JP5566307B2 - Map data update device, map data update method, and map data update program - Google Patents

Description

  The present invention relates to a map data update device, a map data update method, and a map data update program.

  When updating map data including house position and shape information using spatial information obtained by aerial survey technology such as aerial photogrammetry and aerial laser measurement, high-resolution true ortho images and DSM (Digital Surface) are usually used. Model: numerical surface layer model) is acquired for the new and old two periods, and images and data of these two periods are compared to detect changes in the house during the two-period period.

  However, this method cannot detect a change in a house when spatial information in the old period is not available. In contrast to this, there is a method of performing change detection using existing house polygon data instead of the old space information. Specifically, conventionally, the house change is detected by comparing the outline of the house extracted from the true ortho image with respect to the new time and the house polygon of the old time. In this method, a change in house is detected based on edges, line segments, and contours extracted by two-dimensional image analysis using true ortho images.

JP 2004-117245 A Japanese Patent Laid-Open No. 2007-3244 International Publication No. 2009/051258 Pamphlet International Publication No. 2009/057619 Pamphlet

  In the method using house polygons for the old time, the extraction of edges, line segments, and contours based on the above-described two-dimensional image analysis for the new time is not accurate enough, and there is a problem that the false detection rate of house changes is high. . This problem becomes prominent in areas where houses are densely packed.

  The present invention has been made to solve the above problems, and an object thereof is to provide a map data update device, a map data update method, and a map data update program with improved detection accuracy.

  The map data update device according to the present invention performs the house change in the determination target area from the spatial information of the determination time including the numerical surface model acquired with respect to the determination target area and the house polygon of the time preceding the determination time. Detecting and updating the map data including the position and shape information of the house, extracting a convex part of the ground surface layer corresponding to the house from the numerical surface model, and in the determination target region based on the convex part Based on the absence of the house polygon corresponding to the house position, a new house detection means for detecting a new construction of the house at the house position, and the numerical surface model based on the numerical surface model Feature height extraction means for obtaining a feature height that is a height from the ground for an area corresponding to the house polygon, and the feature related to the house polygon Having a conventional house change detecting means for detecting a change of a house that is present in the house polygon based on.

  In the map data update device according to another aspect of the present invention, the existing house change detection means is based on the fact that the minimum value in the area corresponding to the house polygon of the feature height is less than the house height threshold. Then, the change of the house existing in the house polygon is detected.

  In the map data updating apparatus according to another aspect of the present invention, the feature height extracting means obtains the feature height for an internal region excluding an inner edge region arranged along the circumference from the house polygon.

  In the map data updating device according to another aspect of the present invention, the feature height extraction means is based on a minimum value of the height represented by the numerical surface layer model in an outer edge region arranged along the circumference of the house polygon. The height of the ground is determined, and the height of the feature is obtained using the height of the ground.

  In the map data updating apparatus according to another aspect of the present invention, the feature height extracting means forms a house polygon group in which the target house polygons for obtaining the height of the ground are linked by overlapping the outer edge region. If it is one of those to be performed, the minimum value within the entire outer edge region of the house polygon group is set as the height of the ground of the target house polygon.

  In the map data update device according to another aspect of the present invention, the spatial information includes an ortho image, and the house position determining means extracts a shape of a house area corresponding to the convex portion from the ortho image.

  In the map data update device according to another aspect of the present invention, based on the presence or absence of a non-overlapping portion between the house polygon corresponding to the house position determined by the house position determining means and the house region at the house position. And house area change detecting means for detecting a change of the house existing in the house polygon.

  According to the map data update method of the present invention, the house change in the determination target area is obtained from the spatial information of the determination time including the numerical surface model acquired for the determination target area and the house polygon of the time preceding the determination time. A method for detecting and updating map data including position and shape information of a house, wherein a convex portion of a ground surface layer corresponding to a house is extracted from the numerical surface layer model, and based on the convex portion, in the determination target region A house position determining step for obtaining a house position, a new house detection step for detecting a new house at the house position based on the absence of the house polygon corresponding to the house position, and the numerical surface model based on the numerical surface model A feature height extracting step for obtaining a feature height which is a height from the ground for an area corresponding to the house polygon; That having a conventional house change detection step of detecting a change of a house that is present in the house polygon based on the feature height.

  The map data update program according to the present invention causes a computer to acquire information on a determination target area from spatial information of a determination time including a numerical surface model and a house polygon at a time preceding the determination time, which is acquired regarding the determination target area. A program for functioning as a map data update device for detecting house changes and updating map data including the position and shape information of the house, and extracting convex portions of the ground surface layer corresponding to the house from the numerical surface model A house position determining means for obtaining a house position in the determination target area based on the convex part, and a new construction for detecting a new house at the house position based on the absence of the house polygon corresponding to the house position. Based on the house detection means and the numerical surface layer model, the area corresponding to the house polygon is at a height from the ground. That the feature height extracting means for obtaining the feature height, to realize the existing house change detecting means for detecting a change of a house that is present in the house polygon based on the feature high about the house polygon, to the computer.

  According to the present invention, in the change detection using the house polygon, the house object corresponding to the house is extracted based on the convex portion appearing in the DSM to detect the new house, while the feature height obtained from the DSM is detected. Based on this, a change in the existing house is detected, and the change detection accuracy is improved by a combination of these different detection methods. Further, by detecting the change of the existing house from the viewpoint of the change in the house height, it is possible to avoid the problem in the detection by the two-dimensional comparison with the house polygon.

1 is a schematic block diagram of a map data update device according to an embodiment of the present invention. It is a schematic diagram explaining the flow of the outline process of the map data update apparatus which concerns on embodiment of this invention. It is a schematic diagram explaining the ground height estimation processing of the feature height extraction unit. It is a schematic diagram explaining the ground height estimation process of the feature height extraction part in a densely populated house. It is a schematic diagram explaining the height acquisition process in the polygon of a feature height extraction part.

  Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 is a schematic block diagram of a map data update device 10 according to the embodiment. The map data update device 10 includes a processing unit 12, a display unit 14, a storage unit 16, and an operation unit 18, and detects a house change based on the spatial information acquired for the determination target region, Update map data including shape information.

  The processing unit 12 includes a house position determination unit 20, a new house detection unit 22, a feature height extraction unit 24, an existing house change detection unit 26, and a house region change detection unit 28. For example, the map data update device 10 can be configured using a computer, and its CPU constitutes the processing unit 12, a house position determination unit 20, a new house detection unit 22, a feature height extraction unit 24, an existing house The change detection unit 26 and the house area change detection unit 28 can be realized by a program executed by the CPU. In addition, the map data update apparatus 10 can also be set as the structure which abbreviate | omitted the house area | region change detection part 28. FIG.

  The storage unit 16 is a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), or a hard disk built in the computer. The storage unit 16 stores various programs and various data including processing programs of the house position determination unit 20, the new house detection unit 22, the feature height extraction unit 24, the existing house change detection unit 26, and the house region change detection unit 28. These pieces of information are input to and output from the processing unit 12. Further, the storage unit 16 stores various output files generated by the processing executed by the processing unit 12.

  The display unit 14 is an image display device such as a liquid crystal monitor, and the operation unit 18 includes a keyboard and a mouse.

  The map data update device 10 detects the change of the house in both periods from the spatial information of the judgment target area at the judgment time and the house polygon data of the judgment target area at the time preceding the judgment time. The map data update device 10 uses a true ortho image and a DSM as spatial information. The spatial information is generated from ground high-resolution image data such as aerial photographs and aerial laser measurement data. The map data update device 10 can be configured to perform processing for generating a true ortho image or DSM from observation data, or can be configured to input a true ortho image and DSM generated by processing the observation data in advance. You can also Spatial information is acquired by aerial measurement or the like performed at the determination time, but the house polygon data is existing data created in advance.

  The house position determination unit 20 extracts house objects corresponding to individual houses based on the spatial information of the determination target area. Specifically, the house position determination unit 20 defines a house object having information on the position and shape of the house existing in the determination target region at the determination time.

  The new house detection unit 22 checks whether a house polygon exists at the position (house position) of the house object existing at the determination time in the preceding time. When no house polygon exists at the house position, a new house is detected at the house position as a house transfer event.

  The feature height extraction unit 24 obtains the feature height that is the height from the ground for the region corresponding to the house polygon based on the DSM. The feature height extraction unit 24 performs processing for estimating the height of the ground for each house polygon and processing for acquiring the height in the house polygon, and calculates the height of the ground from the height in the house polygon. Subtract. Thereby, the height (feature height) of the feature existing in the house polygon at the determination time is obtained. The processing of the feature height extraction unit 24 will be described in more detail later.

  The existing house change detection unit 26 detects the change of the house existing in the house polygon in the preceding period based on the feature height obtained corresponding to the house polygon. For example, the height that a house would have is set as a threshold for the house height. For example, the threshold value of the house height can be about 2 to 3 m. In the preceding period when the house exists, the feature height in the house polygon is equal to or higher than the threshold of the house height. Therefore, if there is a portion where the feature height is less than the threshold value of the house height in the region corresponding to the house polygon at the determination time, the change in the house existing in the house polygon based on that is lost or Rebuilding can be detected. Specifically, the existing house change detection unit 26 is based on the fact that the minimum value in the region corresponding to the house polygon of the feature height obtained by the feature height extraction unit 24 is less than the house height threshold. Detect changes in houses.

  Based on the presence or absence of a non-overlapping portion between the area defined by the position and shape of the house object and the house polygon at the position corresponding to the house object, the house area change detection unit 28 detects the house existing in the house polygon. Detect changes.

  FIG. 2 is a schematic diagram for explaining a general processing flow of the map data update device 10. Based on the spatial information measurement data 40 stored in the storage unit 16, the house position determination unit 20 orthorectifies the aerial photographs and satellite images included therein to generate a true ortho image (S42). A DSM is generated based on the image data and the aviation laser measurement data included in the spatial information measurement data 40 (S42). The generated true ortho image and DSM are stored in the ortho image / DSM file 44 of the storage unit 16.

The house position determination unit 20 extracts the convex part of the ground surface layer corresponding to the house from the DSM stored in the ortho image / DSM file 44, and obtains the house position in the determination target region based on the convex part. The house position determination unit 20 extracts a shape of a house region corresponding to the true ortho-image image or al the convex portion stored in orthoimage · DSM file 44. The position (house position) and shape of these house areas are collectively referred to as “house object” (S46). The extracted house object is stored in the house object file 48. In addition, when the precision of DSM is sufficiently obtained, it is also possible to obtain a house object including a house shape using only the DSM.

  The new house detection unit 22 sequentially reads out the house positions from the house object file 48 and searches whether the house polygon data 50 exists in the house polygon data 50 at a position corresponding to the house position. If no house polygon exists at the house position, a new house construction at the house position is detected as a house change event, and the house change is recorded in the detection result file 54.

  The feature height extraction unit 24 uses the DSM stored in the ortho image / DSM file 44 for each house polygon stored in the house polygon data 50 to determine a reference for the height of the house at the position of the house polygon. The ground height Hg is estimated (S56). FIG. 3 is a schematic diagram illustrating the ground height estimation processing S56 of the feature height extraction unit 24. FIG. 3 shows a house polygon 100 that is an object for estimating the height of the ground. The feature height extraction unit 24 sets an outer peripheral buffer area (outer edge area) 102 along the circumference of the house polygon 100 in order to estimate the height of the ground in the area corresponding to the house polygon 100.

  The inner boundary of the outer periphery buffer area 102 coincides with the circumference of the house polygon 100, and the outer boundary is set at a position away from the circumference of the house polygon 100 by a predetermined distance. As a result, a belt-like outer peripheral buffer area 102 surrounding the house polygon 100 is set. The width of the band can be determined afterwards, for example, in accordance with the precision of the generated DSM so that, for example, the house change detection rate becomes the highest. On the other hand, since a position that is too far from the house polygon 100 may deviate from the height in the area corresponding to the house polygon 100, it is preferable to take this into consideration when setting the width of the outer peripheral buffer area 102. Specifically, if the position of the house polygon 100 is an area where an inclination is expected such as a mountainous area, it is possible to consider that the width is smaller than in the case of a flat ground. For example, the width of the outer peripheral buffer region 102 can be set to about 2 to 5 m, and this can be used as a threshold value.

  The feature height extraction unit 24 obtains a minimum value from the height data provided by the DSM in the outer periphery buffer area 102, and basically, the minimum value is used as the ground height Hg in the area corresponding to the house polygon 100. It is determined.

  On the other hand, the minimum value of the height in the outer periphery buffer area 102 may not be simply set as the ground height in the target house polygon 100. Specifically, this is a case where the target house polygon 100 exists in a densely populated house. FIG. 4 is a schematic diagram for explaining the ground height estimation processing S56 of the feature height extraction unit 24 in the densely populated house. FIG. 4 is a plan view showing a state in which another house polygon 104 exists near the target house polygon 100. In the figure, the outer boundary of the outer periphery buffer area 102 of the house polygon 100 is indicated by a dotted line, and the outer periphery buffer areas of other house polygons are not shown. For example, when the houses are close to each other and the outer peripheral buffer area 102 of the target house polygon 100 overlaps the adjacent house polygon 104, the height Hg of the ground cannot be obtained due to the precision of the generated DSM and the like. It can happen that the height at the house is at a minimum. Actually, the height change due to the DSM inside and outside the circumference of the house polygon becomes gentler than the actual height change of the house due to the precision of the generated DSM and the like, and as a result, the outer peripheral buffer area 102 Even if the adjacent house polygon 104 does not overlap, the above-described minimum value error may occur.

  Correspondingly, the feature height extracting unit 24, when the target house polygon 100 is one of the house polygon groups that are linked by overlapping the outer peripheral buffer area 102, the house polygon group The minimum value of the DSM height within the entire outer peripheral buffer area 102 is determined as the ground height Hg of the target house polygon 100. The house polygons constituting the house polygon group include a target house polygon P (0), a house polygon P (1) having an outer periphery buffer area overlapping with the outer periphery buffer area of the house polygon P (0), and a house polygon P (k ) A house polygon P (k + 1) having an outer peripheral buffer area overlapping with the outer peripheral buffer area (k is a natural number). In FIG. 4, the house polygon 100 is P (0), the house polygon 104 adjacent thereto is P (1), the house polygon 106 is P (2), and the ten house polygons 100, 104, 106 constitutes a house polygon group 110. When the feature height extraction unit 24 obtains the house polygon group 110, the feature height extraction unit 24 obtains the minimum value of the height of each of the house polygons constituting the house polygon group 102, and compares the minimum value for each house polygon. These minimum values are set as an estimated value Hg of the ground height in the area corresponding to the target house polygon 100.

  Note that the feature height extraction unit 24 may obtain the ground height Hg in the area corresponding to the house polygon 100 using the terrain data as external data. Alternatively, DSM (Digital Terrain Model) may be obtained by processing DSM, and the ground height Hg in the region corresponding to the house polygon 100 may be determined by the DTM.

  The feature height extraction unit 24 obtains the ground height Hg for each house polygon stored in the house polygon data 50 as described above, while using the DSM stored in the ortho image / DSM file 44, The representative value of elevation including the feature in the region corresponding to (the height in the polygon Hp) is acquired (S58). FIG. 5 is a schematic diagram for explaining the in-polygon height acquisition process S58 of the feature height extraction unit 24. FIG. 5 shows a house polygon 100 as an acquisition target area of the height within the polygon. The feature height extraction unit 24 obtains the height in the polygon based on the DSM in the internal region 122 excluding the belt-shaped inner peripheral buffer region (inner edge region) 120 arranged along the circumference from the house polygon 100. One reason for excluding the inner buffer area 120 is to avoid the influence of misalignment that may occur between the house polygon data and the DSM. Another reason is that, in the area where houses are dense as described above, there is a possibility that the difference between the actual height of the house and the height due to the DSM may increase due to the precision of the DSM generated near the boundary of the house, This is because the change detection accuracy is prevented from being lowered by excluding this portion as the inner peripheral buffer region 120.

  The outer boundary of the inner peripheral buffer area 120 coincides with the circumference of the house polygon 100, and the inner boundary is set at a position away from the circumference of the house polygon 100 by a predetermined distance. The width W of the inner peripheral buffer area 120 can be determined according to the precision of the generated DSM. The width W can be set to a fixed value common to each house polygon. The width W may be obtained by multiplying the size of the house polygon 100 by a proportional coefficient κ. Thereby, even when the house polygon 100 is small, the internal region 122 is secured. For example, the size of the house polygon 100 can be the dimension of the house polygon 100 in two directions orthogonal to each other, and the width W in each direction can be set by multiplying these dimensions by a proportional coefficient κ. Thereby, even when the house polygon 100 has, for example, an elongated shape, the internal region 122 is secured.

  The feature height extraction unit 24 obtains the minimum value of the DSM height in the internal region 122, and sets this as the in-polygon height Hp. Then, the height Hg of the ground is subtracted from the height Hp in the polygon, and the obtained value (Hp−Hg) is determined as the height of the feature existing in the house polygon 100 (feature height Ho) (S60). .

  The existing house change detection unit 26 compares the feature height Ho obtained in the feature height calculation process S60 with a threshold value of the house height. If Ho is less than the threshold value, it is considered that there is an area where no house exists in the internal area 122, and the existing house change detection unit 26 determines that a change event has occurred in the house existing in the house polygon 100 (S62). ). Specifically, such transfer events include the loss or rebuilding of a house. The existing house change detection unit 26 records the detected house change in the detection result file 64.

  The house area change detection unit 28 sequentially selects house polygons to be processed from the house polygon data 50, and reads out house objects having house positions corresponding to the house polygons from the house object file 48. Then, an area comparison process between the house polygon and the house object is performed (S66). In the area contrast processing S66, it is checked whether or not there is a non-overlapping portion between the house polygon and the house object area described above.

The presence or absence of a non-overlapping portion can be determined by comparing the ratio R of the area of the non-overlapping portion between the house polygon and the house object to the area of the house polygon (or house object) with a threshold value. For example, the area of the house object is So, the area of the house polygon is Sp, the area of the overlapping area between them is C, the non-overlapping area of the house object is Do (≡So-C), and the non-overlapping area of the house polygon is Dp ( If ≡Sp−C), the ratio Rp based on the house polygon and the ratio Ro based on the house object can be considered as the ratio R. The following formulas Rp = Dp / Sp, Ro = Do / So
Is calculated by

  The house area change detection unit 28 compares the ratios Rp and Ro with the threshold Th, and detects house change if, for example, Rp> Th or Ro> Th (S68). The house area change detection unit 28 records the detected house change in the detection result file 70.

  The threshold Th is set in consideration of the accuracy of the areas So and Sp. If the accuracy of these areas is sufficiently high, Th can basically be set to zero. However, in practice, the accuracy of determining the shape and area of the house object is not so high at present, and therefore Th greater than 0 is set in consideration of the trade-off between the accuracy and false detection and omission of detection.

  Further, when Rp ≦ Th, it is estimated that the entire house polygon is included in the house object, and when Ro ≦ Th, the entire house object is included in the house polygon. In the change detection process S68, for example, if Rp ≦ Th and Ro> Th, it can be determined that the house is to be rebuilt, and conversely if Ro ≦ Th and Rp> Th, it can be determined that the house is to be reduced.

  In the existing house change detection unit 26 described above, if the feature height Ho is equal to or greater than the threshold value of the house height, it is estimated that the house polygon 100 is present as a whole. In this case, the house polygon 100 in the preceding period is estimated. Since there is a possibility that the house that existed at the same time also exists at the determination time, the house change is not detected in the change detection process S62. However, in this case, there is a possibility that rebuilding has been done to expand the house. The house area change detection unit 28 can detect rebuilding that expands the house.

  The map data update device 10 integrates the detection result files 54, 64, and 70 output by the newly-built house detection unit 22, the existing house change detection unit 26, and the house region change detection unit 28, respectively, and changes the house as map data update information. Information is generated and output (S72). For example, the map data update device 10 outputs the house change information to the display unit 14.

  In addition, house transfers include expansion to increase the number of floors and reduction to reduce the number of floors. In the above-described embodiment, the house polygon data 50, which is two-dimensional information, is used as the information on the house at the preceding time. Therefore, the information that the house exists at the preceding time, that is, the height of the house is one story or more. Can only be given. For this reason, it is difficult to detect the extension or reduction of the number of floors. In this regard, for example, it may be configured to detect the extension / reduction using the number of floors of the house described in the building register as the information on the height of the house corresponding to the house polygon in the preceding period. Specifically, the number of floors of the house corresponding to each house polygon is stored as one of the attributes of the house polygon 100 of the house polygon data 50, for example, and the existing house change detection unit 26 stores the house with respect to the feature height Ho. The threshold value of the height is set to a different value according to the number of floors of the house, and the threshold value is determined.

  DESCRIPTION OF SYMBOLS 10 Map data update apparatus, 12 processing part, 14 display part, 16 memory | storage part, 18 operation part, 20 house position determination part, 22 newly-built house detection part, 24 feature height extraction part, 26 existing house change detection part, 28 house Area change detection unit, 40 Spatial information measurement data, 44 Ortho image / DSM file, 48 House object file, 50 House polygon data, 54, 64, 70 Detection result file, 100, 104, 106 House polygon, 102 Perimeter buffer area, 110 house polygon group, 120 inner buffer area, 122 inner area.

Claims (8)

The position and shape information of the house is obtained by detecting the house change in the judgment target area from the spatial information of the judgment time including the numerical surface layer model acquired for the judgment target area and the house polygon of the time preceding the judgment time. A map data update device for updating map data including:
Extracting the convex part of the ground surface layer according to the house from the numerical surface model, and the house position determining means for obtaining the house position in the determination target area based on the convex part,
Based on the absence of the house polygon corresponding to the house position, a new house detection means for detecting a new building of the house at the house position;
A feature height extracting means for obtaining a feature height that is a height from the ground for a region corresponding to the house polygon based on the numerical surface layer model;
An existing house change detecting means for detecting a change of a house existing in the house polygon based on the feature height related to the house polygon;
I have a,
The feature height extracting means obtains the feature height for an internal region excluding an inner edge region arranged along the circumference from the house polygon;
A map data update device characterized by the above. The map data update device according to claim 1,
The existing house change detecting means detects the change of the house existing in the house polygon based on the minimum value of the feature height in the region corresponding to the house polygon being less than the house height threshold. A map data update device characterized by that. In the map data update device according to claim 1 or 2 ,
The feature height extracting means determines the height of the ground based on a minimum value represented by the numerical surface layer model in an outer edge region arranged along the circumference of the house polygon, and determines the height of the ground. A map data update device characterized in that the feature height is obtained using a height. In the map data update device according to claim 3 ,
The feature height extracting means, when the target house polygon for obtaining the height of the ground is one of the house polygon groups linked by having an overlap in the outer edge region, The map data updating apparatus, wherein the minimum value in the entire outer edge region is set to the height of the ground of the target house polygon. In the map data update device according to any one of claims 1 to 4 ,
The spatial information includes an ortho image;
The house position determining means, in addition to the house position, extracting the shape of the house area corresponding to the convex portion from the ortho image;
A map data update device characterized by the above. In the map data update device according to claim 5 ,
Based on the presence / absence of a non-overlapping portion between the house polygon corresponding to the house position determined by the house position determination means and the house region at the house position, a change in the house existing in the house polygon is detected. A map data update device comprising house area change detection means. From the spatial information of the determination time including the numerical surface model acquired for the determination target region and the house polygon of the time preceding the determination time , the computer detects the house change in the determination target region, and the position of the house and A map data update method for updating map data including shape information,
Extracting the convex part of the ground surface layer according to the house from the numerical surface model, and the house position determining step for obtaining the house position in the determination target area based on the convex part,
A new house detection step of detecting a new construction of a house at the house position based on the absence of the house polygon corresponding to the house position;
A feature height extraction step for obtaining a feature height that is a height from the ground for an area corresponding to the house polygon based on the numerical surface layer model;
An existing house change detection step for detecting a change in a house existing in the house polygon based on the feature height related to the house polygon;
I have a,
The feature height extraction step is to obtain the feature height for an inner region excluding an inner edge region arranged along the circumference from the house polygon;
A method for updating map data. The computer detects the house change in the determination target region from the spatial information of the determination time including the numerical surface model acquired for the determination target region and the house polygon of the time preceding the determination time, and the position of the house and A program for functioning as a map data update device for updating map data including shape information,
Extracting the convex part of the ground surface layer according to the house from the numerical surface model, and the house position determining means for obtaining the house position in the determination target area based on the convex part,
Based on the absence of the house polygon corresponding to the house position, a new house detection means for detecting a new building of the house at the house position;
A feature height extracting means for obtaining a feature height that is a height from the ground for a region corresponding to the house polygon based on the numerical surface layer model;
An existing house change detecting means for detecting a change of a house existing in the house polygon based on the feature height related to the house polygon;
Is realized on a computer ,
The feature height extracting means obtains the feature height for an internal region excluding an inner edge region arranged along the circumference from the house polygon;
Map data update program characterized by

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