JP4165753B2 - Terrain deformation moving direction determination method and its determination system - Google Patents

Description

  The present invention relates to a terrain deformation movement direction determination method and its determination system for determining a terrain deformation movement direction such as a landslide movement direction.

  Sediment disasters occur throughout the country every year. In order to protect people's lives from such sediment disasters, the Sediment Disaster Prevention Law has been enacted. This law designates landslide disaster warning areas and landslide disaster warning areas. Sediment-related disaster warning area is an area where it is recognized that there is a risk of harm to the life or body of residents when a steep slope collapses.

  In order to prevent or reduce landslide disasters, it is necessary to establish a warning and evacuation system such as collecting and transmitting information on landslide disasters, issuing warnings, transmitting warnings, and condemning rescues in areas where landslide disasters may occur. There is. For this reason, in the municipal disaster prevention plan formulated by the municipal disaster prevention council, which is expected to play a central role in the alert and distress system related to sediment-related disasters, matters concerning the alert and evacuation system are defined for each alert area.

  In order to prevent human damage caused by landslide disasters, residents are informed of whether the land where their homes and facilities are located is in danger of landslide disasters and what kind of evacuation should be performed in an emergency. It is important that it is communicated correctly. For this reason, the mayor of the municipality is required for the transmission method of information on landslide disasters based on the characteristics of each area, the guidelines for evacuation areas when there is a risk of landslide disasters, and other smooth planned evacuation based on the municipal disaster prevention plan. We must endeavor to make the information known to the residents.

  The Sediment Disaster Special Warning Area is an area where there is a risk of serious harm to the lives or bodies of residents, etc. in the event of a collapse of a steep slope. Structural regulation is performed. In special caution areas, plans for countermeasure work to be carried out to prevent landslide disasters are being made for the development activities for the construction of facilities for vulnerable people such as residential housing lots, social welfare facilities, schools and medical facilities. Permitted only when the prefectural governor determines that it is in accordance with the technical standards necessary to ensure safety.

  In addition, in the earth and sand disaster special warning area, in order to prevent damage to buildings that may cause serious harm to the lives or bodies of residents, etc., against the force that debris etc. accompanying the collapse of steep slopes etc. exert on the building, In order to ensure that the structure of the building is safe, the building verification system is applied to buildings with living rooms.

  In other words, before starting construction of buildings in the area, submit an application to confirm whether the structure of the building meets the standards for preventing or reducing sediment-related disasters. It is necessary to receive confirmation from the director. In addition, recommendations and support measures such as building relocation are being taken in the Sediment Disaster Special Warning Area. In this way, various regulations have been made when designated as a landslide disaster special alert area.

  By the way, there are three main types of landslide disasters: (1) collapse of steep slope (crash), (2) debris flow, and (3) landslide. Among these, for example, with respect to landslides, the determination of the land with the possibility of disaster will be described with reference to the schematic diagram of FIG. In FIG. 15, 1 is a landslide block, 2 is a sliding cliff, 20 is a contour line, and B is a moving direction of the landslide. D is the midpoint of the line segment connecting the intersection of the landslide block boundary 1a and the contour line 20.

  (P) is a landslide area or an area where there is a risk of landslide, (Q) is an area of land where there is a risk of significant harm, (R) is a land where there is a risk of harm due to landslide below the landslide area Shows the area. L1 is the length of the landslide area, and L2 is the length of the land that may be harmed by the landslide below the landslide area, and is set equal to L1. L3 is the length of land that may be seriously harmed, and L4 is a length that spans the areas (P) and (R), and is set to a maximum of 250 m. L5 is the length of the land that may be harmed by landslides. W1 indicates the width of the landslide area.

  Next, rank classification for landslide will be described. Based on past data (disaster history, survey / observation / design / construction-related materials), aerial photo interpretation results, 3D map extraction results, and field survey results, the landslide block is clear and slidable. , B, C. The definition of each rank is set as follows.

  (1) Rank A, which can confirm that the landslide is sliding, and can determine the outline and the end of the entire landslide block. (2) Rank B, which cannot confirm that the landslide is sliding, but can determine the outline and the decline of the entire landslide block. In addition, it can be confirmed locally that the landslide is sliding, but the outline and the end of the landslide block cannot be determined. (3) Rank C, the landslide is not sliding, and the entire landslide block contour and end cannot be determined.

  Next, explanation will be given on the area setting conditions of the land where there is a risk of harm. (1) Landslide area. It is a landslide area or an area that may be landslide. In addition to landslide blocks + sliding cliffs, if there are cracks or step topography that are considered signs of landslides outside the sliding cliffs, the area should be included in the landslide area.

  (2) The area within the distance corresponding to the length of the landslide mass from the lower end of the landslide area, and if the length of the landslide mass exceeds 250 m, it shall be from the lower end of the landslide area to 250 m. However, this excludes areas of land where it is clearly not possible for debris to reach the topography.

  When a landslide occurs, as mentioned above, there is a possibility that it will be designated as a landslide disaster special warning area, and the property rights of residents will be regulated. For this reason, it is important to detect landslides. In order to respond to such a request, Patent Documents 1 and 2 describe techniques for detecting landslides.

  In Patent Document 1, an optical fiber cable is attached to a part for measuring deformation such as a bedrock and a slope, and an optical pulse tester is connected to one end of the optical fiber cable to measure a longitudinal strain generated in the optical fiber cable. Then, it is described that deformation measurements of rocks, slopes, etc. are performed. Moreover, in patent document 2, the upper part of a main wire is fixed to the upper part of the ground where there is a risk of landslide, and a weight is attached to the lower part of the main wire to give a tensile force. A stopper is fixed in the middle of the main wire, and the detector is supported by the stopper. Landslide is detected by this detector.

  However, with the techniques described in Patent Document 1 and Patent Document 2, only landslides in a narrow area can be detected, and if a landslide is to be detected in a wide range, a large number of detection means must be installed, which increases the cost. There was a problem. In addition, in order to designate the landslide disaster special warning area, it is necessary to determine the moving direction of the landslide in a certain area. In the techniques described in Patent Document 1 and Patent Document 2, such a certain landslide disaster warning area is required. There was a problem that the direction of landslide movement in this area could not be determined.

JP-A-10-197298 Japanese Patent Laid-Open No. 11-241930

  Therefore, in order to determine the direction of movement of a landslide that occurs in a certain area, conventionally, analysis using aerial photographs has been performed. The landslide topography is the result of the movement of the landslide mass, and the shape of the contour lines is characteristic. The shape and movement direction of the landslide block estimated by the terrain engineer based on the interpretation of the aerial photograph are entered directly on the photograph. At this time, the moving direction of the landslide is set to a direction orthogonal to the contour line with reference to the direction that can be read by aerial photo interpretation.

  In the above two processes, landslides occur when “the aerial photograph is interpreted and the shape and direction of movement of the landslide block are entered on the photograph” and when “the shape and direction of movement of the landslide block are transferred in line with the contour line”. There are differences in the shape and direction of readers. In this way, depending on the subjectivity of the terrain engineer (reader), the results of aerial photo interpretation in the same area tend to differ. The survey results on the shape and direction of the landslide block limit private rights, so the objective and uniformity of the survey results are required, but there is a problem that such requests cannot be met.

  This invention solves the said subject, and aims at provision of the terrain deformation moving direction determination method and its determination system which objectively determine the moving direction from terrain shape about terrain deformation like a landslide. .

  To that end, the terrain deformation movement direction determination method of the present invention includes a step of selecting a survey target location of the topographic deformation, a step of taking an aerial photograph of the survey target location, and creating a topographic map in which contour lines are entered from the aerial photo Analyzing the topographic map, extracting the topographic deformation block, creating a plurality of line segments connecting the boundary of the topographic deformation block and the contour line, and setting the midpoint of each line segment And determining the terrain deformation moving direction by selecting two points from the plurality of midpoints and creating a line segment connecting the two selected midpoints. In this way, the midpoint is set on the line segment connecting the boundary between the contour line and the topographic deformation block, and these midpoints can be set objectively without depending on the subjectivity of the reader. The terrain deformation movement direction is determined from the line segment connecting the midpoints of the two points. For this reason, the terrain deformation movement direction can be objectively determined without causing a difference depending on the reader.

  The present invention also includes a step of selecting a survey target location for topographic deformation, a step of taking an aerial photograph of the survey target location, a step of creating a topographic map in which contour lines are entered from the aerial photo, and the topographic map. Extracting a terrain deformation block, creating a plurality of line segments connecting the boundary of the terrain deformation block and the contour line, setting a perpendicular bisector perpendicular to each line segment, and The terrain deformation moving direction is determined by determining the average of the directions of the perpendicular bisectors orthogonal to the line segments. As described above, the vertical bisector is set on the line segment that connects the boundary between the contour line and the terrain deformation block, and the vertical bisector can be set objectively without depending on the subjectivity of the reader. The terrain deformation moving direction is determined from the direction of the perpendicular bisector (average angle). For this reason, the terrain deformation movement direction can be objectively determined without causing a difference depending on the reader.

  The present invention is characterized in that the topographic deformation is a landslide. Thus, since the landslide movement direction is objectively determined, property rights such as evacuation of residents and building restrictions on houses can be quickly executed.

  Further, the present invention is characterized in that the length of the landslide block is set from a horizontal distance between an upper end and a lower end of the landslide block in a direction parallel to the moving direction of the landslide. Thus, since the length of a landslide can be set, the range of the length direction of a landslide can be specified.

  Further, the present invention is characterized in that the width of the landslide block is set from a horizontal distance between the left end and the right end of the landslide block in a direction orthogonal to the moving direction of the landslide. Thus, since the width of a landslide can be set, the range of the width direction of a landslide can be specified.

  Further, the present invention is characterized in that a landslide end position is specified from a terrain change point or a terrain deformation trace of the landslide end portion. In this way, since the end position of the landslide is specified, it is possible to take measures in advance for the influence on the life, safety, and property such as buildings of the residents.

  In addition, the present invention is characterized in that the landslide rank classification is set based on the clarity and slidability of the landslide block. Therefore, it is possible to objectively determine the degree of landslide risk.

  The terrain deformation movement direction determination system according to the present invention includes a map reading means in which a terrain deformation block is extracted from a topographic map in which contour lines are entered from an aerial photograph, a storage means for the read map data, and a read from the storage means. Means for acquiring intersections between boundaries of the topographic deformation blocks and the contour lines of the generated map data; means for creating a plurality of line segments connecting the intersections; and means for setting the midpoints of the line segments; And a means for selecting two points from the plurality of midpoints, and a means for determining a terrain deformation moving direction by a line segment connecting the two selected midpoints. For this reason, the terrain deformation movement direction can be determined automatically and accurately based on the map from which the terrain deformation block is extracted.

  The terrain deformation movement direction determination system according to the present invention includes a map reading means in which a terrain deformation block is extracted from a topographic map in which contour lines are entered from an aerial photograph, a storage means for the read map data, and a read from the storage means. Means for acquiring intersections between boundaries of the topographic deformation blocks of the map data and the contour lines, means for creating a plurality of line segments connecting the intersections, and a perpendicular bisector perpendicular to each line segment. It is characterized by comprising means for creating and means for obtaining an average of the directions of the perpendicular bisectors orthogonal to the respective line segments. For this reason, it is possible to automatically execute a complicated process of creating a perpendicular bisector perpendicular to each line segment, and to accurately determine the terrain deformation moving direction.

  The present invention is characterized in that the topographic deformation is a landslide. For this reason, the landslide movement direction can be determined quickly.

  Further, the present invention is characterized by comprising output means for outputting the determined landslide movement direction data. For this reason, the landslide movement direction can be clearly recognized.

  According to the method of the present invention, it is possible to objectively determine the terrain deformation moving direction such as landslide. In addition, according to the system of the present invention, it is possible to accurately and quickly determine the terrain deformation moving direction.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 is a flowchart showing a procedure for creating a topographic map using an aerial photograph used in the present invention. In FIG. 7, the topographic map creation process is started (step S1). Next, an anti-air sign is installed at the photographing location (step S2). In this process, a mark that can be recognized by a photograph is placed at a location where the coordinates (X, Y, H) are known at the shooting site.

  Subsequently, photography is mainly performed by an aircraft (step S3). Next, leveling is performed (step S4). In this process, the height of the feature (white line corner, road curb corner, etc.) shown in the photograph is obtained in order to obtain the inclination of the photograph at the moment of photographing. Next, a field survey is performed (step S5). The field survey is to investigate things that cannot be seen in the photographed photos, referring to the photos.

  Subsequently, aerial triangulation is performed (step S6). In this process, a photograph is taken by being divided into several sheets, and the photograph is taken with various inclinations depending on the attitude of the aircraft at the time of photographing. These are calculated so as to become one photograph in the computer. Next, a numerical plotting process is performed (step S7). In this process, the terrain is taken out as three-dimensional coordinates based on the body of the photograph, and the features and the terrain represented by the map are drawn.

  Thereafter, numerical editing is performed (step S8). This processing is to convert the map symbols determined according to the purpose for easy viewing as a drawing. Next, a supplementary survey is performed (step S9). In this process, when there is a problem that cannot be solved in the process so far, the investigation and the field survey are performed again at the site. Output such as print output is performed (step S10), and a series of processing ends (step S11).

  FIG. 8 is a flowchart showing a procedure for investigating a land where there is a risk of harm, and FIG. 9 is an explanatory diagram of output materials at each stage in the flowchart of FIG. For conversion reasons, the numbers with circles are replaced with numbers with parentheses. Further, (a) to (g) in FIG. 8 correspond to (a) to (g) in FIG. 9, respectively.

  (1) Extraction of survey target locations. Data collection starts (Aa). Study the target area from the topographic conditions (Ab) and the target area from the social conditions (Ac). Based on this result, an investigation target site examination diagram (for example, 1 / 25,000) is prepared (a). Next, the investigation target part is extracted (Ad). Based on this result, a list of locations to be investigated is created (b).

  (2) Survey for area setting. In this process, analysis of existing survey data (Ba), interpretation of aerial photographs (Bb), arrangement of 3D terrain model maps, and terrain analysis (Bc) are performed. The processes (Bb) and (Bc) are particularly important. And is surrounded by a black frame and displayed as (Bx). In this process, an aerial photograph interpretation map, an inclined section map, etc. are created (c).

  Next, a field survey landslide map is created (Bd). Here, for example, an area study map enlarged to 1/2, 500 is prepared (d). Next, a field survey is conducted (By). In the field survey, topographic survey (Be) such as variable topography, geology (Bf) such as the name of geology, and countermeasure facilities (Bg) such as the type of facility are targeted. A field survey summary table is prepared after the field survey (e).

  (3) Setting of potentially dangerous land. In this process, an area is set (Ca). Based on this result, a 1/2, 500 zone setting draft is created (f). (4) Survey of potentially harmful land. In this process, surveys are made on land use status, the number of households, the number of people, public facilities, warning evacuation, related laws and regulations, and land development (Da). The output materials based on these results are area setting records, residential land development, and construction trend survey tables (g). As a summary of the above processing, an area setting record is created (Ea).

  FIG. 10 is a flowchart showing a procedure for setting an area for a land that may be harmful. Next, this flowchart will be described. Study areas that may be landslide (F). Subsequently, the landslide movement direction is set (G). The setting of the moving direction is a feature of the present invention as described later, and is surrounded by a black frame. Next, the length and width of the landslide are set (H). Also, landslide rank classification is performed (I). Finally, the area of the land where there is a risk of harm is set.

  The direction of landslide movement is set by the following method. (1) Setting the direction of travel based on past data (survey / observation report, disaster history). (2) Setting of moving direction examined by 3D map. (3) Setting of moving direction by aerial photo interpretation. (4) Setting the direction of travel based on field surveys. Among these, when the landslide movement direction is indicated by the past trade charges, that direction has the highest priority. If there is no previous data, the direction based on the aerial photo interpretation and 3D map is used as a reference, and in principle, multiple engineers set the direction of movement based on the field survey results.

  Here, the setting of the landslide movement direction by the three-dimensional map will be described. The direction of landslide movement shall be the direction of movement when there is dynamic observation data such as borehole inclinometers or fixed point surveys, or when the direction of movement is specified in past data. For those for which there are no historical data or dynamic observation data, the decision is usually made based on the judgment of a professional engineer in the interpretation of aerial photographs and field surveys. However, in the area setting process, the direction of landslide movement has an important meaning and needs to be explained to the residents. Therefore, it is necessary to determine the direction of movement in an objective and reproducible manner.

  Depending on the type of landslide, the movement form of the lump and the difference in the shape of the slip surface are predicted, so the direction of landslide movement will be examined with reference to the results of topographic interpretation and field surveys. In addition, when there is a composite block described later, the outer shape of the landslide block and the slope of the inner slope are often greatly disturbed, and it may be very difficult to examine the direction of the landslide. In particular, dynamic observation may not be effective for landslides that are not active. In this case, examine the direction of landslide movement by using multiple methods such as this study method (midpoint method, orthogonal line method) and aerial photo interpretation.

  FIG. 11 is a flowchart showing a processing procedure when setting the landslide movement direction. Next, this flowchart will be described. Output of confirmed movement direction of landslide by past survey and observation (a), Output of estimated movement direction of landslide by memory survey (b), Output of estimated movement direction of landslide by aerial photo interpretation (c), Landslide by three-dimensional map The output (d) of the estimated movement direction is performed. After the output of the estimated movement direction of the landslide by the interpretation of the aerial photograph in (c), it is determined whether or not there is a comprehensive judgment by a professional engineer (e). When the determination result is YES, the desktop survey arrangement table is printed out (i).

  When the determination result of (e) is NO, a loop process for determining the estimated movement direction of landslide by field survey is performed with reference to the outputs of (b) and (d) (f). Next, the presence / absence of comprehensive judgment by a professional engineer is determined (g). If this determination is YES, the field survey summary table is printed out (j). When the determination result of (g) is NO, the landslide moving direction is set with reference to the output of (a) (h).

  The landslide movement direction is basically set in a direction orthogonal to the contour line. A contour line means a line connecting points having the same altitude. Further, the direction orthogonal to the contour line is the steepest slope at that point. However, since the Isotei line has various shapes for each point, the steepest slope is determined by looking over the entire block. At this time, if the average of the directions orthogonal to the contour lines included in the landslide block is obtained, the direction of the landslide block can be obtained.

  The present invention is characterized in how to obtain an average in a direction perpendicular to the contour line. FIG. 2 is a topographic map for explaining the present invention. In FIG. 2, reference numeral 1 denotes a landslide block whose contour lines are disturbed. Reference numeral 4 denotes a normal area in which contour lines are arranged at almost equal intervals.

  FIG. 1 is an explanatory diagram of the landslide block 1 of FIG. In FIG. 1A, 1 is a landslide block, 2 is a sliding cliff, 3 is a landslide area, 20 is a contour line, and B is a moving direction of landslide by photo interpretation. D is the midpoint of the line segment connecting the intersection of the landslide block boundary 1a and the contour line 20. In the present invention, the moving direction of the landslide is set by the midpoint method of FIG. 5B and the orthogonal method of FIG.

  The midpoint method in FIG. 1B is based on a line connecting two points Dr and Dx from the midpoint D of the line segment connecting the contour line 20 and the boundary 1a of the landslide block. To decide. When selecting the two points Dr and Dx, pay attention to the shape of the landslide block 1 and the disturbance of the contour line 20. Considering the cross-sectional view, it is generally considered that the deepest point of the sliding surface passes through the center of the landslide block 1, and therefore the moving direction of the landslide is determined by a line connecting the midpoints.

  In the orthogonal line method of FIG. 1 (c), vertical bisectors V orthogonal to the line segment connecting the contour line 20 and the boundary 1a of the landslide block 1 are drawn, and the average direction of the vertical bisectors V (average) The movement direction Xb is determined with reference to the direction obtained by calculating (angle). Since landslides can be interpreted from the terrain situation, the influence of sliding is considered to be reflected in the terrain when viewed globally, so the direction of landslide movement is determined by averaging the maximum slope direction.

  Thus, in either case of the midpoint method of FIG. 1B or the orthogonal line method of FIG. 1C, the midpoint or orthogonality on the line segment connecting the contour line 20 and the boundary 1a of the landslide block 1 Vertical bisectors are created, and these midpoints or vertical bisectors can be set objectively regardless of the reader's subjectivity. The landslide movement direction is determined from the average direction (average angle) of the line connecting the midpoints of the two points or the perpendicular bisector. For this reason, the landslide movement direction can be objectively determined without causing a difference depending on the reader.

  FIG. 3 is an explanatory diagram showing a basic principle for selecting a landslide block when determining a landslide movement direction according to the present invention. FIG. 3A shows a normal area 4 where the contour lines 20 are aligned as shown in the topographic map of FIG. 2 and a landslide block 1 where the contour lines 20 are disturbed. Ra is a cross-sectional line of the normal area 4, and Rb is a cross-sectional line of the landslide block 1.

  FIG. 3B is a side view of the normal area 4 as viewed in the direction of the cross-sectional line Ra, and the ground surface 5 has no inflection point and is continuous. FIG. 3C is a side view of the landslide block 1 as viewed in the direction of the cross-sectional line Rb. The ground surface 5a has an inflection point 5x and has a distorted shape. That is, the portion 6 cut by the landslide moves in the Z direction and forms the embankment 7. Thus, in the present invention, the landslide block is specified by paying attention to whether the contour line normally appears in the topographic map or the contour line is disturbed.

  Next, the setting of the length and width of the landslide will be described. 4 (a) and 4 (b) are explanatory diagrams of an example in which the length of landslide is set. The length of the landslide is a horizontal distance between the upper end and the lower end of the landslide block in a direction parallel to the moving direction of the landslide. The top edge of the landslide block shall be the outer periphery of the sliding cliff. 4A and 4B, Xc is the landslide movement direction, La and Ld are horizontal distances of the landslide area, Lb and Le are horizontal distances of the sliding cliffs, and Lc and Lf are the lengths of the landslide blocks. In the example of FIG. 4, since the length of the landslide is set, the range in the length direction of the landslide can be specified.

  FIGS. 5A and 5B are explanatory diagrams of an example in which the width of the landslide is set. The width of the landslide is a horizontal distance between the left end and the right end of the landslide block in a direction orthogonal to the landslide moving direction. In FIG. 5B, Wc is the width of the soil block, and Wb is the width of the landslide block. In FIG. 5A, the width of the soil block and the width of the landslide block are both Wa. In the example of FIG. 5B, the width of the sliding cliff is larger than the width of the soil block.

  In general, as shown in FIG. 5 (a), in the case of the width of the soil block ≧ the width of the landslide block, the width of the landslide block is set to the width of the soil block. Further, as shown in FIG. 5B, in the case of the mass width <the width of the sliding cliff, the width of the landslide block is set to the width of the sliding cliff. Thus, since the width of the landslide block is set in the example of FIG. 5, the range in the width direction of the landslide can be specified.

  Next, the setting of the landslide block end position will be described. In general, it is difficult to determine the end portion of the landslide block from the head, and in the Sediment Disaster Prevention Law, the position of the end portion greatly affects the setting of “land with danger”. Therefore, the landslide block end position needs to be set with particular care. The landslide block end position is set by the following (1) to (3).

  (1) When the terminal position is specified by a past survey. If the survey results are confirmed or estimated based on borehole survey results (score observation results, slip surface survey results from borehole inclinometers, etc.), the end position of the landslide is identified from the past survey results.

  (2) When there is a clear deformation due to a landslide (a trace of deformation) at the end. If there is a recent history of sliding or if there are obvious deformations such as uplift or push-out due to active landslides, the end position of the landslide is identified on site.

  (3) The terminal position is not specified in the past survey data, and no deformation is observed. Estimate the end position of the landslide with reference to the following matters. a) Transition lines near the landslide end and topographic change points at the end. b) Terrain deformation traces such as bumps, compression crack traces, and extrusion traces. In many landslide areas, there is no previous survey result and there is no clear trace of deformation at the end, so the estimation by (3) is applied.

  FIG. 6 is an explanatory diagram illustrating an example of the end position of the landslide. In FIG. 6, the landslide block 1 shows a landslide end line 8 along with a sliding cliff 2, a small collapse 9, and a gentle slope 10. As described above, specifying the end position of the landslide has a great influence on the setting of “land with danger”. In the example of FIG. 6, the end line 8 of the landslide is set by the method described in the above (3).

  FIG. 12 is a block diagram showing the system configuration of the present invention. In FIG. 12, reference numeral 30 denotes a component of the system, which includes an arithmetic processing unit 31 that uses a CPU, an input unit 32 such as a keyboard and a mouse, a reading unit 33, a display unit 34, a storage unit 35, and prints data and graphics. An output unit 36 is provided. The storage unit 35 is provided with a ROM storing processing programs, a RAM storing various data, an image memory storing image data, and the like. The three-dimensional map data (digital mapping) created by the plotter 40 is input to the arithmetic processing unit 31 as necessary.

  The topographic map in which the aerial photograph 41 is subjected to predetermined processing by the plotter 40 and the landslide block is read is input as a reference map 50 from the reading unit 33 to the arithmetic processing unit 31. Here, the processing of the plotter 40 will be described. The mapper 40 is a device for acquiring map data from an aerial photograph as described in FIG. The plotter is an apparatus that creates a stereoscopic image in which a pair of aerial photographic films photographed in duplicate are placed on a photographic stand and are individually observed with the left and right eyes through eyepieces.

  In order to perform the plotting process, aerial triangulation is performed in which an anti-air sign is placed on the aerial photograph so that the ground reference point can be seen and a reference point is added to each model. When creating a topographical map in which contour lines are written from the aerial photograph 41, data of intervals is created by moving the aerial photograph while tracing it with the observation target of the plotter 40. The creation of topographic maps in which contour lines are entered from aerial photographs using a mapper is used as a standardized data format defined by the Geographical Survey Institute.

  The reference map input from the reading unit 33 to the arithmetic processing unit 31 is subjected to predetermined processing such as binarization and is stored in the storage unit 35 as image data. When the processing program is activated, the arithmetic processing unit 31 reads the image data stored in the storage unit 35 and executes an algorithm for determining the landslide movement direction.

  FIG. 13 is an explanatory diagram showing a processing flow when the landslide movement direction by the midpoint method is determined by the system 30 of FIG. FIG. 13A shows image data of a topographic map from which the landslide block 3 has been read, and is read from the storage unit. In (a), 1a is a boundary of a landslide block, and 20 is a contour line. In (b), the contour line 20a that intersects the boundary of the landslide block 3 is selected, and its intersection points Ga and Gb are acquired.

  In (c), the points acquired as the intersection of the boundary of the landslide block 3 and the contour line 20a are connected by the straight line Kp, and the midpoint Dp of the straight line Kp is acquired. (D) Processes (b) to (c) are executed in the entire area of the landslide block 3. By this process, straight lines Kp to Ky and midpoints Dp to Dy are obtained. In (e), two points Dp and Dx for determining the moving direction of the landslide block are selected from the acquired middle points Dp to Dy. The direction in which the two points Dp and Dx are connected is defined as the movement direction Xa of the landslide block. These processes (a) to (e) are executed by image processing by the arithmetic processing unit 31.

  FIG. 14 is an explanatory diagram showing a processing flow for determining the landslide movement direction by the orthogonal line method. FIG. 14A is image data of a topographic map from which the landslide block 3 has been read, and is read from the storage unit. 1a is a boundary of a landslide block, and 20 is a contour line. In (b), the contour line 20a that intersects the boundary of the landslide block 3 is selected, and its intersection points Ga and Gb are acquired.

  The points acquired by the process of (c) are connected by a straight line Kp, and the perpendicular bisector Vp is created. The processes (b) to (c) are performed in the entire area of the landslide block by the process (d). By this process, straight lines Kp to Ky and vertical bisectors Vp to Vy are obtained. In (e), the average of the directions of the obtained vertical bisectors is defined as the movement direction Xb of the landslide block. These processes (a) to (e) are also executed by image processing by the arithmetic processing unit 31.

  The system of the present invention shown in FIGS. 13 and 14 can automatically and accurately determine the landslide movement direction based on the map from which the landslide blocks are extracted. Moreover, the landslide movement direction can be clearly determined by printing out the data related to the landslide movement direction from the output unit 36 of FIG.

  In the present invention, the range of the landslide length and width is specified, and the tip position of the landslide is set. As described above, the landslide slidability is clarified together with clarifying the range of the landslide block, so that the ranking of the landslide can be performed. In this way, by setting the rank classification for landslide by the method of the present invention, the area setting of the land that may be harmful can be made based on the objective criteria, and the reliability can be improved.

  The above description is directed to a method and system for determining a landslide movement direction, but the present invention is not limited to landslides, and can be applied to determining a general terrain deformation movement direction associated with, for example, uplift or depression. it can.

  As described above, according to the present invention, it is possible to provide a terrain deformation movement direction determination method and a determination system for objectively determining the movement direction of terrain deformation such as landslide from the terrain shape.

It is explanatory drawing of the landslide block by this invention. It is a topographic map for demonstrating this invention. It is explanatory drawing which shows the basic principle of the landslide movement direction setting of this invention. It is explanatory drawing which shows the example of the length setting of a landslide. It is explanatory drawing which shows the example of the width setting of a landslide It is explanatory drawing which shows the example of a setting of the terminal position of a landslide. It is a flowchart which shows the procedure of topographic map creation by an aerial photograph. It is a flowchart which shows the investigation procedure of the land etc. which might be harmful. It is explanatory drawing of the output material of FIG. It is a flowchart which shows the process sequence of area setting. It is a flowchart which shows the process sequence at the time of setting the movement direction of a landslide. 1 is a block diagram showing a system configuration according to an embodiment of the present invention. It is explanatory drawing of the algorithm concerning this invention. It is explanatory drawing of the algorithm concerning this invention. It is a schematic diagram which shows the setting of the land with a possibility of a disaster.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Landslide block, 2 ... Sliding cliff, 3 ... Landslide area, 4 ... Normal area, 5 ... Ground surface, 6 ... Sliding part, 7 ... Filling part, 8. .. End line, 9 ... small collapse, 10 ... gentle slope, 20 ... contour, 30 ... system component 31 ... arithmetic processing unit, 32 ... input unit, 33 ... ..Reading unit, 34 ... display unit, 35 ... storage unit, 36 ... output unit, 40 ... drawing machine

Claims (11)

Selecting a survey target location for topographic deformation, taking an aerial photograph of the survey target location, creating a topographic map with contour lines drawn from the aerial photo, analyzing the topographic map, and converting a topographic deformation block Extracting a point, creating a plurality of line segments that connect the boundary of the topographic deformation block and the contour line, setting a midpoint of each line segment, and selecting two points from the plurality of midpoints A method of determining a terrain deformation movement direction, comprising: determining a terrain deformation movement direction by a step and a step of creating a line segment connecting the two selected midpoints. Selecting a survey target location for topographic deformation, taking an aerial photograph of the survey target location, creating a topographic map with contour lines drawn from the aerial photo, analyzing the topographic map, and converting a topographic deformation block Extracting a plurality of line segments connecting boundaries of the topographic deformation blocks and the contour lines, setting vertical lines orthogonal to the line segments, and extracting vertical lines orthogonal to the line segments. A method for determining a terrain deformation movement direction, comprising: determining a terrain deformation movement direction according to a step of obtaining an average of directions. The terrain deformation movement direction determination method according to claim 1, wherein the terrain deformation is a landslide. The terrain deformation movement direction determination method according to claim 3, wherein a length of the landslide block is set from a horizontal distance between an upper end and a lower end of the landslide block in a direction parallel to the movement direction of the landslide. . The terrain deformation movement direction determination method according to claim 3, wherein a width of the landslide block is set from a horizontal distance between a left end and a right end of the landslide block in a direction orthogonal to the landslide movement direction. The terrain deformation movement direction determination method according to any one of claims 3 to 5, wherein a landslide end position is specified from a terrain change point and a terrain deformation trace of the landslide end part. The terrain deformation movement direction determination method according to any one of claims 3 to 6, wherein the landslide rank classification is set based on the clarity and slidability of the landslide block. A map reading means in which a terrain deformation block is extracted from a topographic map in which contour lines are entered from an aerial photograph, a storage means for the read map data, and the terrain deformation block of the map data read from the storage means A means for acquiring an intersection between a boundary and the contour line; a means for creating a plurality of line segments connecting the intersection points; a means for setting a midpoint of each line segment; and selecting two points from the plurality of midpoints A terrain deformation movement direction determining system comprising: means; and a means for determining a terrain deformation movement direction by a line segment connecting the two selected middle points. A map reading means in which a terrain deformation block is extracted from a topographic map in which contour lines are entered from an aerial photograph, a storage means for the read map data, and the terrain deformation block of the map data read from the storage means Means for obtaining an intersection between a boundary and the contour line, means for creating a plurality of line segments connecting the intersection points, means for creating a perpendicular bisector perpendicular to each line segment, and orthogonal to each line segment A terrain deformation moving direction determination system comprising: means for calculating an average of directions of vertical bisectors. The terrain deformation movement direction determination system according to claim 8 or 9, wherein the terrain deformation is a landslide. The terrain deformation movement direction determination system according to claim 10, further comprising output means for outputting the determined landslide movement direction data.

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