KR101004350B1 - Fabricating method and apparatus for shaded relief map - Google Patents

Abstract

PURPOSE: A shadow relief map producing method and an apparatus thereof for having the sense of reality are provided to express the shadow relief map with the feeling of movement and the sense of reality. CONSTITUTION: A basic shadow source generating unit(22) originally receives a map from geographical information database. The basis shadow source generating unit generates the basic shadow source. A three-dimensional topography generating unit(23) generates three-dimensional topography. A screen shadow source generating unit(24) generates the screen shadow source by the basic shadow source. A shadow synthesis unit(25) synthesizes the screen shadow source in the three-dimensional topography.

Description

Method and apparatus for making shaded relief map {FABRICATING METHOD AND APPARATUS FOR SHADED RELIEF MAP}

The present invention relates to a method for producing a shadow relief and a shadow relief device, and more particularly, using a digitized two-dimensional geographic information provided from a geospatial database, the user can three-dimensionally perceive the shade as real terrain A method of manufacturing a relief degree and a device for manufacturing a shadow relief degree.

A geographic information database is a database that stores numerical maps that are produced by the country and released to each mapmaker.

Numerical diagrams (circularities) are those that measure the altitude of the actual terrain relative to sea level or geoid, and express the measured altitude as contours or arbitrary figures, and also include geographic information, geological information, and environmental information. Refers to a map with the same information.

The shaded relief map represents only a part of the information to be provided to the user among a large number of information such as contours or figures represented in the numerical diagram, and uses the shadow effect and / or color to express the relief of the terrain. Refers to a map that appears to be dimensional solid terrain.

As a conventional method of manufacturing a shaded relief, for example, as disclosed in Patent Registration No. 10-490670, the contours on the two-dimensional basic diagram as a circle is generated as a vector image according to a predetermined height and then generated for each height A shadow source generation step of generating a shadow source for representing a stereoscopic image by transforming information into vector data by matching adjacent upper and lower vector images among layers, and capturing geological maps, distribution maps, and terrain using mapping techniques. After preparing the source to be mapped to the 3D image by analyzing the data, the area is created by texture, and the mapping source generation step of filling the source at the corresponding location by displaying the distribution of each area such as rocks and trees on the map, and mapping with the shadow source Set the beam to be constantly projected at an arbitrary angle so that the source is displayed on the solid at a constant angle regardless of location or terrain. Information for correcting the positional mismatch of information generated when the two-dimensional information is converted into three-dimensional information by projecting two-dimensional information such as a ray setting step, previously investigated hiking information, road information, and location information And a map completion step of completing a mountain three-dimensional special map after correcting the positional inconsistency of the information.

However, the shadow relief produced by such a conventional method is, as shown in Fig. 11, the relief shape of the terrain represented in two dimensions, the illumination represented by the relief of the terrain (for example, solar lighting Shadows), colors applied according to the ups and downs of the terrain, etc., lack of liveliness and realism.

Accordingly, an object of the present invention is to provide a manufacturing method and apparatus capable of generating a more vibrant and realistic shaded relief degree.

In order to achieve the above object, the present invention provides a circle preparation method for preparing a circle in which two-dimensional contour lines represent a relief of any target terrain to generate a shaded relief map in which the height difference of the terrain is three-dimensionally expressed. step; Extracting the closed curves by the contours from the circle, giving the dark curve having the first black brightness to the closed curve by the contour of the lowest elevation, and the second brightness of white to the closed curve by the highest elevation Generating a basic shadow source having a light shade having a brightness having a brightness between the first brightness and the second brightness in the contour of the altitude between the lowest and the highest altitudes; ; A three-dimensional terrain generation step of generating a three-dimensional stereoscopic terrain having a higher altitude as a portion having the first brightness as a floor according to the brightness of each part of the basic shading source, and having a brightness closer to the second brightness; Generating a screen shadow source by inverting brightness of the basic shadow source; By synthesizing the generated stereoscopic terrain and the screen shading source, the higher brightness portion of the screen shading source transmits less of the contour of the stereoscopic terrain, and the lower brightness portion of the screen shading source sharpens the contour of the stereoscopic terrain. Screen shading source synthesis step of transmitting transparently; A method of producing a shadow relief comprising the step of generating a shadow relief by converting the stereoscopic terrain synthesized by the screen shading source into a 2D image photographed from a point of view disposed at an arbitrary position in a 3D space. to provide.

In addition, the compositing in the screen shading source synthesizing step is performed on the whole of the stereoscopic terrain by multiplying the brightness of an arbitrary area of the stereoscopic terrain with the brightness of a region corresponding to the arbitrary area of the screen shading source. do.

In addition, the elementary shading source selects any one of the contours between the high altitude contours (hereinafter, low altitude contours) and any adjacent high altitude contours inside the low altitude contours, and the low altitude contours and the high altitudes. A plurality of virtual contours are set with reference to the slope of the terrain between the contours, and for each of the plurality of virtual contours, a brightness that gradually brightens from the brightness of the shadow set in the low altitude contour to the brightness of the shadow set in the high altitude contour. By imparting a shadow having a shape, it has a shadow shape that gradually brightens from the lowest altitude to the highest altitude according to the elevation of the three-dimensional terrain.

In addition, the three-dimensional terrain generation step, the lighting arrangement step of placing an illumination source on one side of the three-dimensional space in which the three-dimensional terrain exists; And applying lighting to represent the shadow according to the illumination on the three-dimensional terrain.

The screen shading source synthesizing step may include: a color source preparation step of preparing a color source to which an arbitrary color is given based on the elevation of the target terrain based on the contour line; And a color source overlapping step of overlapping the color source with the stereoscopic terrain to which the screen shading source is synthesized.

In addition, the overlapping of the color source overlapping may include adding a color of an area of the stereoscopic terrain to which the screen shading source is synthesized and a color of an area corresponding to the random area of the color source. Is performed against.

The screen shading source synthesizing step may include two-dimensional information projecting two-dimensional information including hiking trail information, road information, and location information of the terrain selected in advance onto the three-dimensional terrain synthesized with the screen shading source. Projection step; And a two-dimensional information correcting step of correcting positional inconsistencies caused by projecting the two-dimensional information on the three-dimensional terrain that is three-dimensional.

In addition, the present invention provides a device for generating a shadow relief: storing the circularity represented by the two-dimensional contour lines of the relief of any target topography that will produce a shaded relief map in which the height difference of the terrain is expressed three-dimensionally three-dimensionally; Obtain a circle from a geospatial database, extract the closed curves by the contours from the circle, give the dark curve with the first brightness of black, and give the highest The closed curves of the contours are given bright shades having a second brightness of white, and the contours of the altitudes formed between the lowest and highest elevations are given shades having brightness between the first brightness and the second brightness. A basic shade source generator for generating a basic shade source; A three-dimensional terrain generation unit configured to generate a three-dimensional stereoscopic terrain having a higher altitude as a portion having the first brightness as a floor and closer to the second brightness according to the brightness of each part of the basic shadow source; A screen shade source generator for generating a screen shade source by reversing the brightness of the basic shade source; By synthesizing the generated stereoscopic terrain and the screen shading source, the higher brightness portion of the screen shading source transmits less of the contour of the stereoscopic terrain, and the lower brightness portion of the screen shading source sharpens the contour of the stereoscopic terrain. A screen shading source synthesizing unit for transparently transmitting; And a shade relief degree generating unit configured to generate the shade relief by converting the stereoscopic terrain synthesized with the screen shading source into a 2D image photographed from a viewpoint disposed at an arbitrary position in a 3D space. to provide.

By such a procedure, the shaded relief map manufacturing method and apparatus according to an embodiment of the present invention, the relief of the terrain is expressed in a lively and realistic, and the colors are beautifully expressed, and can be produced a shaded relief map accurately displayed a variety of information Will be.

1 is a block diagram showing the configuration of a shadow relief manufacturing system according to an embodiment of the present invention.
2 is a flowchart illustrating a method of manufacturing a shadow relief according to an embodiment of the present invention.
2 is a flowchart illustrating a method of manufacturing a shadow relief according to an embodiment of the present invention.
4 is a flowchart illustrating a method of applying a shadow effect to lighting on a three-dimensional terrain.
5 is a flowchart for explaining a method of applying a color source.
6 is a flowchart illustrating a method of adding various pieces of information to a stereoscopic terrain synthesized with a screen shading source.
7 is a diagram illustrating an example of a circle and a basic shading source generated from the circle.
8 is a view for explaining a form of arranging an illumination source in a three-dimensional space.
9 is a diagram illustrating an example of a stereoscopic terrain in which the generated color source and the color source are overlapped with the stereoscopic terrain to which the screen shading source is synthesized.
FIG. 10 is a diagram illustrating an example of three-dimensional terrain on which two-dimensional information and two-dimensional information prepared from a circle diagram are projected.
11 is an example of the shadow relief produced by a conventional method.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in more detail.

1 is a block diagram showing the configuration of a shadow relief manufacturing system according to an embodiment of the present invention. According to FIG. 1, the shadow relief map production system includes a geographic information database 10 and a shadow relief map production device 20. In particular, the shadow relief map production device 20 includes a basic shadow source generation unit 22. ), The stereoscopic terrain generator 23, the screen shade source generator 24, the shadow synthesizer 25, and the shadow relief generator 26.

The geographic information database 10 is a database that stores a basic map published by the National Geographical Institute. In such a geographic information database 10, various types of information such as road information, geological information, and environmental information are digitized and stored. This information is represented numerically on a map produced in a vertical view from the air. A two-dimensional map containing information expressed in numerical values is called a numerical diagram. Hereinafter referred to as "circleness".

The basic shadow source generator 22 in the shadow relief map manufacturing apparatus 20 receives the source map from the geographic information database 10, and then uses the contour lines displayed on the map to view the target terrain displayed on the map. Create a default shading source to represent in dimensions. The basic shading source is widely used to produce a general three-dimensional solid figure, and a brief description of the generation method is as follows.

First, each closed curve is extracted by a plurality of contours from a circle. At this time, the contour line must have the shape of a closed curve, but the portion cut by the edge of the circle is preferable to assume the edge of the circle as the contour line to complete the closed curve.

With reference to the extracted contours, the lowest and lowest altitudes are identified, and dark shades having a first brightness of black are given to the inside of the closed curve by the contours having the lowest altitudes, Closed curves by contours are given bright shades with a second brightness of white, for example, and contours for one or more altitudes placed between this minimum and this highest altitude have black (first brightness) and A basic shaded source is created by giving a shade of grayscale with brightness between white (second brightness).

On the other hand, for a plurality of altitude contours arranged between the lowest and highest altitudes, the brightness is gradually set to become higher and lower from the lower altitude (low altitude) to the higher altitude (high altitude), thereby giving the highest and lowest altitudes. Make it appear brighter at higher and higher levels.

When a shadow source is generated in this manner, since the contour lines are usually displayed in units of 10 m or 20 m, the shadows given to one contour line and the shadows given to the contour lines adjacent to the contour lines appear in a stepped form. However, if you create a shading source in such a step shape, the three-dimensional terrain to be formed using this shading source (base shading source) appears as an unnatural step in the form of a step, so it is necessary to naturally change the brightness of the shade between each contour line. have.

For this purpose, a shading source is generated by the method as shown in FIG. 3 is a diagram illustrating a process of generating a basic shading source. First, one of the contours (low altitude contours) and the high altitude contours placed immediately inside the low altitude contours is selected, and each contour is made into a vector image. A virtual layer with numerous height values is created between the low and high contours of the vector image, and each layer is given a shadow having brightness between the brightness set in the low altitude contour and the brightness set in the high altitude contour.

In other words, if the low altitude contour is selected as 100m contour and the altitude contour is selected as 110m contour, the 100m contour is applied with the brightness set to 40% and the 110m contour is applied with the brightness set to 30%. Ten contour lines can be set virtually in 1m increments between 110m contour lines, and each contour line can be shaded while decreasing brightness by 1%. In other words, the 101m contour sets the brightness to 39% and the 102m contour applies the brightness to linearly decrease, such as the brightness to 38%.

Although setting up 10 virtual contours between low and high contours is described, setting the number of 100 or more can further reduce the stepped shape of the shadow source, resulting in the highest altitude from the shadow of the lowest altitude contour. You will be able to create shaded sources (primary shaded sources) whose brightness gradually changes naturally to the contours of the contours.

The three-dimensional terrain generation unit 23 three-dimensionally generates the terrain that the basic shadow source targets in the virtual three-dimensional three-dimensional space by using the generated basic shadow source. That is, the first brightness portion expressed in black is used as the bottom surface of the basic shaded source, and the second brightness portion represented in white is made normal, thereby generating a three-dimensional terrain having a shape that rises as the brightness value increases.

In addition, the three-dimensional terrain generation unit 23 includes a function of giving a shadow effect by virtual illumination to the three-dimensional terrain generated by the basic shadow source.

The shadow effect is the opposite slope of the illumination source in the three-dimensional terrain when the lighting source is placed anywhere in the virtual three-dimensional space that created the three-dimensional terrain, and the rays of arbitrary color and brightness are directed toward the three-dimensional terrain. To express the shadows on

At this time, the illumination source may be assumed to be the sun on the actual target terrain, but a plurality of illumination sources may be set to better represent the ups and downs of the terrain in the shadow relief.

The screen shade source generator 24 generates a screen shade source using the basic shade source generated by the basic shade source generator 22. Screen shading sources are created by simply inverting the brightness of the base shading source.

The shadow combining unit 25 synthesizes the screen shading source to the three-dimensional terrain generated by the basic shading source.

The screen shading source is generated by simply inverting the brightness of the basic shading source in this way, but performs a completely different function from the basic shading source which generates three-dimensional terrain that rises or sinks according to the brightness.

In other words, the screen shading source serves to make the contour of the stereoscopic terrain appear sharp and blurred according to the brightness value of each region. More specifically, map the screen shading source to match the shape of the stereoscopic terrain, and the higher brightness portion of the screen shading source transmits less of the contour of the stereoscopic terrain, and the lower brightness portion of the screen shading source outlines the contour of the stereoscopic terrain. Clear transmission As a result, the terrain with high altitude is clearly visible, and the terrain with low altitude is blurred or invisible.

In this case, the composition of the stereoscopic terrain and the screen shading source may include a color (or brightness) of an arbitrary area of the stereoscopic terrain and an area corresponding to the arbitrary area of the screen shading source mapped with the screen shading source mapped to the stereoscopic terrain. This is done by multiplying the brightness of, by setting an arbitrary area for the entire three-dimensional terrain and performing a corresponding operation.

As described above, according to the process of synthesizing the screen shading source to the three-dimensional terrain, the two-dimensional information (described later) displayed on the three-dimensional terrain is more clearly expressed, which is easier to see by the user, and furthermore, the two-dimensional image (described later). When you complete the shadow relief by converting to), the terrain becomes more lively and realistic.

In addition, the shadow combining unit 25 may include a function of applying an arbitrary color to the three-dimensional terrain to which the screen shading source is applied.

To this end, the shadow combining unit 25 may receive a color source from the outside. The color source may be inputted by the shadow relief maker directly, or may be generated by the color source generator with an additional color source generator (not shown) in the shade relief device 20 according to an embodiment of the present invention. One outcome can be applied.

The color source imparts an arbitrary color to every closed curve due to the contour of the original degree, and overlaps the stereoscopic terrain as it is so that the altitude of the stereoscopic terrain can be surely expressed visually.

In this case, the overlapping of the color source may be performed by adding a color (or brightness) of an area of the stereoscopic terrain to a color corresponding to the arbitrary area in the mapped color source after the screen shading source is mapped to the stereoscopic terrain. This is done by setting an arbitrary region for the entire three-dimensional terrain and performing a corresponding operation.

By applying the color by the color source to the three-dimensional topography after the screen shadow source is applied in this way, the color of the three-dimensional topography can be clearly expressed without being distorted by the illumination light.

That is, in the conventional shadow relief, the color source is applied to the three-dimensional terrain generated by the basic shadow source, and then the shadow effect is given by illumination. According to this process, there is a problem in that the part having a strong shadow effect is different in color from the non-part and the color source. However, by applying the color source after all the lighting effects (shadow effects) are applied as in the present invention, it is possible to prevent the color distortion as in the conventional method.

The shadow relief generating unit 26 synthesizes a screen shadow source so that the high altitude terrain is clearly seen and the low altitude terrain is blurred or invisible three-dimensional terrain in an arbitrary position in the virtual three-dimensional space. The image is converted into a two-dimensional image as viewed from the viewpoint arranged at the. This two-dimensional image is a shaded relief map that merely represents the ups and downs of the terrain without any additional geographic information.

In addition, the shaded relief generation unit 26 projects two-dimensional information including hiking trail information, road information, terrain location information, and the like previously examined on the target terrain before converting the image into a two-dimensional image. And a function for correcting positional inconsistencies caused by projecting information onto three-dimensional terrain.

As such, by generating a two-dimensional image using the three-dimensional terrain on which the two-dimensional information is projected, a shaded relief degree in which various information is represented is completed.

Next, a method of manufacturing the shaded relief degree by the shadow relief degree manufacturing system according to an embodiment of the present invention as described above will be described. Details of each step may be understood by referring to the above description.

2 is a flowchart illustrating a method of manufacturing a shadow relief according to an embodiment of the present invention. First, the shadow relief maker prepares a circle from the geographic information database 10 (S10), extracts the contour from the prepared circle and generates a basic shadow source (S20). An example of the circle is shown in FIG. 7A, and an example of a basic shading source generated from the circle can be understood with reference to FIG. 7B.

The basic shading source is used to generate three-dimensional terrain (S30), and synthesizes the screen shading source generated by using the basic shading source to the three-dimensional terrain generated (S40, S50). An example of the three-dimensional terrain generated by the default shading source is shown in FIG. 7C, an example of the screen shading source may refer to 7d, and the three-dimensional terrain in which the screen shading source is synthesized is shown in FIG. 7E.

Subsequently, the shadow relief is generated by capturing the stereoscopic terrain synthesized with the screen shading source by converting the stereoscopic terrain into a two-dimensional image by using a virtual camera disposed at an arbitrary viewpoint in the stereoscopic space (S60).

3 is a diagram illustrating a process of generating a basic shading source, in which a dark shade is given to a closed curve due to any one of low altitude contours, and a light shade is given to a closed curve due to adjacent high altitude contours at the top. Giving.

In the middle of FIG. 3, a virtual contour line is set between the low altitude contour line and the high altitude contour line, and the virtual contour lines are shaded so that the brightness is changed sequentially.

In the lower part of FIG. 3, the shade source represented by the brightness that is softly changed by the above virtual contour line is generated.

4 is a flowchart illustrating a method of imparting a shadow effect by illumination to a three-dimensional terrain. The shadow effect is preferably imparted immediately after generating the solid terrain by the underlying shading source.

That is, when the three-dimensional terrain is generated by the three-dimensional terrain generation step of FIG. 2 (S31), the illumination source is placed at an arbitrary position in the three-dimensional virtual space including the three-dimensional terrain (S32), and the illumination is arranged by the arranged illumination source. By applying the shadow effect to the three-dimensional terrain (S33).

In this case, one or more illumination sources may be disposed.

The arrangement of the illumination source in the three-dimensional space as shown in Figure 4 can be understood with reference to FIG.

5 is a flowchart for explaining a method of applying a color source. The color source of FIG. 5 is overlapped after step S50 of FIG. 2 is performed.

First, in FIG. 5, a color source generating unit (not shown) generates a color source by applying a predetermined color according to an altitude using a closed curve by contour lines of a circle (S51). An example of the generated color source may refer to FIG. 9A. Subsequently, the generated color source is overlaid on the stereoscopic terrain to which the screen shading source is synthesized (S52), thereby coloring the stereoscopic terrain. An example of a three-dimensional terrain in which a color source is overlapped is shown in FIG. 9B.

The color source may be set such that the height difference can be easily distinguished by color, for example, by giving different colors on the basis of every 50m contour line. Or it may be generated in a color that gradually changes from the lowest altitude region to the highest altitude region.

Thus, by overlapping the color source after step S50, the color is applied after the shadow effect by the illumination light has already been applied to the three-dimensional terrain, so that the distortion of the applied color can be minimized.

6 is a flowchart illustrating a method of adding various pieces of information to a stereoscopic terrain synthesized with a screen shading source. In fact, in order for the user to use the shadow relief according to an embodiment of the present invention, not only the shape of the terrain but also the roads, structures, vegetation, geological structures, etc. formed on the target terrain should be visually represented. Therefore, letters, symbols, figures, colors, and the like representing such information must be represented on the shaded relief. On the other hand, such information may be extracted and created from the original diagram.

This information, that is, the two-dimensional information extracted from the originality, is projected on the three-dimensional terrain to which the screen shading source is applied (S55, S56), and the two-dimensional information projected by the maker of the shadow relief is projected and displayed at the correct position. It is corrected (S57).

An example of the 2D information prepared from the original diagram is shown in FIG. 10A, and an example of the three-dimensional terrain on which the 2D information is projected is shown in FIG. 10B.

By such a procedure, the shaded relief map production apparatus according to an embodiment of the present invention, the relief of the terrain can be produced with a lively and realistic, the colors are beautifully expressed, and various information is accurately represented shaded relief map .

10: Geographic Information Database
20: shading relief map production device
22: default shading source generator
23: three-dimensional terrain generation unit
24: screen shading source generator
25: shading composition
26: shaded relief generation unit

Claims (8)

A circularity preparation step of preparing a circularity in which two-dimensional contours represent the ups and downs of an arbitrary object topography that will generate a shaded relief degree in which the height difference of the terrain is three-dimensionally represented;
Extracting the closed curves by the contours from the circle, giving the dark curve having the first black brightness to the closed curve by the contour of the lowest elevation, and the second brightness of white to the closed curve by the highest elevation Generating a basic shadow source having a light shade having a brightness having a brightness between the first brightness and the second brightness in the contour of the altitude between the lowest and the highest altitudes; ;
A three-dimensional terrain generation step of generating a three-dimensional stereoscopic terrain having a higher altitude as a portion having the first brightness as a floor according to the brightness of each part of the basic shading source, and having a brightness closer to the second brightness;
Generating a screen shadow source by inverting brightness of the basic shadow source;
By synthesizing the generated stereoscopic terrain and the screen shading source, the higher brightness portion of the screen shading source transmits less of the contour of the stereoscopic terrain, and the lower brightness portion of the screen shading source sharpens the contour of the stereoscopic terrain. Screen shading source synthesis step of transmitting transparently;
A shadow relief generation step of generating a shadow relief by converting the stereoscopic terrain synthesized with the screen shadow source into a 2D image photographed from a viewpoint disposed at an arbitrary position in a 3D space. . The method of claim 1,
The synthesis in the screen shading source synthesis step,
And multiplying the brightness of an arbitrary region of the three-dimensional terrain by the brightness of an area corresponding to the arbitrary region of the screen shading source, for the entirety of the three-dimensional terrain. The method of claim 1,
The default shading source is,
Select any one of the contours (hereinafter, low altitude contours) and any adjacent high altitude contours inside the low altitude contours, and refer to the slope of the terrain between the low altitude contours and the high altitude contours. By setting a plurality of virtual contours, and giving each of the plurality of virtual contours a shadow having a brightness which gradually brightens from the brightness of the shadow set in the low altitude contour to the brightness of the shadow set in the high altitude contour. Method of producing a shaded relief characterized in that it has a shade form that gradually brightens from the lowest altitude to the highest altitude according to the altitude of the terrain. The method of claim 1,
The three-dimensional terrain generation step,
An illumination arrangement step of arranging an illumination source on one side of the three-dimensional space in which the three-dimensional terrain exists;
And applying lighting to represent the shadow according to the illumination on the three-dimensional terrain. The method of claim 1,
The screen shading source synthesis step,
A color source preparing step of preparing a color source to which an arbitrary color is given according to the altitude of the target terrain based on the contour line;
And a color source overlapping step of overlapping the color source with the stereoscopic terrain to which the screen shading source is synthesized. The method of claim 5,
The overlapping of the color source overlapping step is
The shadow shading degree fabrication is performed on the entirety of the three-dimensional terrain by combining the color of an arbitrary region of the three-dimensional terrain with the screen shading source synthesized and the color of the region corresponding to the arbitrary region of the color source. Way. The method of claim 1,
The screen shading source synthesis step,
A two-dimensional information projection step of projecting two-dimensional information including at least one of hiking trail information, road information, and terrain location information previously examined on the target terrain onto the three-dimensional terrain synthesized with the screen shading source;
And a two-dimensional information correcting step of correcting positional inconsistencies caused by projecting the two-dimensional information onto the three-dimensional terrain of three-dimensional terrain. As a device for generating shadow relief:
Obtaining the original degree from the geographic information database storing the original degree representing the ups and downs of any target topography in two-dimensional contours, in which the elevation difference of the terrain is to create the three-dimensional three-dimensional shaded relief. Extract the closed curves by the contours, give the dark curves with the first brightness of black to the closed curves by the lowest elevation, and give the bright curves with the second brightness of white to the closed curves by the highest elevation And a basic shading source generator configured to generate a basic shading source having a shade having a brightness between the first brightness and the second brightness on the contour of the altitude formed between the lowest altitude and the highest altitude;
A three-dimensional terrain generation unit configured to generate a three-dimensional stereoscopic terrain having a higher altitude as a portion having the first brightness as a floor and closer to the second brightness according to the brightness of each part of the basic shadow source;
A screen shade source generator for generating a screen shade source by reversing the brightness of the basic shade source;
By synthesizing the generated stereoscopic terrain and the screen shading source, the higher brightness portion of the screen shading source transmits less of the contour of the stereoscopic terrain, and the lower brightness portion of the screen shading source sharpens the contour of the stereoscopic terrain. A screen shading source synthesizing unit for transparently transmitting; And
And a shadow relief generating unit for generating the shadow relief by converting the stereoscopic terrain synthesized with the screen shadow source into a 2D image photographed from a viewpoint disposed at an arbitrary position in a 3D space. .

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