Next, the compression device data input procedure 27 is performed to input the terrain data and the parameters representing the shaded state of the terrain to be displayed. The division processing procedure 28 is performed and the input terrain range is set to 4
To divide. The altitude difference calculation procedure 29 is performed, the data in each divided range is searched, and the altitude difference is obtained. Next, the altitude difference determination procedure 30 is performed to determine whether the calculated altitude difference is larger than a threshold value. If it is larger, the range is further divided into four, and the work of obtaining the altitude difference and comparing it with the threshold value is recursively performed until the mesh size becomes the minimum or the altitude difference becomes less than or equal to the threshold value. On the other hand, when the altitude difference is less than or equal to the threshold value, the lowest layer mesh storage procedure 31 is performed to store the range as the lowest layer range, and the included altitude data is represented by the altitude data at the four corners of the range. . A process end determination procedure 32 for determining division and storage processing for all meshes is performed. If all the ranges are completed, the compression process is terminated, and if there is a range that is not yet completed, By performing the above division and storage procedure on the range, the data is hierarchized (hereinafter referred to as a Quad Tree structure or a Quad Tre structure).
Then, the data compression is completed. FIG. 8 shows an example of the operation of the compression device, and the uppermost hierarchy in FIG. 8 shows the display range.
It is divided into four units of 3, 34, 35 and 36 in units of meshes. First, the altitude difference of the altitude data existing in the range 33 including the data on the boundary of the range 33 is obtained. The obtained altitude difference is compared with the threshold value. Since the obtained altitude difference is larger than the threshold value here, the range 33 is further divided into four, and ranges 37, 38, 39 and 40 are created. In this layer, first, the difference in altitude for the range 37 is obtained and compared with the threshold value. As a result, since it is larger than the threshold value, the range 37 is again divided into four, and the ranges 41, 42, and 4 are divided.
Make 3,44. And the ranges 41, 42, 43, 44
Is the minimum mesh size, so range 4
The topographical data at each of the four corners 1, 42, 43, and 44 are stored in the storage device as compressed topographical data. By repeating these comparison operations, compressed data 46 can be created as shown in FIG. 14 from the terrain data 45 read with the minimum mesh size in FIG. Next, the operation of the compressed data search device will be described. As shown in the flowchart of FIG. 9, in the apparatus of FIG. 2, processing is performed according to each procedure of the conversion apparatus and the compression apparatus. Next, the compressed data input procedure 47 is performed to input the compressed data having the Quad Tree structure. The input data is subjected to a subdivision determination procedure 48 for determining whether or not it has a lower hierarchy, and when it has a lower hierarchy, a lower layer search procedure 49 for subdividing and performing a search is performed, and no lower hierarchy is provided. In the case of a line, the lowermost layer determination procedure 50 for detecting the data as the lowermost layer data is performed. By performing this on the data having the Quad Tree structure, the Quad Tree is searched in the order in which it passes, and the compressed data is searched. FIG. 10 shows that the terrain data compressed by the compression device has a tree structure, and shows an example of the operation of the compressed data search device. First, the tree root 5
The search starts from 1. First, when the node 52 is examined, since this node is further branched, the branched node 53 is examined. Similarly, the node 53 is branched into the nodes 54, 55, 56 and 57, so that each node will be examined. Nodes 54, 55, 56, 57
Since is a node without branching, the topographical data is read on the mesh grid point corresponding to this node. As described above, the node branching determination is performed using the node 52 → the node 53 → the node 5
4 → node 55 → node 56 → node 57 → node 58 → node 5
9 → node 60 → node 61 → node 62 → node 63 → node 6
4 → node 65 → node 66 → node 67 → node 68 → node 6
9 → node 70 → node 71 in order, and end nodes 54, 55, 56, 57, 58, 59, 60, 6 in each branch.
1, 63, 64, 66, 67, 68, 69, 70, 71
To get The range corresponding to the obtained nodes is the range of the lowest layer of the search target, and ranges 34, 36, 38, 3 shown in FIG.
9, 40, 41, 42, 43, 44, 72, 73, 7
4, 75, 76, 77, 78 are obtained.

Embodiment 3. Next, as a third embodiment of the present invention, a case where the matching device is used to match the terrain data will be described in detail with reference to the drawings. FIG. 3 is a block diagram of an embodiment of the terrain display device according to the present invention. In the figure, reference numerals 1, 2, and 5 are the same as those of the conventional device. Further, 6 to 8, 23 and 24 are exactly the same as the device described in the second embodiment. Reference numeral 79 is a matching device for matching data, and the terrain display device according to the present invention is composed of the above-mentioned 1, 2, 5-8, 23, 24, 79.

FIG. 11 is a flow chart showing the processing procedure of the third embodiment of the present invention. As shown in FIG. 3, a matching procedure 8 for matching the topographical data with the second embodiment described above.
0 is added after the compressed data search procedure 26. Here, the operation of the matching device will be described. 12
As shown in the flowchart of FIG.
Topographical data input procedure 9 and conversion procedure 1 as in the second embodiment
0, the data compression procedure 25 is performed, the data is stored in the display data storage device, the compressed data search procedure 26 is performed, and the retrieved data is input according to the input procedure 81. The terrain data, the mesh size information used at the time of drawing, and the terrain to be displayed. Enter the parameter that represents the shading situation of. A mesh size determination procedure 82 is performed, and it is determined whether or not each of the 8 neighboring meshes has a large size. If there is a large mesh in the vicinity of 8 as a result of the judgment, the terrain data correction procedure 83 is carried out to calculate the data used for matching the data. The topographical data correction processing end determination procedure 84 for determining whether or not the above-described steps 82 to 83 are performed for all meshes is performed, and the matching processing for the entire topographical data is completed. Next, a parameter input procedure 85 representing the shaded state of the terrain is performed to input the parameters. With respect to the input parameters, the maximum mesh detection procedure 86 is performed paying attention to each grid point, and the largest size mesh is detected among all the meshes in contact with each grid point. The parameter correction procedure 87 is performed using the parameter corresponding to the detected mesh to correct the parameter at the grid point of interest. A parameter correction process end determination procedure 88 for determining whether or not all grid points have been performed is performed, and if all grid points have been performed, the parameter correction process is completed. By the above processing procedure, the terrain data and the parameter representing the shaded condition of the displayed terrain are matched. FIG. 15 shows an example of the operation of the matching device, and shows the mesh searched by the data search device. First, regarding the mesh 41, it is examined whether or not there is a mesh of a size larger than itself in the 8 vicinity. Here, the meshes in the 8 neighborhoods are only 42, 43, and 44, and there is no mesh having a size larger than the mesh of interest. Therefore, it is not necessary to perform matching in particular, and the processing is moved to the next mesh. In the next mesh 42, the mesh in the 8 neighborhood is 3
8, 43, 44, 41, and since the mesh 38 has a larger size than itself, data obtained by interpolating from the terrain data on the upper left grid point and the lower left grid point on the mesh 38. Is used to correct the lower right terrain data in the mesh 42. In the next mesh 43, the meshes near 8 are 41, 42, 38,
39, 40, 44, and the meshes 38, 39, 40 are larger than themselves, but the mesh 3
8 has already been corrected, and the mesh 39
And share terrain data, here, using the terrain data on the lower right grid point and the data obtained by interpolating from the terrain data on the lower left grid point in the mesh 40,
The top left terrain data in the mesh 43 is corrected. As described above, the meshes 41, 42, 43, 44, 3
8, 39, 40, 34, 72, 73, 75, 76, 7
7, 78, 74 and 36 are subjected to mesh detection and data correction processing, and the lower right terrain data of the mesh 42, that is, the upper right terrain data of the mesh 43 and the mesh 4
3 lower left terrain data, that is, lower right terrain data of the mesh 44, lower right terrain data of the mesh 38, that is, upper right terrain data of the mesh 39, and lower left terrain data of the mesh 39, that is, lower right terrain of the mesh 40. Data, top right data of the mesh 72, that is, top left data of the mesh 73, top right data of the mesh 75, that is, top left data of the mesh 76,
Topographical data on the upper left of the mesh 78, that is, the mesh 75
A total of eight topographical data of the lower left topographical data and the upper left topographical data of the mesh 74, that is, the lower left topographical data of the mesh 72 are corrected. Next, the parameters representing the shaded condition of the terrain on the grid points are corrected. Here, a case where the mesh 39 is corrected is shown. First, mesh 3
Starting from the upper left grid point of 9, the mesh that is in contact with that grid point is examined, and the parameter that represents the shaded condition of the terrain corresponding to the largest mesh among them is inserted, but the one that touches here is the mesh. 43, 38, 3
9 and 40, of which the larger mesh is mesh 3
8, 39 and 40 have the same size, and only the mesh 43 has a smaller size. In this case, the mesh 39
Use the parameter that represents the shading situation of the terrain of. Next, when the mesh which is in contact with the upper right grid point of the mesh 39 is examined, it is found that the mesh 3 is in contact with this grid point.
Although they are 8, 39, both have the same size, and therefore a parameter indicating the shading condition of the terrain of the mesh 39 is used. Next, when the meshes in contact with the lower right grid point of the mesh 39 are examined, it is the meshes 39, 34, 72, 36 that are in contact with this grid point, and the meshes 34, 3
Since 6 has the same size and is larger than the mesh 39, in this case, a parameter representing the shaded condition of the topography of the mesh 39 is used. When the mesh which is in contact with the lower left grid point of the mesh 39 is examined, it is the meshes 39 and 40 which are in contact with this grid point, but since both have the same size, the parameter representing the shading condition of the terrain of the mesh 39 is set. To use. In this way, the same thing as done for one mesh is corrected for all mesh grid points. As described above, the terrain as a whole is matched by correcting the terrain data on the mesh grid points and the parameters representing the shadow condition of the terrain.

[0018]

Since the present invention is constructed as described above, it has the following effects.

In the first embodiment, the terrain data necessary for display is processed in advance, and the terrain data is changed by storing the terrain data in the display data storage device in association with the terrain data as a parameter indicating the shading condition of the terrain. It is possible to reduce the processing time by omitting the processing performed each time.

In the second embodiment, the number of triangular patches forming the surface model required for display is reduced by compressing the three-dimensional digital terrain data in mesh units, and the display processing is proportional to the number of planes. The time can be shortened.

Furthermore, in the third embodiment, by matching the terrain data of the joint surfaces which are connected by the meshes of different sizes, the terrain data can be smoothly connected and a smooth terrain surface can be expressed, and a fine display can be performed. Obtainable.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a terrain display device according to the present invention.

FIG. 2 is a block diagram showing a second embodiment of the terrain display device according to the present invention.

FIG. 3 is a block diagram showing a third embodiment of a terrain display device according to the present invention.

FIG. 4 is a flowchart showing a processing procedure according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing a procedure of converting into a parameter representing a shaded state of the terrain in the first embodiment of the present invention.

FIG. 6 is a flowchart showing a processing procedure according to the second embodiment of the present invention.

FIG. 7 is a Quad Tre according to the second embodiment of the present invention.
It is a flow chart which shows the processing procedure which compresses topographical data using e.

FIG. 8 is a Quad Tre according to the second embodiment of the present invention.
It is operation | movement explanatory drawing which shows the process sequence which compresses topographical data using e.

FIG. 9 is a flowchart showing a processing procedure for searching for compressed data according to the second embodiment of the present invention.

FIG. 10 is a Quad Tr according to the second embodiment of the present invention.
An operation explanatory diagram showing a processing procedure for searching terrain data having an ee structure, and a Quad Tr possessed by compressed data
It is the figure which showed the ee structure.

FIG. 11 is a flowchart showing a processing procedure according to the third embodiment of the present invention.

FIG. 12 is a flowchart showing a processing procedure for matching compressed data according to the third embodiment of the present invention.

FIG. 13 is a diagram showing conventional mesh data.

FIG. 14 is a diagram showing mesh data after being compressed by Quad Tree processing.

FIG. 15 is an operation explanatory diagram showing a processing procedure for matching compressed data according to the third embodiment of the present invention.

FIG. 16 is a block diagram showing an example of a conventional device.

[Explanation of symbols]

1 Topographic database management device 2 Input instruction device 3 Data retrieval device 4 Display processing device in conventional device 5 Output display device 6 Conversion device 7 Display data storage device 8 Display processing device 9 Topographic data input procedure 10 Conversion procedure 11 Data storage procedure 12 Search Instruction input procedure 13 Data retrieval procedure 14 Display processing procedure 15 Output display procedure 16 Data retrieval range setting procedure 17 Data input processing procedure 18 Triangle formation procedure 19 Normal vector calculation procedure 20 Normal vector synthesis procedure 21 Normal vector normalization procedure 22 Processing end determination procedure 23 Data compression device 24 Compressed data retrieval device 25 Compression processing procedure 26 Compressed data retrieval procedure 27 Compressor data input procedure 28 Division processing procedure 29 Altitude difference calculation procedure 30 Altitude difference determination procedure 31 Bottom layer mesh storage procedure 32 Processing Termination judge 33 Upper left range when the display range is divided into 34 34 Upper right range when the display range is divided into 35 35 Lower right range when the display range is divided into 36 36 When the display range is divided into 4 Lower left range 37 Upper left range when the range 33 is divided into 38 38 Upper right range when the range 33 is divided into 39 39 Lower right range when the range 33 is divided into 40 40 Lower left when the range 33 is divided into 4 Range 41 upper left range when the range 37 is divided into 42 42 upper right range when the range 37 is divided into 43 43 lower right range when the range 37 is divided into 4 44 lower left when the range 37 is divided into 4 Range 45 Conventional data by minimum mesh size 46 Data after compression by Quad Tree processing 47 Compressed data input procedure 48 Subdivision determination procedure 49 Lower layer search procedure 50 Lower layer determination procedure 51 Nodal points corresponding to display range 52 Nodal points corresponding to range 33 Nodal points corresponding to range 37 54 Nodal points corresponding to range 41 55 Nodal points corresponding to range 42 Nodal points corresponding to range 43 Nodal point 57 corresponding to range 45 No. 58 Nodal point corresponding to range 38 Nodal point 59 corresponding to range 39 Nodal point 60 corresponding to range 40 Nodal point 62 corresponding to range 34 Nodal point 63 corresponding to range 35 Node 64 corresponding to the upper left range divided into 4 64 lower part of the range 35 into which the range 35 is further divided into 4 65 Node corresponding to the upper right range 65 into which the range 35 is divided into 4 Nodes corresponding to the lower range 66 The range corresponding to the node 65 is divided into four, and the range corresponding to the upper left range 67 The range corresponding to the node 65 The node 68 corresponding to the divided upper right range 68 The range corresponding to the node 65 is divided into 4 nodes corresponding to the lower right range 69 The range corresponding to the node 65 is divided into 4 nodes corresponding to the lower left range 70 The range 35 The lower right range divided into 4 is further divided into 4 lower left nodes corresponding to the range 71 The nodes corresponding to the range 36 72 The upper left range when the range 35 is divided into 4 73 The upper right range when the range 35 is divided into 4 74 Lower left range when the range 35 is divided into 4 75 Upper left range obtained by dividing the lower right range obtained by dividing the range 35 into 4 76 Upper right range obtained by further dividing the lower right range obtained by dividing the range 35 into 4 77 Lower right range obtained by further dividing the lower right range obtained by dividing the range 35 into 4 78 Lower left obtained by further dividing the lower right range obtained by dividing the range 35 into 4 79 Matching device 80 Compressed data Data matching procedure 81 Mesh information input procedure 82 Mesh size judgment procedure 83 Topographic data correction procedure 84 Topographic data correction processing end judgment procedure 85 Parameter input procedure showing the terrain shading situation 86 Maximum mesh detection procedure 87 Parameter showing the terrain shading situation Correction Procedure 88 Matching Process End Judgment Procedure

Claims (3)

[Claims] 1. A database management device that stores digital terrain data composed of numerical values of latitude, longitude, and altitude, and terrain data input from the database management device to determine the degree of shading on the terrain surface required for display. A conversion device for converting into a parameter to represent, a display data storage device for storing the terrain data input from the database management device and the parameter from the conversion device, an input instruction device for setting a region to be displayed, and the input instruction device. Enter the topographic data of the set area and the geographic data of the area to be displayed according to the preset position and direction from the display data storage device, and enter the retrieved topographical data, and add a plane to the topographical data. Display processing device for creating a three-dimensional model of a terrain surface by pasting, and the display processing device A terrain display device characterized by being configured with an output display device for inputting the vertex coordinates of the shape model created in, and displaying it as three-dimensional terrain. 2. A database management device that stores digital terrain data composed of numerical values of latitude, longitude, and altitude, and terrain data is input from the database management device to determine the degree of shading on the terrain surface required for display. A conversion device for converting into a parameter to represent, a data compression device for compressing the terrain data input from the database management device,
A display data storage device for storing the terrain data compressed by the data compression device and the parameters from the conversion device, an input instruction device for setting an area to be displayed, and an area set by the input instruction device are set in advance. A compressed data retrieval device that retrieves topographical data of an area to be displayed according to the placed position and orientation from the compressed data stored in the display data storage device, and the vertex coordinates of the retrieved topographical data are input, and a plane is added to the topography data. It is characterized by comprising a display processing device for creating a three-dimensional shape model of the terrain surface by pasting and an output display device for inputting the shape model created by the display processing device and displaying it as three-dimensional terrain. Terrain display device. 3. A database management device that stores digital terrain data composed of numerical values of latitude, longitude, and altitude, and terrain data is input from the database management device to determine the degree of shading on the terrain surface required for display. A conversion device for converting into a parameter to represent, a data compression device for compressing the terrain data input from the database management device,
A display data storage device for storing the terrain data compressed by the data compression device and parameters corresponding to the data from the conversion device, an input instruction device for setting a region to be displayed, and an area set by the input instruction device. A compressed data retrieval device for retrieving topographical data of an area to be displayed according to a preset position and orientation from the compressed data stored in the display data storage device, and a data matching device for matching the compressed data , Input the terrain data that has been searched and matched, and attach a plane to the terrain data to create a three-dimensional shape model of the terrain surface, and input the shape model created by the display processing device. , A terrain display device comprising an output display device for displaying as three-dimensional terrain.