JP4590770B2 - Cityscape display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional display device of a city landscape used for a car navigation system, a geographic information system (GIS), or the like.
[0002]
[Prior art]
Cityscape display devices that display cityscapes in three dimensions, such as car navigation systems and GIS (geographic information systems), recognize and identify cityscapes realistically and landmarks by displaying as many buildings as possible. It must be displayed as possible. Furthermore, when the viewpoint moves as the vehicle moves, for example, in a car navigation system, the screen scrolls. Therefore, when the screen is scrolled, the display screen is switched in a short time, and smooth to the human eye. It is required to be able to display in a simple form.
[0003]
However, when many buildings are displayed, the time required for generating and displaying an image increases, and the number of frames (number of frames) that can be displayed per second is reduced. For example, a city related to a moving body such as a car navigation system In the landscape display device, display during movement, that is, smooth display during display screen scrolling when the viewpoint moves, is sacrificed. In this way, displaying many buildings and realizing smooth display are the image generation processing capability of the device (for example, the number of frames that can be displayed per second, or the number of polygons that can be drawn per second described later) Etc.), and one or both of them must be sacrificed to some extent and compromise must be made. In the case of emphasizing smooth display during screen scrolling as in a car navigation system, conventionally, as shown in the following two examples, a method of limiting the number of displayed buildings has been adopted.
[0004]
(1) The display area is divided and the area for displaying the building is limited.
In the display by the image display means, the display area is divided into proximity non-display, translucent display, opaque display, and distant non-display from the side closer to the viewpoint.
[0005]
In the proximity non-display area, no buildings are displayed. Since buildings close to the viewpoint are displayed larger, if a building that is too close is displayed, the building group behind is almost invisible, and this is intended to prevent this.
[0006]
No buildings are displayed even in the far non-display area. One of the purposes of providing the far non-display area is to avoid wasting computational resources for remote drawing which is not important in appearance, and this is also a measure for improving the screen display speed. This method is also used as a general method in three-dimensional computer graphics, as is the proximity non-display area.
[0007]
In the translucent display area, the display target building is displayed translucently. One of the purposes of providing a translucent display area is that it is not so far from the viewpoint, so the buildings in this area that might hide the building behind it should not be covered by the building behind it. It is to make it. In addition to semi-transparent display, wire frame display or a combination of wire frame display and semi-transparent display may be used.
[0008]
In the opaque display area, the display target building is displayed opaquely. The above method is often used in the three-dimensional building display of the car navigation system. However, by limiting the building display area, the number of displayed buildings is reduced and the display is easy to see.
[0009]
(2) Select / extract the building for display.
For example, as can be seen in Japanese Patent Application Laid-Open No. 5-250420, the bottom area of a building is used to select and extract a building for display. The purpose presented here is to reduce the scale of the building to be displayed using the bottom area of the building as an index, since the display is complicated and difficult to see when the map is reduced. As a result, it is devised to reduce the number of buildings to be displayed and to make the display easier to see by removing small buildings from the display objects that are not important in appearance.
[0010]
[Problems to be solved by the invention]
Despite such innovations, the following problems still remain when there are many buildings, especially in urban areas.
[0011]
1. Necessary for navigation, for example, because there is no distinction between buildings suitable for landmarks (marker buildings: described later) and buildings suitable for cityscape expression (landscape buildings: described later), and the display priority of both is not set. However, there is a problem that buildings that are not so important in terms of landmarks and landscape expression are displayed, and as a result, it is difficult to identify buildings that are useful as landmarks.
[0012]
2. When a large number of buildings to be displayed are selected, smooth display during screen scrolling is hindered. On the other hand, when emphasizing smooth display, there are problems that many buildings cannot be displayed, landmark buildings are not displayed sufficiently, and the cityscape is not sufficiently well expressed.
[0013]
The present invention has been made to solve the above-described problems. In the cityscape display device, even when the image generation processing capability of the device is limited, the real-time display is maintained, and the screen is scrolled. In addition to realizing a smooth display, the buildings suitable for the landmarks are displayed reliably, and at the same time, the buildings that are appropriately selected for the landscape expression are arranged to improve the reality of the landscape, and The purpose is to display the building easily.
[0014]
[Means for Solving the Problems]
  The cityscape display device according to the present invention selects a landmark building, which is a building suitable as a landmark, and a landscape building, which is a building suitable for landscape expression, using building information having the bottom shape of the building and height information. Building selection means is used to generate a three-dimensional model using the building information for the selected landmark building and landscape building, and the selection from the map information having road information, building arrangement information, and the three-dimensional model. A three-dimensional landscape generation means for generating a three-dimensional landscape for the landmark building and the landscape building, and an image display means for displaying the three-dimensional landscapeThe building selection means includes means for selecting the landmark building candidate and the landscape building candidate, and setting priority for the three-dimensional landscape generation, and the city landscape generation means includes an image related to display. An image generation amount lower limit value is set within the range of the image generation amount upper limit value together with the generation amount upper limit value, and is displayed by the city landscape generation means based on the image generation amount upper limit value and the lower limit value when generating a three-dimensional landscape. Each time a screen is generated, a temporary upper limit value called a far limit value is calculated, and when displaying landmark buildings and landscape buildings within the range of the far limit value, the required image generation amount is set to the image generation amount upper limit value. If it does not exceed, select the landmark building candidate and the landscape building candidate within the range of the far limit value, and if the image generation amount upper limit value is exceeded, the priority order so as not to exceed the image generation amount upper limit value According to Based on said distal limit value, then means for selecting the landscape building as the mark buildings to be displayed on the screenIt is equipped with.
[0015]
The city landscape display device according to the present invention conforms to the distance from the viewpoint to the building or a distance index that is a numerical value equivalent thereto, a size index that is a building bottom area or a numerical value equivalent thereto, the height of the building or the number of floors of the building, etc. The building selecting means that uses at least one of the three height indices, which are numerical values, as a selection criterion for the landscape building is provided.
[0016]
The city landscape display device according to the present invention is at least one of the distance indicator, the size indicator, the height indicator, whether it is a landmark building, or a marker indicator indicating a degree of suitability as a landmark building. Is provided with the building selection means for using the mark as a selection criterion for the landmark building.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0021]
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a basic configuration diagram of a cityscape display device according to the first embodiment. In FIG. 1, reference numeral 10 denotes a building for storing building information including absolute coordinates (latitude, longitude, etc.) of each vertex and building height or floor information when the bottom shape of the building is approximated by a polygon (polygon). Information storage means, 20 is map information storage means for storing map information such as road position and building position, and 30 is city landscape generation means constituted by a computer that draws and generates a three-dimensional cityscape from building information and map information , 40 is an image display means for displaying the three-dimensional cityscape generated by the cityscape generation means 30. The three-dimensional landscape generation means 30 includes the following software, a building selection means 300, and a three-dimensional landscape drawing generation means 310. The 3D landscape drawing generation unit 310 includes a 3D model generation unit 311, a 3D landscape generation unit 312, and a drawing unit 313.
[0022]
The building information storage means 10 and the map information storage means 20 are composed of various storage devices and building information and map information stored therein. Examples of the various storage devices include a hard disk device, a CD-ROM device, a floppy disk device, or silicon (disk) (including smart media, memory stick, flash memory card, and the like). Although the building information storage unit 10 and the map information storage unit 20 are described as independent in FIG. 1, they are not necessarily independent devices. The areas may be divided and stored in the same storage device.
[0023]
Although not explicitly shown in FIG. 1, the cityscape generation means 30 has a CPU (Central Processing Unit) and a work area (memory), and has a building information storage means 10, a map information storage means 20, an image display means 40, and the like. Exchange data between them, including time management, set and support operating environment in 3D model generation means 311, 3D landscape generation means 312 and drawing means 313 included in 3D landscape drawing generation means 310 It has a function. For example, the three-dimensional model generation unit 311, the three-dimensional landscape generation unit 312, and the drawing unit 313 are usually configured by software, but a CPU (central processing unit), work area ( Memory) and management of a series of processes are performed in the cityscape drawing generation means 30. Furthermore, input means such as a cursor, a mouse, a joystick, and a cross button may be provided so that the user can input as necessary.
The image display means 40 can be composed of a graphic processor and a liquid crystal display or a video card with a three-dimensional high-speed display function and a CRT display.
[0024]
In FIG. 1, a thick line connecting the building information storage unit 10, the map information storage unit 20, the image display unit 40, and the city landscape drawing generation unit 30 indicates the connection relationship between the respective components, and the city landscape drawing A thin line in the generation unit 30 indicates a flow of information or a flow of processing.
[0025]
Here, an example of building information and map information stored in the building information storage means 10 and the map information storage means 20 will be supplemented. As described above, the map information includes positional information such as roads and buildings for each area, and serial numbers are assigned to the buildings included in each area. The building information is created by giving building information to this serial number for each area. As described above, specific building information is given in the form of the bottom shape (for example, the bottom is represented by polygons and given coordinate values for each vertex) and height (the number of floors and the height per floor). The building attributes (office buildings, condominiums, single-family houses, etc.) and landmark indicators described later can also be included as building attributes. In some cases, the building location information is included in the building information, and the map information may include only the serial number of the building included therein. Further, the shape of the park may be included in the map information or may be included as building information in a broad sense. Furthermore, as described above, the map information and the building information may be stored in the same storage means, but both information may be created and stored as a unit.
In the following, it is assumed that map information and building information are stored separately, and the position information of the building corresponds to the map information, and the building information corresponds to the building position included in the map information. It is assumed that attribute information is included.
[0026]
The feature of the first embodiment is that the building selection means 300 is introduced so that the landmark building and the landscape building can be automatically selected, and the building display area on the screen is divided into a plurality of areas. The building is displayed in a wider display area than the landscape building.
[0027]
Prior to describing the operation of the city landscape display device shown in FIG. 1, the display area classification at the time of image display on the image display means 40 and the selection of buildings related to the display on the building selection means 300 will be described.
[0028]
○ Display area classification
As described in the section of the related art, regarding the display method of the building, the display area is changed from the short distance to the non-display area, the semi-transparent display area, the opaque display area, the non-distant display area in order from the viewpoint. The opaque display area is divided into an opaque required display area and an opaque selection display area in order from the closest according to the distance from the viewpoint. As for the distance (= distance index) used as an index for region classification, a distance in the sense of the Euclidean space from the viewpoint, which is generally used as “distance”, may be used. 1-z, which is often used in the computer graphics field, may be used.
[0029]
Here, z is one of the coordinate axes of the three-dimensional coordinate system. When the right hand system is used, the right thumb is the x axis, the index finger is the y axis, the middle finger is the z axis, and usually the ground is y = 0. On the plane, the sky direction is the positive value of y. In this case, the line-of-sight direction is taken as the z-axis, the direction perpendicular to the z-axis and the direction perpendicular to the y-axis is taken as the x-axis, and the real coordinates are transformed, and the viewpoint coordinates are x = 0, y = 0, z = 1. It is said. In this case, the “numerical value according to distance” 1−z is a distance from the surface passing through the viewpoint and having the line-of-sight direction vector as a normal vector to the object (coordinates = x, y, z).
[0030]
The building display in each display area is as described in the section of the prior art. However, the opaque essential display area is an area for displaying both a landmark building and a landscape building, and an opaque selection display area is described below. It is defined as an area that displays only the landmark building. As a boundary value (distance from the viewpoint or a value corresponding thereto) that divides these areas, a fixed value may be assigned, or some function value may be used. An example of the latter is a setting method in which when the reduction ratio for display is changed, the boundary value between display areas is also changed in inverse proportion to the reduction ratio. Note that which display area each building is included in can be determined by reading the position of each building from map information or building information.
[0031]
Note that a building may extend over a plurality of display areas. In that case, a criterion for determining which display area a building belongs to may be determined by, for example, which display area a representative point of a building belongs to. The representative point of the building may be the point closest to the viewpoint or the center of gravity of the polygon among the vertexes of the polygon that approximates the bottom of the building. This representative point may be calculated each time, but may be stored in advance as building information.
[0032]
○ Selection of buildings for display
The building selection means 300 selects the landmark building and the landscape building as follows from the building group included in the map.
[0033]
◇ Scenery building
A building suitable for landscape expression, where the building index A satisfies the standard A as a landscape building candidate, and is classified by the distance from the viewpoint (or a value corresponding to this): Among a plurality of display areas, it is considered to be appropriate for the landscape, and is defined as being displayed in a predesignated area.
[0034]
As the designated display area based on the distance index, for example, a semi-transparent display area and an opaque required display area are used. The opaque selection display area is relatively distant from the viewpoint, is not important for the landscape, and this area is displayed in a relatively reduced form, so it is rather complicated to display a large number of buildings. Therefore, we decided to exclude it from the display target area of the landscape building.
[0035]
As an example of the index A related to the reference A, there is a method of using a bottom area or a value corresponding to it from the bottom shape included in the building information as a building size index and using it. When the bottom area is the index A, the reference A is a building whose bottom area is greater than a certain value, for example, the bottom area is larger than 200 square meters.
[0036]
The reason why the lower limit is set in the size index of the building related to the display is that if even a small building is displayed, the display screen becomes complicated depending on the district, which makes it difficult to understand the landscape. Of course, by setting the lower limit value to 0 square meters, it is possible to display virtually all buildings without setting the lower limit value, and the lower limit value can be changed according to the display reduction ratio. It is also possible to make it easy to see according to the reduction rate of the.
[0037]
Further, when the size index is the index A, the length of the maximum side of the building bottom may be used. Although the building has a width, it is small in thickness and is not so large in the bottom area, but it is also conspicuous on the landscape and can be taken as a landscape building because it is conspicuous. Naturally, it is also possible to select a landscape building by using both the base of the bottom area and the maximum side length of the bottom of the building as a size index.
[0038]
The above is an example of selecting a landscape building using a size index and a distance index, but in addition to this, the height index, size index, and distance index may be used to make a comprehensive selection. . Thus, when selecting a landscape building, by adding a height index together with a size index and a distance index, various types of landscape buildings can be selected, and the landscape can be expressed better.
[0039]
◇ Mark building
The distance from the viewpoint (or a value corresponding to this) from among the landmark building candidates that are suitable as landmarks and whose building index B satisfies the criterion B set to be more prominent than the criterion A Among the plurality of display areas divided by the above, the display area is not smaller than the display area of the landscape building, is considered appropriate for displaying the landmark building, and is defined as being displayed in the area designated in advance.
[0040]
The designated display area is, for example, a translucent display area, an opaque required display area, or an opaque selection display area. Compared to the example of the landscape building, the building selection area is expanded by the opaque selection display area. In order to make it a landmark, it is based on the judgment that it is necessary to display an area wider than the landscape building.
[0041]
As an example of the index B related to the reference B, there is a height or a floor number (height index) of a building. In this case, the reference B is a building whose height index is a certain value or more, for example, a building having 15 floors or more. It is based on the idea that tall buildings are suitable as landmarks. Moreover, the bottom area of a building or a value (size index) according to it can be significantly larger than that of a landscape building. For example, it has a bottom area of 1000 square meters or more, or the length of one side of the bottom surface exceeds 50 m.
[0042]
Also, the building information may have a mark or a degree of appropriateness as a mark in the building information as a mark index (for example, treated as a kind of attribute information). If the user thinks that it is very famous and has a distinctive appearance and is suitable as a landmark building, this landmark index may be added depending on the subjectivity. In other words, the landmark index can be determined and determined by humans comprehensively in consideration of social factors such as the famousness of the building. The indexing of the degree of appropriateness as a landmark can be realized by giving this as a numerical value. The selection of values depends on human subjectivity.
[0043]
If such a method is adopted, things that are not selected as landmark buildings from the height index and size index, such as the Imperial Palace and the National Diet Building, are suitable for landmarks due to factors such as name recognition and unique design, It is possible to set a landmark index by adding a landmark to the building information or by increasing the degree of the landmark.
[0044]
The scenery building and the landmark building are selected by a computer. However, by setting a landmark index in advance, the building is selected as a landmark building by human judgment.
[0045]
Furthermore, a height index, a size index, a landmark index, and a distance index may be added, and any combination of these may be selected and used as index B. For example, if an index B is obtained by multiplying the number of floors by the bottom area, it has a value close to the total floor area of the building and is excellent as an index indicating the size of the building. When this value is a certain value or more and the building in the specified display area is selected as a landmark building, it is selected by combining a combination of three types of information: height index, size index, and distance index. If a mark index is added to this, it is selected by combining four pieces of information in a composite manner.
[0046]
In some cases, a part of the landscape building overlaps with the landmark building. In this case, it is efficient not to select duplicates, and in practice, no overlap occurs, but the duplicate removal process is not essential.
[0047]
FIG. 2 is a flowchart for explaining the operation of the cityscape display device shown in FIG. Hereinafter, according to FIG. 2, operation | movement of the cityscape display apparatus shown in FIG. 1 is demonstrated.
Step 1 to Step 11 are processes in the city landscape generation means 30.
In Step 1 of FIG. 2, the viewpoint position and the line-of-sight direction are determined and it is determined which point on the map is the center of display. For example, in a car navigation system, a GPS (Global Positioning System) is used to calculate the viewpoint position and line-of-sight direction using a method such as grasping the current position and traveling direction of a car, so that any point on the map Decide whether to display in the center. Note that the user may select the viewpoint position and the line-of-sight direction by using an input device such as a cursor, a mouse, a joystick, or a cross button. In Step 2, the range on the map displayed on the image display means 40 is determined from this display center point, its viewing direction, and the specified scale factor. Note that the above-described display area divisions (proximity non-display area, translucent display area, opaque required display area, opaque selection display area, and remote non-display area) are also performed here.
[0048]
In Step 3, a map in a range to be displayed by the image display unit 40 is selected from the map information stored in the map information storage unit 20 and read into the city landscape generation unit 30. In Step 4, the buildings included in each display area determined in Step 3 are extracted, and the building information is read from the building information storage means 10.
[0049]
In Step 5, a distance index, a height index, a size index, and a landmark index are extracted and calculated from the building position, height, bottom shape, and landmark index included in the building information. Select m landmark buildings and n landscape buildings. The selection criteria are as described above. Here, for example, a building having a bottom area of 200 square meters or more in a semi-transparent display area and an opaque essential display area is a landscape building, and a semi-transparent display area, an opaque essential display area, and an opaque A building having a height of 15 floors or more in the selection display area is a landmark building.
[0050]
In Step 6, using the building information such as the bottom shape and height (or the number of floors) of the building, the 3D model generation means 311 generates a 3D model of the building i (= 3D model i). . A three-dimensional model of a building is a three-dimensional model of a building. For example, a polygonal column whose bottom is a bottom polygon included in building information and whose height is the height of the building is an example of a three-dimensional model of a building. It is. The three-dimensional model i is generated as opaque and translucent for each display area.
[0051]
In Step 7, the 3D landscape generation means 312 is used to place the 3D model i generated in Step 5 on the map of the display target range determined in Step 3 to generate the 3D landscape i. In Step 8, the drawing means 313 generates a projection map i that is a two-dimensional projection map of the three-dimensional landscape i from the viewpoint. In Step 9, the projection map i generated in Step 8 and the projection map of the three-dimensional landscape i-1 generated in the previous process are added, and hidden surface processing is performed to obtain the projection map of the three-dimensional landscape i.
[0052]
In Step 10, it is determined whether or not to finish, and it is determined whether m landmark buildings and n landscape buildings have all been processed in the respective display areas. If the processing is completed, the process proceeds to Step 12, and the processing is completed. If not, move to Step11. In Step 11, move the target building to the next building and return to Step 6. In Step 12, the projected view of the three-dimensional landscape i obtained in Step 8 is displayed on the image display means 40 for each landmark building and landscape building.
[0053]
As a result of the above, finally, the projected images of the landmark building and the landscape building are divided into the semi-transparent display and the opaque display for each display area on the map, and the image display means 40 is arranged at a predetermined position. Is displayed.
[0054]
FIG. 3 shows an example in which the projection diagram of the three-dimensional landscape generated in this way is displayed as an image. In FIG. 3, reference numeral 400 denotes a frame of the display screen of the display means 40. In a multi-window system instead of full screen, this is the window boundary. 410 is a horizontal line, 420 is a distant non-display area, 430 is an opaque selection display area, 440 is an opaque required display area, 450 is a semi-transparent display area, and 460 is a proximity non-display area. 401 is a landscape building that is translucently displayed because it is in a translucent display region, 402 is a landscape building that is opaque because it is in an opaque required display region, and 403 is a landmark building that is built in an opaque display region. is there.
[0055]
In this example, a building having a bottom area of 200 square meters or more in a semi-transparent display area or an opaque required display area is displayed as a landscape building, and the number of floors is 15 in the semi-transparent display area, the opaque required display area, and the opaque selection display area. Buildings above the floor will be displayed as landmark buildings. Since buildings that are prominent in terms of size and height in the semi-transparent display area and the opaque display area are displayed, the scenery and atmosphere of the target area are displayed realistically. In the slightly distant opaque selection display area, a building of 15 floors or more as a landmark is displayed, but a low-rise landscape building is not displayed. This is because even if a low-rise building in the distance is displayed, it is hidden by the building in front and it has no meaning, or it becomes unnecessarily miscellaneous, making it difficult for the user to recognize and identify. is there.
[0056]
According to the present embodiment, as described above, the function of the landmark and the landscape can be set independently for the display of the cityscape, so that the landmark building can be surely displayed and the landscape building can be appropriately displayed. By selecting, by improving the reality of the entire landscape and combining this with the selection of the display area, it is possible to display the landmark building easily. Furthermore, since the number of buildings related to display can be effectively reduced, the burden on the image generation processing capability of the device can be reduced, and even if the image generation processing capability of the device is limited, the real-time display performance can be improved. Smooth display can be realized.
[0057]
Embodiment 2. FIG.
In the second embodiment, the building selection means 300 is added with a function of selecting a landmark building candidate and a landscape building candidate and setting a priority order for generating a city landscape. The necessity of the priority order comes from the restriction of the image generation processing capability of the apparatus.
[0058]
For example, taking a car navigation system as an example, consider display while moving. Assume that the image generation and display capability of the apparatus is an effective performance of 100,000 polygons (polygons) per second. If the viewpoint moves with the movement, the screen scrolls. Therefore, in order to realize a smooth image display with the scrolling, a certain number of frames (screens) must be displayed every second. Now, let this required number of frames be 30 frames per second. (At least 12 frames per second are required. If there is a display of 30 frames per second, it looks smooth. At 60 frames per second or more, the human eye cannot distinguish the difference.) The above effective performance is set as the upper limit of the image generation amount of the apparatus. Then, in this case, drawing of 3300 polygons per frame becomes the image generation amount upper limit value. This value is called the upper limit polygon number.
[0059]
In this way, the upper limit of the image generation amount that can be drawn (hereinafter referred to as the upper limit number of polygons) is determined due to the restrictions on the image generation processing capability of the apparatus. Therefore, when all the landscape buildings and landmark buildings are drawn. If there is a possibility that the required number of polygons may exceed this maximum number of polygons, in order to obtain a smooth display, it is necessary to prioritize the buildings and exclude the buildings with lower priority from being drawn. .
[0060]
The second embodiment is an embodiment of the invention made to cope with the situation where the image generation processing capability of the apparatus is thus limited.
[0061]
The processing procedure of the second embodiment will be described with reference to the flowcharts of FIGS.
The contents of Step 1 to Step 4 in FIG. 2 are the same as those in the first embodiment.
For Step 5, the building selection means 300 does not select a landscape building or landmark building, but selects a landmark building candidate and a landscape building candidate, and prioritizes them in the form of priority number i (details) Will be described later.)
[0062]
Step 6 is the same as that of the first embodiment, but before moving to Step 7, Steps 6.1 to 6.4 shown in FIG. 4 are inserted. In Step 6.1, the required number of polygons (abbreviated as the number of polygons in building i) when projecting and drawing the three-dimensional model i of the building i generated in Step 6 is estimated. (Details will be described later.)
In Step 6.2, the total number of polygons from building 1 to building i-1 is added up, and the total number of polygons i-1 estimated in Step 6.1 is added to obtain the total number of polygons i. .
[0063]
In Step 6.3, it is determined whether the accumulated polygon number i exceeds the upper limit polygon number. If it exceeds the limit, the upper limit of the image generation processing capacity has been reached, so the processing after building i is stopped, and the procedure goes to Step 12 via Step 6.4, the procedure for displaying up to building i-1. . If it does not exceed, the upper limit of the image generation processing capability constraint has not yet been reached, and the process proceeds to Step 7. Step 7 to Step 12 are the same as those in the first embodiment.
[0064]
How to prioritize landscape building candidates is a method of increasing the priority according to the size of the bottom area in each display area (method based on the size index value), and a method of increasing the priority as the viewpoint is closer ( A method based on the value of a distance index (excluding the proximity non-display area), etc.), at least one of which is an index, and the priority order can be determined according to the index value. In each display area, there is a method of increasing the priority according to the magnitude of the value obtained by multiplying the bottom area and the height for each display area (a method combining a distance index, a size index, and a height index).
[0065]
In addition, in the case of a landmark building candidate, a landmark index is added to the height index, size index, and distance index, and at least one of these indices can be used as an index, and a priority order can be determined according to the index value. It is possible to determine the priority order by combining them, but it is necessary to set the selection criteria so that they stand out more than the landscape building candidate and determine the priority order, regardless of which method is used. In addition, when assigning priorities, it is necessary to digitize the mark index in the form of the degree of appropriateness as a mark.
[0066]
The priority order of the landmark building candidate and the landscape building candidate is set independently, and the priority order of the landmark building candidate is usually higher than the priority order of the landscape building candidate. The order may be mixed. As a method of mixing priorities, a method of converting both priorities into one priority with a fixed relational expression may be used. For example, the priority number of the landscape building candidate is a number multiplied by M, and the priority number of the landmark building candidate is used as it is. Increasing M increases the priority of the landmark building candidate. By such a method, it is possible to allow the landmark building candidate to be mixed with the priority order of the landscape building candidate while increasing the priority of the landmark building candidate.
[0067]
The estimation of the number of polygons necessary for drawing the projection of the three-dimensional model i of the building i may be calculated strictly or not necessarily. In any case, it is important to shorten the calculation time. As an approximate method, since the probability of seeing the wall surface is approximately 1/2, if the number of vertices of the bottom polygon of a building is w, the number of side walls is w, which is approximately w / 2. It may be approximated that the surface is visible. In the bird's-eye view, the ceiling surface can be seen, and 1 + w / 2, which is 1 added to this, can be estimated as the number of polygons required for the approximate drawing of the building.
[0068]
On the other hand, as a slightly strict calculation method, for example, consider a coordinate system in which the ground is a plane with y = 0. The side wall surface with the base side EF of the building's bottom polygon (however, points E (x1, 0, z1), F (x2, 0, z2)) are perpendicular to the ground. When the vertex is clockwise when viewed from the sky, the normal vector can be expressed as (a, 0, b). However, a = z2−z1 and b = x1−x2. A plane passing through the point (x1, 0, z1) and having the normal vector as (a, 0, b) is a · (x−x1) + b · (z−z1) = 0. The plane can be seen only from the region of a · (x−x1) + b · (z−z1)> 0. Therefore, if the viewpoint is (u, v, w), this plane may be visible only from the region of a · (u−x1) + b · (w−z1)> 0, otherwise it will never be seen. . In this case, each side wall surface can be determined by performing multiplication twice and slight addition / subtraction. To determine whether or not the ceiling polygon is visible, the viewpoint and the height of the ceiling may be compared. If the viewpoint is higher, you can see it, and vice versa. Also, the bottom polygon is never visible. With this calculation, the total number of polygons can be calculated fairly precisely.
[0069]
The priority setting is a landmark building candidate → a landscape building candidate, and for each candidate for a landmark building and a landscape building, for example, when increasing the priority of a thing with a small distance from the viewpoint, for example, in a landscape building candidate, Even if the upper limit number of polygons is exceeded in a building with an opaque required display area, all landmark buildings are displayed, and the scenery building candidate is already displayed in a part closer to the viewpoint. If the number of buildings increases in urban areas, there may be more landscape building candidates that are not related to display, and in some cases, some of the landmark building candidates may not be displayed, but they are displayed Speaking of the relationship with buildings, they have to be allowed because they have a low display priority.
[0070]
Note that the upper limit polygon number is considered a little more flexibly. For example, there is a method in which all landmark building candidates are displayed even if the number of frames that can be displayed per second is sacrificed to some extent. In this case, it is determined whether or not the number of landmark building candidates, m, has been reached between Step 6 and Step 6.1 in FIG. 4, and if not reached, the process proceeds to Step 7, and if reached, Step 6.1 is reached. You can add a process to move to. Although there may be some dissatisfaction in terms of smooth display when scrolling, all landmark building candidates are displayed as landmark buildings.
[0071]
According to the present embodiment, the image generation processing capability of the apparatus is limited, and even when the screen is scrolled, the display of the image generation processing capability is full while maintaining a smooth display without causing a human eye to feel a time delay. Can be used to display as many landmarks as possible in the range and buildings that express the landscape. Therefore, even when the screen is scrolled in the presence of a large number of buildings, the smooth display, the landmark function, and the landscape expression function can be well balanced.
[0072]
Embodiment 3 FIG.
This embodiment is for displaying with little flicker when scrolling the screen.
An overview of the display screen when scrolling is as follows.
Scrolling moves the viewpoint, but as the viewpoint moves, the boundary line of each display area also moves, and the landmark building and landscape building included in it change. Go. For example, if the landmark building or landscape building that belonged to the translucent display area moves forward, it moves to the proximity non-display area and disappears from the display screen. Since it passes through the proximity non-display area from the semi-transparent display area, it disappears from the opaque display to the semi-transparent display and then disappears from the display screen. Since the landmark building in the opaque selection display area moves to the proximity non-display area through the opaque required display area and the semi-transparent display area, the opaque display continues for a while and then becomes semi-transparent and disappears from the display screen. Scenery building candidates in the opaque selection display area are not initially displayed, but disappear from the screen through opaque display and translucent display as they move from the opaque required display area to the semi-transparent display area and the proximity non-display area. .
[0073]
In this way, both the landmark building and the landscape building follow the process of appearance, opaque display, translucent display, and disappearance with scrolling, but such changes in display are in accordance with one pattern, It can be recognized as a natural flow for what you are seeing, and it does not give you a strange feeling.
[0074]
However, if a building or landscape building that was intended to be used as a landmark disappears unexpectedly or appears, it will be confusing, and if the display / non-display of the building is frequently switched (so-called flickering of the screen), the user is frustrated. Make it go.
[0075]
In the second embodiment, the priority order is set for the landmark building candidate and the landscape building candidate, so that the display of necessary buildings is ensured while the image generation processing capability of the device is limited. For this reason, when scrolling the screen, there may be a flicker phenomenon in which display / non-display of a specific building is frequently switched.
[0076]
For example, it is assumed that the number of landmark buildings has increased or decreased significantly. In such a case, the priority order of the building frequently changes, and the display / non-display of the priority order building near the display limit is frequently switched. When there are many landmark buildings, there is a possibility that some of the landmark buildings frequently switch such display / non-display, but in general, they are likely to occur in landscape buildings.
[0077]
In the third embodiment, in addition to the upper limit polygon number introduced in the second embodiment, the lower limit polygon number and the far limit value are introduced, and FIG. 2 additionally corrected in the second embodiment (partial correction of Step 5) Step 6.1 to 6.4)) is replaced with Step 6.1 to 6.7 shown in FIG. 5 to reduce the display flicker in the above sense. It is to provide.
[0078]
The lower limit polygon number is set smaller than the upper limit polygon number, for example, a value corresponding to 80% of the upper limit polygon number. As will be described later, the lower limit polygon count is also one of the constraints on the total number of polygons related to display. If this lower limit polygon count is set too small, the number of displayed buildings will be reduced, and the upper limit polygon count will be reduced. If it is too close, the effect of reducing flicker reduction that switching between display / non-display of a building frequently occurs is reduced. Therefore, it is a numerical value that should determine an appropriate value from the balance of both effects.
[0079]
The third embodiment is modified as shown in FIG. 2 (however, it is assumed that the processing is prioritized in Step 5 and Steps 6.1 to 6.7 are added in Step 5), and Steps 6.1 to 6.7 are added. FIG. 5 is a flowchart showing the above.
[0080]
The contents of Steps 1 to 6 and Steps 7 to 12 in FIG. 2 are the same as those in the second embodiment. The building priority setting in Step 5 is for the landmark building candidate and the landscape building candidate. In this case, the priority of the building that is close to the viewpoint is increased (however, the hidden area is excluded), and the landmark building candidate. Shall have a higher priority than landscape building candidates.
Steps 6.1 to 6.7 shown in FIG. 5 are inserted between Step 6 and Step 7. Hereinafter, Steps 6.1 to 6.7 will be described with reference to FIG.
[0081]
Step 6.1 and Step 6.2 in FIG. 5 are the same as those in FIG. 4 according to the second embodiment. That is, the accumulated polygon number i is calculated so far.
In Step 6.3, the accumulated polygon number i is compared with the upper limit polygon number. If the accumulated polygon number i exceeds the upper limit polygon number, the process proceeds to Step 6.6. If not, the process proceeds to Step 6.4.
[0082]
In Step 6.4, the distance from the viewpoint of the target building i is the far limit value already set (the initial value if it is the first screen, otherwise Step 6.6 If it is smaller than the far limit value set in step), go to Step 7. Otherwise, go to Step 6.5.
[0083]
In Step 6.5, if the accumulated polygon number i is equal to or greater than the lower limit polygon number, the process proceeds to Step 6.6, and if not, the process proceeds to Step 7.
In Step 6.6, the distance from the viewpoint of the building i when the accumulated polygon number i exceeds the upper limit polygon number or when the accumulated polygon number i exceeds the lower limit polygon number is set as the far limit value. Here, the initial value of the far limit value may be an arbitrary value.
[0084]
The operation of the apparatus according to the above procedure will be described with a specific example according to FIG.
In FIG. 6, the horizontal axis represents the far limit value (or distance from the viewpoint), and the vertical axis represents the number of buildings or the total number of polygons. The straight line A and the straight line B indicate how the number of buildings to be displayed changes with the distance from the viewpoint for a certain area A and B, respectively. Since the number of buildings on the vertical axis is equivalent to the number of accumulated polygons necessary to display it, the vertical axis will be treated as the number of accumulated polygons hereinafter. The straight line A and the straight line B are monotonically increasing functions, but are assumed to be straight lines for simplicity of explanation here. Further, in FIG. 6, a horizontal line is drawn with a chain line at the vertical axis position corresponding to the upper limit polygon number and the lower limit polygon number. The distances (or far limit values) of the intersections of the alternate long and short dash lines and the straight lines A and B indicating the upper limit polygon number and lower limit polygon number are A1, A2, B1, and B2, as shown in the figure. Furthermore, it is assumed that the initial value of the far limit value is A0, and A0 is a value between A1 and A2 as shown in FIG.
[0085]
Considering a car navigation system, it is assumed that the vehicle is moving from time Ta to Tb, and that the region A is reached at time Ta and the region B is reached at time Tb. In this case, since the total number of polygons at the distance A0 is between the upper limit polygon number and the lower limit polygon number from the straight line A, the processing of the building for display at the time Ta is the first constraint condition in Step 6.4 of FIG. It becomes. That is, when the processing of the building within the distance range equal to the far limit initial value A0 is finished and the processing of the building exceeding the distance A0 is attempted, the process proceeds to Step 6.5 in FIG. In Step 6.5, since the total number of polygons at the distance A0 exceeds the lower limit polygon number, the process moves to Step 6.6, the far limit value is set to A0, and the buildings within the range up to the distance A0 are Displayed as screen A.
[0086]
Next, when the time Tb elapses, the dependency of the distance / polygon number becomes the dependency of the distance / polygon number as shown by the straight line B in FIG. That is, the number of buildings is increasing. Since the total number of polygons for the distance A0 of the straight line B exceeds the upper limit number of polygons from FIG. 6, the upper limit number of polygons in Step 6.3 in FIG. 5 is the first constraint condition this time. In other words, in Step 6.3, the total number of polygons is greater than or equal to the maximum number of polygons at a distance B1 that is smaller than the far limit value A0. , Displayed as screen B.
[0087]
Next, when the time Tc elapses and the region C is reached, the relationship between the number of polygons and the distance is the same as that of the straight line A, for example. (This is not necessarily the same, but it is a measure for simplifying the explanation.) At this time, since the number of accumulated polygons at the distance B1 is smaller than the lower limit polygon number from the straight line A, Step 6.5 in FIG. The lower limit polygon number is the first constraint condition. That is, the number of processing buildings is increased to a distance where the total number of polygons becomes equal to the lower limit number of polygons. When the total number of polygons becomes equal to or greater than the lower limit number of polygons, the building processing ends, and the process proceeds to Step 6.6. The far limit value is set to A2, and the buildings within the range up to the distance A2 are displayed as the screen C.
[0088]
In the case of controlling display / non-display switching only by the restriction condition of the upper limit number of polygons of the second embodiment, when the case of FIG. 6 is applied, as time elapses from Ta → Tb → Tc, The far limit value changes greatly from A0 → B1 → A1, but according to the third embodiment, the far limit value changes from A0 → B1 → A2 to a small extent.
Therefore, as the change is suppressed, the number of buildings related to display / non-display switching decreases, and the flicker phenomenon is alleviated.
[0089]
Hereinafter, this point will be seen in more detail with reference to FIGS.
Here again, a case is assumed in which the screen is scrolled as the vehicle moves, as in a car navigation system.
[0090]
FIG. 7 shows the distance limit value corresponding to the upper limit value and the distance limit corresponding to the lower limit value as the distance range in which the horizontal axis indicates the time and the vertical axis indicates the far limit value and the total number of polygons is equal to the upper limit polygon number and the lower limit polygon number. The value is defined and its change over time is shown by a solid line. A large distant limit value means that the number of buildings is small. FIG. 8 shows changes in the number of buildings (or the number of accumulated polygons) with distances at times T1 to T12 shown in FIG. Here, for the sake of simplification, this change is assumed to be a straight line, and each time T1 to T12 is described as a parameter at the right end of the straight line. When the straight line at each time is the same, each time is indicated as T10 / T11 / T12 or the like at the right end of each corresponding straight line. Each straight line coincides with the upper limit corresponding far limit value and the lower limit corresponding far limit value at each time of FIG.
[0091]
Next, the initial value of the far limit value (which may be an arbitrary value) is, for example, V0. According to FIG. 8, the total number of polygons at the distance V0 of the straight line T1 is located between the upper limit polygon number and the lower limit polygon number. Therefore, Step 6.4 in FIG. 5 is the first constraint condition, and the building processing up to the distance V0 is performed according to FIG. At this time, the judgment in Step 6.5 is Yes from FIG. 8, and the process proceeds to Step 6.6. Since the distance at this time is V0, the far limit value set there remains V0, and far away It does not change from the limit value.
[0092]
At time T2, the far limit value set at time T0 is V0, and the far limit value set at time T0 is between the upper limit corresponding far limit value and the lower limit corresponding far limit value at time T2. Therefore, for the same reason as at time T1, the far limit value set value at time T2 remains unchanged at V0.
[0093]
Similarly, the far limit value set value does not change at times T3 and T4 and remains V0. That is, if the far limit value at the previous time is located between the upper limit corresponding far limit value and the lower limit corresponding far limit value at the new time, the newly set far limit value is the previous value. It remains unchanged.
[0094]
Next, consider the time from time T4 to T5. From the straight line T5 in FIG. 8, the cumulative polygon number at the distance V0 is smaller than the lower limit polygon number. Accordingly, in this case, Step 6.5 in FIG. 5 is the first constraint condition, and the range (= distance) of the processing target building is increased until the cumulative polygon count exceeds the lower limit polygon count. When the cumulative polygon number becomes equal to or greater than the lower limit polygon number, the processing ends. At this time, the far limit value is a far limit value determined by the lower limit polygon number, that is, the far limit value V1 corresponding to the lower limit value at time T5 in FIG. Set to
[0095]
At time T6 that follows, the situation is the same as at time T5, and both the upper limit corresponding far limit value and the lower limit corresponding far limit value are larger than the far limit value V1 set at time T5. Accordingly, the far limit value newly set at time T6 is equal to the lower limit corresponding far limit value V2 at time T6. Between time T7 and time T9, the far limit location setting value at the previous time is located between the upper limit corresponding far limit value and the lower limit corresponding far limit value, so the far limit value remains unchanged and remains V2. It is.
[0096]
Next, consider the time from time T9 to time T10. In this case, it can be seen from the straight line T10 in FIG. 8 that the upper limit number of polygons is exceeded at a distance V3 that is much smaller than the distance V2. Therefore, Step 6.3 in FIG. 5 becomes the first constraint condition, and the distance V3 of the building where the total number of polygons exceeds the upper limit number of polygons is set as the far limit value. At times T11 and T12, since the set far limit value is equal to the upper limit corresponding far limit value, the far limit value remains unchanged.
[0097]
The far limit value thus set is indicated by a broken line and a circle in FIG.
The phenomenon of frequent switching (so-called flickering) of the display / non-display of a specific building that occurs when there is a sudden increase or decrease in the number of buildings when scrolling the screen while the image generation processing capacity of the device is limited 7 is caused by a sudden change of the far limit value corresponding to the upper limit value, but according to the present embodiment, the sudden change of the far limit value is mitigated as shown in the time change of the set far limit value of FIG. Has been. Therefore, the flicker phenomenon is alleviated, and smooth display with little flicker can be realized even when the screen is scrolled.
[0098]
Embodiment 4 FIG.
In the cityscape display, the reality improves as the number of displayed buildings approaches the actual number of buildings, but it is not always better to display many buildings in terms of visibility. If the number of buildings to be displayed is too large, a complicated impression is given, and the display screen becomes difficult to see. This embodiment is devised not to give a complicated impression while displaying necessary buildings. The maximum number p of buildings to be displayed is introduced as a complexity indicator, and the total number of displayed buildings is limited to this value. It is what you do.
[0099]
This embodiment will be described with reference to the flowchart of FIG.
In FIG. 2, Step 1 to Step 7 are the same as those in the first embodiment. The condition for determining whether to end Step 10 is not the total number of buildings m + n shown in the first embodiment, but the maximum number of buildings p. However, if this value is larger than m + n, it is replaced with m + n. In addition, although Embodiment 1 demonstrated as a landmark building and a landscape building here, since the priority order concerning the display of a building is decided beforehand and not all are displayed, below, it is a display object. Until it is decided, it will be called landmark building candidate, landscape building candidate, and in Step 5, each priority has already been decided, and the normal landmark building candidate priority is higher than the priority of landscape building candidate, In that case, among the landscape building candidates n, pm is the number of landscape buildings related to the display. If p−m is greater than n, all landscape buildings are displayed.
[0100]
The maximum display building number p may be a fixed value or may be given as a function value.
In addition, the user may select each time. However, if the value is a fixed value, the difference will not be displayed on the display screen, whether it is a large city or a small city, except for the difference in the size of individual buildings. Therefore, there is a problem in that it is a display of the cityscape. On the other hand, this can be improved when given as a function value. For example, the maximum number p of displayed buildings is 100 as a lower limit and 500 as an upper limit, and during that period, the number of display candidate buildings (total value of landmark building candidates and landscape building candidates) q is 70%.
In this way, when the number of candidate buildings becomes 100 or more, the number of display buildings changes in proportion to the number of display candidate buildings, and thus a display that reflects the cityscape to some extent is possible. The upper limit is set for the maximum number of displayed buildings because of restrictions on image generation processing capability, and is the same as the reason for setting the upper limit number of polygons described in the second or third embodiment.
[0101]
As an example of the user's selection each time, if there is a building that you want to use as a landmark among the landscape building candidates, but it is not displayed on the current display screen, this is displayed and the positional relationship from the current location When the user wants to confirm, there is a case where the maximum number of buildings to be displayed is temporarily increased (in some cases at the expense of smooth display) and the target building is displayed on the screen.
[0102]
As described above, according to the present embodiment, since the building display can be prevented from becoming more complicated than a certain limit, the display can be easily viewed. As a result, the number of buildings related to the display is reduced, so that the display can be improved smoothly when the screen is scrolled.
[0103]
【The invention's effect】
  The city landscape display device according to the present invention comprises a building selection means for selecting a landmark building that is a building suitable as a landmark and a landscape building that is a building necessary for better displaying the landscape, and the selected landmark A 3D model is generated for the building and the landscape building by using the building information, and the 3D landscape is selected for the selected landmark building and the landscape building from the map information having the road information, the layout information of the building, and the 3D model. 3D landscape generation means for generating the image and image display means for displaying the 3D landscapeThe building selection means includes means for selecting the landmark building candidate and the landscape building candidate, and setting priority for use in the three-dimensional landscape generation. Along with the image generation amount upper limit value, an image generation amount lower limit value is set within the range of the image generation amount upper limit value, and at the time of three-dimensional landscape generation, based on the image generation amount upper limit value and lower limit value, by the three-dimensional landscape generation means Each time the display screen is generated, a temporary upper limit value called a far limit value is calculated, and when displaying landmark buildings and landscape buildings within the range of the far limit value, the required image generation amount is the image generation amount upper limit value. If it does not exceed, the landmark building candidate and landscape building candidate within the range of the far limit value is selected, and when the image generation amount upper limit value is exceeded, the priority is set so that the image generation amount upper limit value is not exceeded. According to rank Occurs when there is a sudden increase or decrease in the number of buildings when scrolling the screen while there is a restriction on the image generation processing capacity of the device by providing means to select the landmark building and landscape building displayed on the screen Thus, it is possible to reduce the frequent switching (so-called flicker) phenomenon of display / non-display of a specific building. As a result, in addition to the real-time display, the flicker phenomenon can be improved and a smooth display can be achieved.
[0104]
The city landscape display device according to the present invention conforms to the distance from the viewpoint to the building or a distance index that is a numerical value equivalent thereto, a size index that is a building bottom area or a numerical value equivalent thereto, the height of the building or the number of floors of the building, etc. By providing the building selection means that uses at least one of the three height indices, which are numerical values, as the selection criteria for the landscape building, the degree of freedom in selecting the combination of the selection means for the landscape building or the selection means is increased. Since it becomes large, selection of an appropriate landscape building becomes easy to express the entire landscape well.
[0105]
In the cityscape display device according to the present invention, as a selection criterion for the landmark building, the distance indicator, the size indicator, the height indicator, whether it is a landmark building, or a landmark indicator indicating a degree of suitability as a landmark building By providing the building selection means that uses at least one of the four indicators, the degree of freedom in selecting the landmark building selection means or the combination of the selection means is increased, so that a more appropriate landmark building can be selected as a landmark. Becomes easier.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration diagram of a cityscape display device according to the present invention.
FIG. 2 is a flowchart of the first embodiment.
FIG. 3 is a display screen example according to the first embodiment.
4 is an additional correction corresponding to the second embodiment in the flowchart of FIG.
5 is an additional correction corresponding to the third embodiment in the flowchart of FIG.
[Fig. 6] Relationship between the far limit and the number of buildings (or the number of accumulated polygons)
[Fig. 7] Time change of far limit value and far limit set value corresponding to upper and lower limit values
[Fig. 8] Relationship between distance limit and number of buildings (or total number of polygons) at each time
[Explanation of symbols]
10 building information storage means, 20 map information storage means,
30 city landscape generation means, 40 image display means, 300 building selection means,
310 3D space drawing generation means, 311 3D model generation means,
312 drawing means, 313 three-dimensional space generation means, 400 display screen frame of display means 40, 401 landscape building made translucent display in semitransparent display area,
402 Landscape building displayed opaque in the opaque required display area, 403 Mark building displayed opaque in the opaque required display area and opaque selection display area,
410 horizontal line, 420 far non-display area, 430 opaque selection display area, 440 opaque required display area, 450 translucent display area, 460 proximity non-display area

Claims (3)

Building selection means for selecting a landmark building that is a suitable building as a landmark and a landscape building that is a building suitable for landscape expression using building information having bottom shape and height information of the building, the selected For the landmark building and the landscape building, the building information having the bottom shape and the height information is used to generate a three-dimensional model of the building, and the road information, the map information having the building arrangement information, and the three-dimensional model, A city landscape generation unit that generates a three-dimensional landscape for the selected landmark building and landscape building, and an image display unit that displays the three-dimensional landscape , the landmark selection unit and the landscape building candidate included in the building selection unit And a means for setting a priority for use in the three-dimensional landscape generation, and the image generation amount upper limit value for display in the city landscape generation means. An image generation amount lower limit value is set within the upper limit range, and at the time of generating a three-dimensional landscape, based on the image generation amount upper limit value and lower limit value, each time a display screen is generated by the city landscape generation means, a far limit value and When calculating the provisional upper limit value to be called and displaying the landmark building and the landscape building within the range of the far limit value, if the required image generation amount does not exceed the image generation amount upper limit value, If the landmark building candidate and the landscape building candidate within the range are selected and the image generation amount upper limit value is exceeded, the image generation amount upper limit value is not exceeded, based on the far limit value according to the priority order, the next A city landscape display device comprising means for selecting the landmark building and the landscape building displayed on the screen .   The distance index from the viewpoint to the building or a numerical value corresponding to it, the size index that is the numerical value corresponding to the building bottom area or the numerical value corresponding to it, the height index that is a numerical value corresponding to the height such as the height of the building or the number of floors of the building. The city landscape display device according to claim 1, further comprising the building selection unit that uses at least one of them as a selection criterion for the landscape building. Use at least one of the four indicators, the distance indicator, the size indicator, the height indicator, whether it is a landmark building, or a landmark indicator indicating the degree of suitability as a landmark building as a selection criterion for the landmark building The cityscape display device according to claim 2 , further comprising the building selection means.

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