KR101103340B1 - Geographic Information analysis method using of Viewshed Frequency analysis - Google Patents

Abstract

The present invention relates to a method for analyzing geographic information using visible frequency analysis, comprising: (a) selecting a viewing target point of a multi-layer structure; (b) calculating numerical data by viewshed analysis for each view target point; (c) summing the numerical data calculated at the viewpoint targets of each floor to complete a visible frequency table; And (d) calculating a video image based on the visible frequency using the visible frequency table.
When the present invention is provided, stereo stereoscopic analysis is possible by multiple points, and thus, an analysis result can be obtained, which is improved compared to the existing visual field analysis, and regardless of the size of the target site through the multi-grid grid point viewing target selection method. More accurate results can be obtained through the pre-processing process for creating a DEM that reflects the height of the building or the post-processing process using the regular vegetation index for the treatment of visual obstacles.

Description

Geographic Information analysis method using of Viewshed Frequency analysis}

The present invention relates to a method for analyzing geographic information, and more particularly, to a method for analyzing geographic information using visible frequency analysis for precisely analyzing various types of geographic information.

Since the urban landscape looks different depending on the location of observation, it is more efficient to establish the main observation point and plan based on this. In other words, it would be ideal to manage the scenery from all points beautifully, but this is almost impossible in an urban environment where various structures are densely packed. Therefore, it is inevitable in modern cities to select major viewpoints and develop landscape management plans around them.

The selection of viewpoints goes through various processes depending on the nature of the purpose of analysis and the characteristics of the site, but in general, it is generally made in the order of the selection of perspective objects, the analysis of the right of view, the setting of distance and direction criteria, the view opportunity and the landscape beauty analysis.

Among them, viewshed analysis is a technique that analyzes the visible area in which the viewing object is observed through computer simulation, and can be called an analysis method introduced to give objective rationality of selecting a viewing point.

In recent years, the generalization of the Geographic Information System (GPS) has made it possible to easily analyze the visibility even without a programmer or an expert.In Korea, many examples of the use of landscape impact factors in the landscape field of environmental impact assessment are used as basic data. Can be.

As such, visibility analysis is used in various aspects of the landscape field to ensure objective rationality, but any analysis based on visibility analysis ignores limitations of DEM (e.g. height error, earth curvature), ignores visual obstacles (e.g. vegetation, dry environment), It cannot be free from the effects on the atmospheric environment, the viewer's visibility, and unfortunately most of the visibility analysis applications do not adequately reflect these technical issues.

First, since the analysis procedures and calculation methods of most of the GIS programs used in the prior art are not disclosed, it is impossible to improve the performance of visual analysis or to extract additional data. For example, there is a problem that the user cannot arbitrarily correct an error due to the earth curvature or the refraction error of the light due to the air layer, and cannot extract additional data such as the incident angle of the viewing angle.

Second, the general input data used for the analysis of the right of view is analyzed based on the contour and elevation point of the digital map, so it is possible to analyze the visible area in the case of a single artificial structure, but in case of targeting a large area such as a large complex or a new city, It remains to be questioned whether the choice of viewing point can represent a wide area.

Among the problems mentioned above, the question about the representativeness of the selection of the target point of view is taken as a methodological problem recognition, leaving the dimension of precision problem recognition, meaning that it cannot be analyzed for a relatively large object by the conventional analysis method.

An object of the present invention to solve the above problems is to enable stereo three-dimensional analysis to obtain an improved analysis results than the existing visibility analysis, and to analyze the terrain of various forms regardless of the size of the target site, The purpose of this paper is to provide a method for analyzing geographic information that can obtain more sophisticated geographic information.

A first aspect of the present invention for solving the above problems is (a) selecting a viewing target point of the multi-layer structure; (b) calculating numerical data by viewshed analysis for each view target point; (c) summing the numerical data calculated at the viewpoint targets of each floor to complete a visible frequency table; (d) calculating a video image based on the visible frequency using the visible frequency table.

Here, the selection of the viewing target point in the step (a) is to select the target point for each layer by a lattice point selection method of forming a multi-layer in a plurality of vertical directions, the numerical data of the step (b) Calculating step is preferably using a digital elevation model (DEM).

In addition, the step (c) may include a step of creating a table by digitizing the visible region and the invisible region by a visible analysis for each view target point of each layer; And summing the numerical tables of the respective layers to form a visible frequency table of the investigation target area, wherein the algorithm of the viewshed analysis is based on a reference plane method. In this case, a point-to-point method may be used in combination with a point of view close to the point of view, and the data for the point of view may include the viewpoint height of the observer, the height of the viewing object, the observation azimuth angle, and the observation. Vertical angle and observation radius data may be used.

A second aspect of the present invention is to provide a method for selecting a viewing target point of a multilayer structure; (b) calculating numerical data by viewshed analysis for each view target point; (c) summing the visible numerical values calculated at the viewpoint targets of the respective floors to complete a visible frequency table; (d) post-processing using a normalized difference vegetation index (NDVI) result value in the visible frequency table; And (e) calculating a video image based on the visible frequency using the post-processed visible frequency table.

Here, the selection of the viewing target point in the step (a) is to select the target point for each layer by a lattice point selection method of forming a multi-layer in a plurality of vertical directions, the numerical data of the step (b) Calculating step is preferably using a digital elevation model (DEM).

Preferably, the digital altitude model may be to calculate a numerical value pre-processed by reflecting the height value of the artificial structure, the step (c), the visibility analysis (Vieshwed analysis) for each viewing point of each layer Digitizing the visible region and the invisible region to create a table; And summing the numerical tables of the respective layers to form the visible frequency table of the irradiation target area.

The algorithm of the viewshed analysis is based on a reference plane method, and uses a point-to-point method in combination with a near point of view for the viewing point. Preferably, the data on the viewing target point is preferably using the observer viewpoint height, the viewing target height, the observation azimuth angle, the observation vertical angle and the observation radius data.

When the present invention is provided, stereo stereoscopic analysis is possible by multiple points, and thus, an analysis result can be obtained, which is improved compared to the existing visual field analysis, and regardless of the size of the target site through the multi-grid grid point viewing target selection method. More accurate results can be obtained through the pre-processing process for creating a DEM that reflects the height of the building or the post-processing process using the regular vegetation index for the treatment of visual obstacles.

1 is a flowchart illustrating a method for analyzing geographic information using visible frequency analysis according to the present invention;
FIG. 2 is a diagram illustrating a conceptual diagram of visibility analysis described as a line of sight (LOS). FIG.
3 is a view showing a conceptual diagram of selecting a viewing target point of a multi-layer structure applied to an embodiment according to the present invention;
4 is a view showing a schematic diagram of a calculation method of the visible frequency analysis applied in the embodiment according to the present invention,
5 is a view illustrating a photograph comparing the visibility analysis and the visibility analysis applied in the embodiment of the present invention,
6 is a schematic diagram of a mixing algorithm of a reference plate method and a point-to-point method applied in an embodiment according to the present invention;
7 is a view showing a conceptual diagram of a reference plate method applied in an embodiment according to the present invention;
8 is a flowchart illustrating a method for analyzing geographic information using visible frequency analysis to which pre and post processing is applied as another embodiment according to the present invention;
Figure 9 is a photograph showing the results of the analysis of the visibility based on the DEM reflecting the height of the building and one of the general DEM to the same point in the downtown area using an embodiment of the present invention,
10 is a photograph showing the results of the visibility analysis after processing using the vegetation index for Daegu Innovation City using an embodiment according to the present invention,
11 is a view showing the visible frequency analysis diagram of the Daehyun easy world in the analysis method according to the present invention,
FIG. 12 is a diagram showing an analytical diagram without pretreatment and an analytical diagram with pretreatment in the visible frequency analysis of the Daehyun Easier World, which is the same region as in FIG. 11;
Figure 13 is a photograph showing the visible frequency analysis of the Daegu Sinam redevelopment and maintenance district using an embodiment according to the present invention,
Figure 14 is a photograph showing the visible frequency analysis of Daegu Innovation City using an embodiment according to the present invention,
15 is a photograph showing the visible frequency analysis of the Gyeongju new history zone using an embodiment according to the present invention.

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

1 is a diagram illustrating a flowchart of a method for analyzing geographic information using visible frequency analysis according to the present invention. As shown in Figure 1, the present invention comprises the steps of (a) selecting the viewing target point of the multi-layer structure; (b) calculating numerical data by viewshed analysis for each view target point; (c) summing the numerical data calculated at the viewpoint targets of the respective layers to complete the visible frequency table; And (d) calculating a video image based on the visible frequency using the visible frequency table.

As described above, the present invention uses digital elevation model (DEM) to form numerical data through visual field analysis, and the most important viewing point is not a single point on a plane or a plurality of lattice points made of multiple layers. An analysis method that calculates the image of the landscape by performing visible frequency analysis by performing visible-rights analysis as a viewing point, summing the numerical data formed at each grid point, and dividing the visible and non-visible areas in more detail. Suggest. That is, the present invention proposes a visible frequency analysis method for obtaining a visible frequency through arithmetic overlap of the visible region calculated at multiple landscape target points.

Hereinafter, the visibility analysis and the visibility frequency analysis applied in the present invention will be described in detail.

The present invention proposes a visible frequency analysis method in order to improve the visibility analysis method for selecting a viewpoint, and implements and applies it by programming and proceeds to the following steps.

First, the concept of trail frequency analysis: Based on the understanding of visibility analysis, the concept of visible frequency analysis that can visually express the frequency of visible region is established.

Second, the design and implementation of the visible frequency analysis: As an implementation stage of the established visible frequency analysis, it adopts the interface of the existing program and implements it through customization.

Third, the application and comparative evaluation of the target site: The target site determines the size of apartment complex development, district unit size development, new city size development, etc. according to the size of development and the location of the development site. Analyze the method.

FIG. 2 is a diagram illustrating a concept of visibility analysis described by line of sight (LOS). FIG. As shown in FIG. 1, the visual field analysis calculates whether a line of sight (LOS) is blocked between an observer's viewpoint and a target based on digitized digital information (DEM) to determine the visible and invisible regions. Analytical method to derive.

The application examples are as shown in [Table 1], such as the installation of cell phone base station antennas or shortwave radio antennas (Ray 1994, Llobera 2003), and the field of landscapes such as forest deforestation or open-pit mining management and landscape impact analysis. 1994), military sectors, such as the location of missile bases or station locations (Franklin 2002), tourism sectors, such as the establishment of touristic routes, or even the design of wide-area networks for lunar colonies without ionos, or to secure wider exploration areas. It is used in a wide variety of applications, including space exploration areas, such as the planning of landing points for Mars probes (Franklin 2002).

Among them, the use of the landscape field is very influential in that the landscape is visible, that is, the field that deals with the landscape, and is expected to be used more widely in the future.

For this reason, the present invention has been conceived from the question whether the visible analysis analyzed at a single viewing point can represent a wide range of objects. In other words, the analysis of the visibility of independent structures or clustered buildings is not unreasonable even by the analysis by a single viewpoint like the existing method. However, finding a single viewing point that represents a relatively large destination such as a large apartment complex or a new town is almost impossible. An easy solution to this may be to select and analyze multiple viewpoints.

[Table 2] shows examples that can be suggested in selecting the view point according to the shape of the site and the change of the terrain inside and outside. The single point selection method has the advantage that the analysis is simple and easy when the multi-site is wide and open plain and the shape is circular. However, in the case of Korea's topography, it can be used only in some special new town planning considering the characteristics of mountainous area more than 70% and the surrounding drying environment.

On the other hand, the boundary point selection method can be used when the shape of the target site is branched and when the surrounding terrain is severely changed (branched city). Lastly, in the case of grid point selection method, it is possible to analyze even terrain with severe topographical changes in mountainous terrain both inside and outside of the target site, and it does not have to be concerned with the topographical characteristics. Therefore, more accurate results can be expected by using lattice point selection method with high latitude on all terrains.

3 is a diagram showing a conceptual view of selecting a viewing target point of a multi-layer structure applied to an embodiment according to the present invention. As shown in FIG. 3, the vertical consideration was solved in a multilayered structure further from the selection of a plan view target point. Since the height of the building, which can be actually built, is not known at the initial planning stage, multi-layered view point selection is a more flexible solution.

As described above, the method of selecting a lattice point viewing object having a multi-layer structure applied in the present invention may be effective for the analysis of the visibility of a relatively large object, but the problem is that the object point to be analyzed increases exponentially according to the area of the object.

Therefore, the present invention intends to solve the problem by visual frequency analysis that expresses each result as a frequency. 4 is a view showing a schematic diagram of a calculation method of the visible frequency analysis applied in the embodiment according to the present invention. As shown in FIG. 4, the result of the visibility analysis is represented by the binary method of visibility (see FIG. 4 (a)). When these analysis results are overlapped (summed) as shown in FIG. This is how many individual cells are visible from the point of view.

In other words, the view frequency analysis (viewshed frequency analysis) is represented by the frequency distribution by arithmetic operation of the visibility analysis by multiple points. Unlike conventional visibility analysis, such visibility frequency analysis is meaningful in that it can determine the important visibility position because it is expressed not only by visibility but also by frequency, thereby improving the quality of analysis. (See Fig. 5)

As such, the present invention encounters some problems when entering the implementation stage based on the concept of visible frequency analysis. One of the typical ones is that most of the visibility analysis applications are not optimized for performing the visible frequency analysis. . This is a cumbersome task that needs to be reviewed, from algorithms in visibility analysis to design and implementation. Therefore, in this study, the algorithm review was made public in order to make the best use of the existing research results, and it was customized by borrowing the interface of the existing GIS program at the implementation stage.

Visibility analysis algorithms include the point-to-point method (Huss and Pumar, 1997), the vector-analysis method (Sorensen and Lanter, 1993), and the reference plane method (Wang et al., 2000). ) Has already been established.

As shown in Table 3, it is difficult to find an algorithm that satisfies both computation speed and accuracy. Therefore, in the present invention, a point-to-point method is used in combination with the reference plane method in consideration of the computation speed. A diagram showing a schematic diagram of a mixing algorithm of a reference plate method and a point-to-point method applied in an embodiment according to the present invention.

7 is a view showing a conceptual diagram of the reference plate method applied in the embodiment according to the present invention. As shown in FIG. 7, in the reference plate method, as shown in FIG. 7, the plane formed by the three points of the viewpoint S and the reference points r _{m-1, n + 1} , r _{m , n + 1} is the estimated height of the terrain d _{m , n} and If the relationship is greater than the height of the terrain as shown in (a) of FIG. 7, it is determined as the visible area, and the terrain height d _{m , n} is stored as the reference value r _{m, n} and used as a reference value of the next target point. In addition, as shown in (b) of FIG. 7, when the height of the reference plate is higher, it is determined as an invisible region and a simple algorithm for storing the height Z of the reference plate as the reference values r _{m and n} .

The reference plate method may accumulate initial error values close to the view point, and thus, a higher analysis method may be configured by substituting the point near point method.

In addition, visibility analysis is an essential function to perform visibility analysis. However, most of the existing visibility analysis programs do not support 16 or more multiple visibility analysis, and thus cannot be optimized. Therefore, the present invention has been implemented by creating a model using a direct program.

The observer viewpoint data used here considers the observer viewpoint height, viewing object height, observation start and end azimuth angle, observation vertical angle and observation radius as shown in [Table 4], and used the ArcGIS method of inputting as attribute data. .

In addition, the error due to the earth curvature is also called a gradient, and refers to the difference between the height of the horizontal line and the level line caused by the earth's curvature due to the error of the earth's curvature, as shown in [Equation 1].

[△ h1: Difference, S: Distance between two points, R: Earth radius]

The error of refraction of light by the atmosphere is also referred to as a train, and refers to an error in which light is refracted by a change in refractive index caused by a difference in density of the atmospheric layer.

[△ h2: train, K: refraction coefficient (0.12 ~ 0.14), S: distance between two points, R: radius of earth]

Since this error correction is proportional to the square of the distance S between two stations, it can be ignored when the radius of the target is not large, but it should be considered when the target is large.

Also, as mentioned in the algorithm selection, the number of rings to which the point-to-point algorithm is applied is used to determine the number of rings. to be.

8 is a flowchart illustrating a method for analyzing geographic information using visible frequency analysis to which pre and post processing are applied according to another embodiment of the present invention. As shown in Figure 8, the present invention comprises the steps of (a) selecting the viewing target point of the multi-layer structure; (b) calculating numerical data by viewshed analysis for each view target point; (c) summing the visible numerical values calculated at the viewpoint targets of the respective floors to complete a visible frequency table; (d) post-processing using a normalized difference vegetation index (NDVI) result value in the visible frequency table; And (e) calculating a video image based on the visible frequency using the post-processed visible frequency table.

As described above, the embodiment of the present invention differs from the embodiment shown in FIG. 1 in the calculation of the numerical data for visual analysis, considering the height of the artificial structure, or evaluating the vegetation index for measuring the vitality of the plant to evaluate the post-processing method. By further adding, the present invention proposes an embodiment in which the geographic information can be more precise and an analysis suitable for various terrain information can be implemented. In the following, the description of the method of selecting the viewing target point or the visibility frequency analysis method, which is applied in the same manner as in FIG.

In order to determine the usefulness of the visibility analysis and the comparative analysis with the visibility analysis implemented through the embodiment of the present invention, considering the development scale and the location of the development, the apartment complex size development, district unit size development, new town scale development zone were defined, and analysis. In order to improve the accuracy of the data, pre and post data processing was performed.

1. Preprocessing of Terrain Information

DEM (Digital Elevation Model) data, which is the topographical information used for visual field analysis, is generally produced based on height data extracted from contours and elevations on digital maps. This may be suitable terrain data in mountainous terrain where artificial structures are relatively rare, but not suitable terrain data in areas consisting of artificial structures such as urban areas.

FIG. 9 is a photograph showing the results of visual field analysis based on a DEM reflecting the height of a building, one of which is a general DEM and the other of which targets the same point of a city center using an embodiment of the present invention. As can be seen from the analysis results, in the general DEM ignoring visual obstacles of FIG. 9, the visible area is distributed very widely, whereas in the DEM reflecting the height of the building of FIG. 9, the visible area is relatively narrow and detailed. Therefore, more effective results can be obtained when selecting a viewpoint. This is likely to be useful in the field of work, such as reducing the burden on field surveys.

The best method for manufacturing DEM reflecting visual impairment is LiDAR (Light Detection and Ranging), which can acquire height data up to 10cm × 10cm resolution, but it is not suitable for generalization due to very high irradiation cost. Another method is to merge the building height value into a general DEM by using ZC0021 building structure and the number of floor cycle layers among 1/1000 digital map layers.

Since this method calculates the height by multiplying the number of floors of the building by the height of the floor (typically 3m), the method is used in the present invention because it is less accurate but suitable for obtaining data at low cost.

2. Post-processing of Analysis Results

Height-based data such as DEM and TIN do not allow visibility analysis that reflects vegetation. In general, the interpretation of the right view analysis considers the viewpoint and the viewing object in reverse, that is, the analysis considers the area visible from the viewpoint as the viewing object. Therefore, where vegetation, or a tree, is covered, an error occurs that is hidden from the tree and the view point at the time of interpretation is not visible.

In the present invention, a post-treatment method through vegetation index analysis was used to correct this. Vegetation index analysis is a measure of the vitality of plants. Normalized Difference (NDVI) is calculated by using band 4, which is the band 3 of the red band of 7 bands of Landsat-TM satellite image. Use the Vegetation Index a lot. Calculation of the regex index is the same as [Equation 3],

The result is a value between -1 and 1. In the absence of vegetation such as snow, clouds, soil, water, and artifacts, the value is close to -1, and the healthy and large vegetation region has a higher value than the non-vegetable region.

Figure 10 is a photograph showing the results of post-right analysis using the vegetation index for Daegu Innovation City using the embodiment according to the present invention. The site is a mountainous terrain that leads to Palgong Mountain to the north and shows high plant vitality. On the other hand, the general visibility analysis shows that the view target is visible even in mountainous terrain, which can confirm the error. If you look closely at (c) of FIG. 10, you can find a visible area and a low vegetation index like the area A. This area is used to estimate the accuracy of the analysis as it can overlook the Daegu area of Choebongbong Trail. can see.

3. Application Result of Visible Frequency Analysis

In the present invention, as a method of analyzing geographic information, conventional processes such as setting distance and direction criteria, viewing opportunities, and landscape beauty analysis after the visible frequency analysis process are omitted.

11 is a view showing a visible frequency analysis diagram of the world easy to Hyundae analysis method according to the present invention. As shown in FIG. 10, Daehyeon Ease World is located in Daehyeon-dong, Buk-gu, Daegu, and completed in 2008. It is an apartment complex of 527 households with a land area of 23379m2 and 527 households. The apartment is located directly on the side of Sincheon that crosses Daegu and is planned to be a 21-story high-rise apartment building.

Viewing points were divided into 30m × 30m grids and a total of 30 layers were selected as 8 layers and 240 layers were selected. The terrain data was preprocessed by constructing and adding the building height information to the general DEM constructed using the contours and elevations of the 1/1000 digital map. 11 is an analysis result, the upper eight photographs are visible frequency analysis for each layer, and the lower photograph is a visible frequency analysis combining them.

The visible region analysis (a) without the pretreatment of FIG. 12 analyzing the same region and the visibility analysis after the pretreatment (b) show very different results. It seems to be because it looks three-dimensional together.

Figure 13 is a photograph showing the visible frequency analysis of the Daegu Sinam redevelopment and maintenance district using an embodiment according to the invention. As shown in FIG. 13, the Daegu Sinam Redevelopment Promotion Zone was designated and announced in 2007, and is currently planning for 2017 with a total of 19000 households in an area of 1085498m2 as the target year.

Viewing points were divided into 100m × 100m grids and 83 points, excluding zones, were selected as one layer. The topographical data were analyzed in the same way as Daehyun's comfortable world. Although the site is a large area of more than 100 ha, it is not difficult to judge the magnitude of the visible frequency. This shows that it can be analyzed irrespective of the area of visible frequency analysis site.

14 is a photograph showing the visible frequency analysis of Daegu Innovation City using the embodiment according to the present invention. As shown in Fig. 14, Daegu Innovative City is a new town construction project with a total area of 4216496m2 as part of balanced development of the participatory government.

The site has regional characteristics, with mountainous topography to the north and existing urban areas to the south. Therefore, the analysis was performed in two forms, one of which was carried out post-processing on vegetation with a grid spacing of 200 m × 200 m at a resolution of 30 m DEM in order to analyze mountainous terrain in the north (see FIG. 14 (a)). The other was to analyze the grid distance of 100m × 100m at the viewing point in the DEM (resolution 3m) reflecting the height of the building to analyze the existing city in the south (see FIG. 14 (b)).

15 is a photograph showing the visible frequency analysis of the Gyeongju new history zone using an embodiment according to the present invention. As shown in FIG. 15, the Gyeongju New Area Tax Zone is under construction with the goal of constructing a complex new city of Gyeongju with the construction of the Gyeongju section of the high-speed railway in 2003. The Gyeongju new area has a branched location away from the city center, so it only used post-treatment using the vegetation index rather than pretreatment.

As shown in (c) of FIG. 15, the post-treatment by the vegetation index was effective in preserving the results of the visible frequency analysis of the mountainous regions by removing the areas not visible by the trees.

As such, the present invention focuses on the question of whether the analysis of visibility analyzed at a single viewing point can represent a wide range of targets, suggesting visibility analysis by multiple viewing points, and customizing the GIS program. By using this method, the following effects were obtained.

First, the visible frequency analysis is capable of stereo stereoscopic analysis by multiple points, and thus, the analysis results can be improved compared to the existing visibility analysis.

Second, the visible frequency analysis can be performed regardless of the size of the target site through the multi-layer grid point selection method.

Third, the visible frequency analysis can obtain more sophisticated results through the preprocessing process to prepare the DEM reflecting the height of the building for the treatment of visual obstacles or the post processing process using the regular vegetation index.

While the invention has been shown and described with respect to the specific embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Anyone with it will know easily.

Claims (13)

(a) selecting a viewing target point of the multilayer structure;
(b) calculating numerical data by viewshed analysis for each view target point;
(c) summing the numerical data calculated at the viewpoint targets of each floor to complete a visible frequency table; And
and (d) calculating a video image based on the visible frequency using the visible frequency table.
The method of claim 1,
Selecting the viewing target point in the step (a) is a grid point selection method of forming a multi-layer in a plurality of vertical directions, the geographic information analysis method using the visible frequency analysis, characterized in that for selecting the target point for each floor.
The method of claim 1,
The calculating of the digitized data of the step (b) is a geographic information analysis method using a visible frequency analysis, characterized in that using a digital elevation model (DEM).
The method of claim 1,
In step (c),
Creating a table by digitizing a visible region and an invisible region for each viewing target point of each layer by Vieshwed analysis; And
And summing the numerical tables of the respective layers to form a visible frequency table of the investigation target area.
delete delete (a) selecting a viewing target point of the multilayer structure;
(b) calculating numerical data by viewshed analysis for each view target point;
(c) summing the visible numerical values calculated at the viewpoint targets of the respective floors to complete a visible frequency table;
(d) post-processing using a normalized difference vegetation index (NDVI) result value in the visible frequency table; And
and (e) calculating a video image based on the visible frequency using the postprocessed visible frequency table.
The method of claim 7, wherein
Selecting the viewing target point in the step (a) is a grid point selection method of forming a multi-layer in a plurality of vertical directions, the geographic information analysis method using the visible frequency analysis, characterized in that for selecting the target point for each floor.
The method of claim 7, wherein
The calculating of the digitized data of the step (b) is a geographic information analysis method using a visible frequency analysis, characterized in that using a digital elevation model (DEM).
10. The method of claim 9,
The digital elevation model is a geographic information analysis method using the visible frequency analysis, characterized in that for calculating the pre-processed numerical value reflecting the height value of the artificial structure.
The method of claim 7, wherein
In step (c),
Creating a table by digitizing a visible region and an invisible region for each viewing target point of each layer by Vieshwed analysis; And
And summing the numerical tables of the respective layers to form a visible frequency table of the investigation target area.
delete delete

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