JP2008310036A - Inundation depth surveying system and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To estimate, from the inundation depth at a plurality of points obtained through on-site investigation of a flood, the distribution of inundation depth in a flooded area. <P>SOLUTION: A program for controlling a computing system is provided. The program makes a processor execute the procedure for: receiving, as input, the coordinates of the points on a contour of the flooded area; calculating the inundation level of the section containing the contour of the flooded area by adding prescribed inundation depth to the altitude of the ground of the section; receiving, as input, the inundation depth at a first point in the flooded area; calculating the inundation level of the section containing the first point by adding the inundation depth at the first point to the altitude of the ground of the section containing the first point; calculating the inundation level of the section contained in the flooded area by space-interpolating the calculated inundation level; calculating the inundation depth of the section by subtracting the altitude of the ground of the section from the calculated inundation level of the section; and outputting the calculated inundation depth of the section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The technology disclosed in this specification relates to a program that supports on-site investigation of flood damage. The technology disclosed in the present specification particularly relates to a program for spatially interpolating the inundation depth for each survey point obtained by a field survey in an area that has suffered flood damage.

  In recent years, flood damage due to torrential rains and typhoons has frequently occurred, and effective measures to reduce the damage have been demanded. In order to reduce damage, it is effective to investigate the damage situation and estimate the cause. Under such circumstances, investigations of actual flood damage are being conducted. In the survey, the inundation depth and inundation area are mainly measured. Here, the inundation depth is the maximum water depth generated at a certain point in a certain flood. The flooded area is an area that has been flooded due to a flood. The isoline where the inundation depth is 0 is defined as the boundary of the inundation area.

  Non-patent document 1 can be cited as a document describing a method for investigating the inundation depth. The investigation method is as follows; the authors of Non-Patent Document 1 measured the inundation depth at 146 points in an area inundated by a certain flood. For the measurement, a surveying device called a laser rangefinder was used. With this device, the elevation difference between a point and another point visible from that point can be measured. They measured the difference in elevation between the elevation point and the traces of the water surface visible from that point. Here, the altitude point is a point where the latitude, longitude, and altitude are publicized by the administrative agency, and exists in an area managed by the administrative agency such as a road. In Japanese cities, altitude points are set at intervals of about 100m to 1000m. The altitude accuracy of the altitude point is considered to be about 0.1m. In addition, the traces of the water surface are mud left on urban structures such as buildings, fences, roadside trees, utility poles, etc., and the traces of the water surface coincide with the highest water surface generated at that point in the flood. Conceivable. The authors of Non-Patent Document 1 set the elevation difference measured in this way as the inundation depth. Furthermore, they created a distribution map of the inundation level using the value obtained by adding the altitude of the elevation point to the inundation depth as the inundation level (that is, the elevation of the surface of the water when it was submerged).

  In addition, Non-Patent Document 2 describes the investigation results of the flooded area. Non-Patent Document 2 describes that the flooded area was estimated from aerial photographs. According to Non-Patent Document 2, the shape of the flooded area is represented on the map by surrounding the flooded area with a line segment. As described above, the field investigation of the inundation depth and the field investigation of the inundation area have conventionally been performed by independent methods.

  Recently, a technique called aeronautical laser measurement has been developed, and the altitude of the ground surface can be measured with an accuracy of about 0.1 m and a spatial resolution of about 5 m. If this aviation laser measurement technique is used, it is considered that an altitude with the same accuracy as the altitude point can be obtained at intervals of 5 m.

Technology related to flood damage using this highly accurate topographic data has been developed. As an example thereof, there is a “method for measuring an occupation rate according to altitude and a method for correcting inundation depth using the same” described in Patent Document 1. Patent Document 1 discloses a method for calculating a feature occupancy rate from high-density elevation data and a simulation accuracy using the feature occupancy rate in order to accurately grasp the behavior of a flood current in a dense urban area such as an urban area. A method for improving the above is disclosed. In this method, first, the altitude data in the grid is separated into either “ground” or “feature”. Next, the feature occupation ratio r at an altitude h is calculated as r (h) = n (h) / N. Here, N is the total number of elevation data points in the grid, and n (h) is the number of elevation data points of the “feature” at a certain elevation h. Further, using this r (h), the water level h obtained in the flood simulation is corrected. It is described that the accuracy of simulation results can be improved by this method in urban areas where the features have a great influence on the flood flow.
JP 2005-172634 A Yamamoto Hirofumi, Fukui City Asuwa River left bank and inundation damage in Sabae City Kawawada area, July 2004 Niigata and Fukushima, Fukui heavy rain disaster investigation research, 2004 scientific research grants (Special Research Promotion Fund (1) ) Research report, issue number 16800001, p121, 2007. Robert J. et al. Connell, David J. et al. Painter, and Cornel Beffa: Two-dimensional flood plane flow. II: model validation, Journal of hydrologic engineering, American society of civil engineers, Volume 6, Issue 5, pp. 406-415, 2001.

  Inundation damage depends strongly on the inundation depth, not the inundation level. Since this inundation depth changes on a small spatial scale, in order to know the surface distribution of inundation damage, not only the inundation depth at the surveyed site but also the surface distribution of the inundation depth is necessary. However, the conventional technique cannot determine the surface distribution of the inundation depth. For example, in Non-Patent Document 1, while calculating the surface distribution of the inundation level from the inundation levels measured at a plurality of points, the inundation depth is not obtained except for the investigated point.

  In general, spatial interpolation is used to estimate the distribution of information from information at a plurality of points. Therefore, the inventors first tried to spatially interpolate the inundation depth. However, it has been found that this method has the following two problems.

  The first problem is that the obtained inundation depth distribution is unnatural. This is considered to be due to spatial interpolation of values measured on a spatial scale coarser than the inundation depth spatial scale.

  The second problem is that the inundation depth distribution obtained may be inconsistent with the inundation area obtained in the field survey. As mentioned above, the inundation depth and inundation area are obtained by independent field surveys. However, these pieces of information are not independent. From the definition of the inundation area, the inundation depth must be 0 at the point outside the boundary of the inundation area, and the inundation depth must be greater than 0 at the point inside the boundary of the inundation area. The inundation depth distribution obtained by interpolation using only the inundation depth does not always satisfy this restriction given to the inundation depth distribution by the inundation area.

  As a method for solving the first problem, a method for measuring the inundation level and obtaining the inundation depth distribution as in Non-Patent Document 1 can be considered. It is clear from the definition that the inundation depth is obtained by subtracting the altitude from the inundation level, so it can be said that the inundation depth distribution is obtained by subtracting the altitude distribution from the inundation level distribution. However, as described above, since a surveying device is required for measuring the inundation level, the inundation level is not measured in a normal field survey. In normal field surveys, only inundation depths that do not require surveying equipment are measured. Therefore, this method cannot be applied to normal field surveys.

  As another method for solving the first problem, a method of spatially reducing the measurement interval of the inundation depth can be considered. Furthermore, if the measurement interval of the inundation depth is made infinitely small in the vicinity where the inundation depth becomes zero, the inundation area can be expressed by the inundation depth distribution, so not only the first problem but also the second problem. can be solved. However, this method is very time consuming. Therefore, this method is not practical.

  As described above, from an industrial point of view, it can be said that a method of appropriately estimating the inundation depth distribution in the inundation area using the inundation depth and the inundation area obtained by the conventional field survey as inputs is desirable.

  The present invention has been made in view of these problems, and an object thereof is to estimate the surface distribution of the inundation depth from the inundation depth at a plurality of points.

  A representative invention disclosed in the present application is a program for controlling a computer system, and the computer system includes: a storage device in which the program is stored; and a processor that executes the program stored in the storage device. The program includes a first procedure for accepting coordinates of points on the contour of the flooded area as input, and a flooding level of a plurality of sections including the contour of the flooded area as a predetermined altitude of the ground in each section. A second procedure for calculating by adding the inundation depth, a third procedure for accepting as an input the inundation depth at one or more first points in the inundation area, and the inundation level of the section including the first point, Calculated by adding the inundation depth of the first point to the altitude of the ground of the section including the first point, the second step, and the fourth step. By spatially interpolating the inundation level, among the sections included in the inundation area, a fifth procedure for calculating the inundation level of a section not including the first point, and the section of the section calculated by the fifth procedure A sixth procedure for calculating the inundation depth of the section by subtracting the altitude of the ground of the section from the inundation level, and a seventh procedure for outputting the calculated inundation depth of the section to the processor. It is made to perform.

  According to one embodiment of the present invention, the inundation depth at a point other than the survey point can be calculated. Therefore, based on the result of investigating the inundation depth at several points, the inundation depth distribution of an entire region can be calculated. This makes it easier to grasp the overall picture of flood damage.

  Moreover, as the input data, not the inundation level that needs to be measured by a special device but the inundation depth that can be measured by a general device can be used. This reduces the labor of field surveys.

  First, the outline of the present invention will be described.

  In the present invention, the inundation depth is converted into an inundation level having a larger spatial scale, and the inundation level is spatially interpolated using a natural law that the inundation level follows. The present invention is based on the inventors' three findings. The present invention can be said to be effective with an accuracy that allows the assumptions based on these findings to be considered valid.

  The first discovery is that it can be assumed that the spatial scale of the inundation level is larger than the spatial scale of the inundation depth. This discovery is based on specific-head in hydraulics. According to this theory, when the flow is slow like water damage, it can be said that the water level is less likely to change than the water depth. When this assumption holds, even if the result of interpolating the inundation depth measured at a certain interval is unnatural, the result of interpolating the inundation level measured at the same interval may be natural.

  The second discovery is that it is possible to assume that the altitude of an arbitrary place can be estimated by using altitude data that has recently been obtained. For example, the measurement interval of data obtained by aviation laser measurement is considered to be smaller than the altitude spatial scale. Therefore, it is considered that the altitude of an arbitrary place can be accurately estimated by using this data. If the altitude at an arbitrary location is obtained, the inundation depth measured at an arbitrary location can be converted into an inundation level that is a value obtained by adding the altitude to that value. Similarly, the inundation level distribution can be converted into an inundation depth distribution that is a distribution obtained by subtracting the elevation distribution from the distribution.

The third discovery is that the inundation level wlev is the Laplace equation.
div (grad (wlev)) = 0 Equation (1)
It can be assumed that However, div () is a function that returns an argument divergence, and grad () is a function that returns an argument gradient. When equation (1) holds, the problem of determining the inundation level distribution in the inundation area results in a mathematical problem known as the Dirichlet problem. The Dirichlet problem is a problem in which a value at the boundary of a region is given as a boundary condition to a function that satisfies the Laplace equation, and a distribution inside the region is obtained.

  The assumption of equation (1) is considered valid because it can be considered that a hydrostatic balance is established in a flood. When hydrostatic equilibrium is established, the spatial change grad (p) of the pressure p is proportional to the spatial change grad (wlev) of the water level wlev. Further, it is known that the pressure p satisfies the Laplace equation div (grad (p)) = 0. Therefore, when hydrostatic pressure equilibrium is established, the water level wlev can be regarded as satisfying the Laplace equation.

  The boundary condition given to the equation (1) is the inundation level at the boundary of the inundation area. From the definition of the flooded area, the flood depth is 0 at the boundary of the flooded area. Therefore, the inundation level at the boundary of the inundation area becomes the same value as the altitude.

  The inundation depth interpolation method devised by the inventors based on these findings comprises the following steps: First, the space is divided into sections of arbitrary shape, and an elevation is given to each section. At this time, altitude data having sufficient accuracy and spatial resolution is used. Next, the inundation level in the section including the point where the inundation depth is measured is calculated. Similarly, the inundation level in the section including the boundary line of the inundation area is calculated. Furthermore, the inundation level of the section included in the inundation area is interpolated on the assumption that the inundation level satisfies the Laplace equation. The inundation depth is calculated by subtracting the altitude from the inundation level for each section. Through the above steps, the inundation depth for each section is obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A system in which an assumed user is a specific one is shown as a first embodiment, and a system in which an assumed number of users is an unspecified number is shown as a second embodiment.

  First, a first embodiment of the present invention will be described.

  FIG. 1 is a schematic block diagram showing the configuration of the computer system according to the first embodiment of this invention.

  The computer system of the present embodiment is configured by a PC (Personal Computer) 100. The PC 100 includes an input / output unit 110. The user operates the system from the input / output unit 110. The input / output unit 110 includes an input unit including a keyboard 111 and a mouse 112, for example, and an output unit including a display 113, for example. The user can input a command from the input unit and check the result from the output unit.

  The PC 100 further includes a memory 120 and a CPU (Central Processing Unit) 130. An input support program 141 and an inundation depth interpolation program 142 are developed in the memory 120. The input support program 141 and the inundation depth interpolation program 142 can transmit and receive data and commands to and from each other. Based on the input support program 141 and the inundation depth interpolation program 142, the CPU 130 executes a command. Accordingly, the processing executed by the input support program 141 and the inundation depth interpolation program 142 in the following description is actually executed by the CPU 130 based on the input support program 141 and the inundation depth interpolation program 142.

  In FIG. 1, the input support program 141 and the inundation depth interpolation program 142 are described as independent programs. However, these programs may be program modules constituting one program.

  The input support program 141 and the inundation depth interpolation program 142 include map data 191, inundation area data 192, inundation point data 193, inundation depth distribution data 194, altitude data 195, and disaster data stored in an HDD (Hard Disk Drive) 190. Data 196 is read as necessary. The HDD 190 may be built in the PC 100 or connected to the outside of the PC 100.

  The inundation area data 192, the inundation point data 193, the inundation depth distribution data 194, and the disaster data 196 will be described in detail later (see FIGS. 7, 9, 12, and 3 respectively). The map data 191 includes at least map information of a region including a flooded area in a disaster registered in the disaster data 196. The altitude data 195 includes at least altitude values of the ground in the area including the flooded area. This embodiment is based on the assumption that the altitude data 195 has an accuracy of about 0.1 m and a spatial resolution of about 5 m. Such altitude data 195 is obtained by a technique such as aviation laser measurement.

  FIG. 1 shows a configuration in which the input support program 141 and the inundation depth interpolation program 142 are expanded in the same memory 120. However, as long as the input support program 141 and the inundation depth interpolation program 142 can transmit and receive data and commands to each other, the programs may be developed in different memories. In any case, the input support program 141 and the inundation depth interpolation program 142 may transmit and receive data and commands by inter-process communication.

  FIG. 2 is a sequence diagram illustrating a first process executed by the PC 100 according to the first embodiment of this invention.

  Hereinafter, the processing sequence of the system will be described with reference to FIG.

  When the input support program 141 is activated on the PC 100, the input support program 141 reads the disaster data 196 from the HDD 190 (step 201). The input support program 141 that has read the data outputs a first GUI (Graphical User Interface) including the window 300 to the display 113 (step 202).

  FIG. 3 is an explanatory diagram illustrating a first GUI provided by the input support program 141 according to the first embodiment of this invention.

  3 includes a window 300 displayed in a predetermined area of the display 113, and receives input from the keyboard 111 and the mouse 112. Using this GUI, the user selects an interesting flood record (step 203). In the present embodiment, the flood damage record is selected by the user selecting the selection button 301 and pressing the “next” button 302.

  In the window 300, a table 310 including one or more records is displayed. The table 310 is generated based on disaster data 196 stored in the HDD 190. Each record of the table 310 describes information used for the user to uniquely identify a disaster. In the example of FIG. 3, the name 312 of the disaster and the address 313 of the representative point (that is, the representative point) in the disaster are described. Furthermore, a unique number (that is, disaster ID) 311 generated by a predetermined method is given to each record of the disaster data 196. Furthermore, in the example of FIG. 3, a blank record 303 is prepared. When the user is interested in a disaster that does not exist in the disaster data 196, the user can input a record using the keyboard 111, the mouse 112, and the like in this blank record.

The input support program 141 reads the map data 191 around the representative point 313 of the record selected in step 203. Furthermore, the input support program 141 sets a record (hereinafter referred to as a corresponding record) having a disaster ID that matches the disaster ID 311 of the record selected in step 203, the inundation area data 192, the inundation point data 193, and the inundation depth distribution. Read from each of the data 194 (step 204). The result of step 204 is
Case A: When the corresponding record does not exist in the inundation area data Case B: It can be classified into two types when the corresponding record exists in the inundation area data. In case A, there is no record corresponding to both the inundation point data and the inundation depth distribution data as well as the inundation area data. In case B, there may be records corresponding to the inundation point data and the inundation depth distribution data.

  The input support program 141 outputs the second GUI including the window 400 to the display 113 based on the map data 191 read in step 204 (step 205).

  FIG. 4 is an explanatory diagram illustrating an initial state of the second GUI provided by the input support program 141 according to the first embodiment of this invention.

  The GUI in FIG. 4 includes a window 400 displayed in a predetermined area of the display 113 and receives input from the keyboard 111 and the mouse 112. In the window 400, at least a map 410 is displayed. Further, the window 400 has at least a function that allows the user to specify a polygonal inundation area and to specify the inundation depth of one or more points. As will be described later, the mouse pointer 401 is used to designate the flooded area and the flooded depth.

  The map 410 is a map of an area including a flooded area in the selected disaster. It is desirable that the scale of the map 410 is approximately the same as the spatial scale of the inundation distribution. For typical cities, 1 / 25,000 to 1/500 is considered appropriate. A water channel 411 and a road 412 can be displayed on the map 410.

  FIG. 5 is a sequence diagram illustrating a second process executed by the PC 100 according to the first embodiment of this invention.

  First, the user inputs the shape of the flooded area in the window 400 (step 501). This step is necessary for Case A in Step 204 described above. In case B, since the data to be created in this step has already been acquired in step 204, step 501 can be omitted.

  FIG. 6 is an explanatory diagram showing the second GUI in a state where a flooded area is being input in the first embodiment of the present invention.

  Using this GUI, the user inputs the shape of the flooded flooded area selected in step 230. In the present embodiment, the user inputs the shape of the flooded area as a polygon (a two-dimensional closed polygon composed of three or more vertices). The user designates one point of the map 410 with the mouse pointer 401 and clicks the mouse 112 to designate the vertex of the polygon. One point on the map 410 indicated at this time is an arbitrary point on the contour line of the flooded area. The contour line of the flooded area is a boundary line between a region where the depth of flooding is 0 (that is, a region that is not flooded) and a region where the depth of flooding is greater than 0 (that is, a region that is flooded).

  In this way, by repeating the operation of inputting points on the contour of the flooded area three or more times in the direction of going around the flooded area, three or more vertices are designated. When the user presses the confirm button 402, the input support program 141 creates a polygon 625 by following the vertices in the order of input. Then, the input support program 141 creates flooded area data 192 corresponding to the polygon 625.

  FIG. 7 is an explanatory diagram illustrating a data structure of the flooded area data 192 according to the first embodiment of this invention.

  The flooded area data 192 includes at least an ID (identifier) that uniquely identifies a disaster, an ID that uniquely identifies the flooded area, the position of the vertex of the polygon indicating the flooded area, and the order of the vertex. In the present embodiment, the flooded area data 192 includes a disaster ID 701, a flooded area ID 702, a vertex ID 703, a next vertex ID 704, a vertex longitude 705 and a latitude 706.

  The disaster ID 701 is an identifier for uniquely identifying a disaster, like the disaster ID 311 in FIG.

  The flooded area ID 702 is an identifier of the flooded area. A unique number is assigned as a flooded area ID 402 for each flooded area, that is, for each polygon.

  The vertex ID 703 is an identifier of the vertex of the input polygon.

  The next vertex ID 704 is an identifier of the vertex input next to the vertex identified by the vertex ID 703.

  The longitude 705 and latitude 706 are the longitude and latitude of the vertex identified by the vertex ID 703.

  After the inundation area data is input in this way, the inundation depth interpolation program 141 prompts the user to input inundation point data (step 502). This step 502 can be omitted. In the case of Case A in Step 204 described above, if this Step 502 is omitted, there is no inundation point record. In the case of Case B in step 204 described above, if this step 502 is omitted, there is a possibility that no inundation point record exists. If there is no inundation point record, spatial interpolation based on only the inundation depth at the boundary of the inundation area 625 is executed in step 505 described later.

  FIG. 8 is an explanatory diagram showing the second GUI in a state where the inundation point is being input in the first embodiment of the present invention.

  The user can input the inundation depth of one or more points included in the inundation area 625. In the present embodiment, the input support program 141 displays an icon 824 at a point designated by the mouse pointer 401. The user can input the inundation depth at the point in cm using the keyboard 111.

  In order to make it easier for the user to grasp the input position, it is desirable that the icon 824 in the state of waiting for the entry of the inundation depth is displayed in a different form from the icons 821, 822, and 823 for which the inundation depth has been entered. In the example of FIG. 8, the icon 824 is displayed as a broken-line circle, and the icons 821, 822, and 823 are displayed as a solid-line circle.

  Finally, when the user presses the confirmation button 402, inundation point data 193 corresponding to the icons 821, 822, 823, and 824 is generated. The user is allowed to designate a point inside the flooded area as the flooded point. In order to realize this, the input support program 141 only needs to make the icon 824 waiting for input of the inundation depth appear only when the user clicks a point inside the inundation area.

  FIG. 9 is an explanatory diagram illustrating a data structure of the inundation point data 193 according to the first embodiment of this invention.

  The inundation point data 193 includes at least an ID for uniquely identifying the disaster, an ID for uniquely identifying the inundation area, the position of the survey point, and information on the inundation depth of the point. For example, in the present embodiment, the inundation point data 193 is composed of one or more records. However, the inundation area ID that does not exist in the inundation area data does not exist in the inundation area ID of the inundation point data. That is, if the user has not yet entered the inundation depth, the inundation point data 193 does not include a record. One record includes a disaster ID 901, a flooded area ID 902, a survey point longitude 903, a survey point latitude 904, and a survey point flooded depth 905.

  The disaster ID 901 is an identifier for uniquely identifying a disaster, like the disaster ID 311 in FIG.

  The flooded area ID 902 is an identifier for identifying the flooded area, like the flooded area ID 702 of FIG.

  The longitude 903, the latitude 904, and the inundation depth 905 are values inputted as the coordinates of the survey point designated by the user and the inundation depth at that point.

  After the inundation point data is input in this way, the input support program 141 prompts the user to press the confirmation button 402. When the user presses the confirm button 402, the flooded area data 192 created in step 501 and the flooded spot data 193 created in step 502 are confirmed (step 503).

  Next, the input support program 141 transmits a request for inundation depth interpolation to the inundation depth interpolation program 142 (step 504). At this time, the input support program 141 transmits the inundation area data 192 and the inundation point data 193 determined in step 503 to the inundation depth interpolation program 142.

  The inundation depth interpolation program 142 that has received the request for inundation depth interpolation from the input support program 141 executes the inundation depth interpolation process (step 505).

  FIG. 10 is a PAD (Problem Analysis Diagram) diagram showing details of the inundation depth interpolation process (step 505) according to the first embodiment of this invention.

  This process includes steps 1001 to 1013. Prior to this processing, a grid is created in advance in the space by a predetermined method. Here, the lattice is one small region (that is, a section) when the space is divided into a plurality of small regions.

  FIG. 11 is an explanatory diagram showing a positional relationship between the inundation point, the inundation area, and the grid in the first embodiment of the present invention.

  Since the present invention does not depend on the grid division method, in the present invention, each grid may have any shape and any size. However, when all the grids have a uniform shape, the calculation load of the inundation depth interpolation process is lighter than that when it is not. In addition, when the grid interval is coarse (that is, the size of each grid is large), the calculation load is lighter than that when the grid interval is fine, and the obtained inundation depth distribution is also coarse. Therefore, the shape and size of the grid may be determined in consideration of the calculation load and the like and the spatial resolution of the inundation depth distribution to be obtained.

  For example, sections obtained by dividing an area including a flooded area in the east-west direction and the north-south direction at predetermined intervals may be used as a lattice. Or it is good also considering the site of a house as a lattice.

  In this embodiment, a method of dividing into 5 m grids in the east-west direction and 5 m grids in the north-south direction in the UTM (Universal Transverse Mercator) coordinate system is adopted. This is a mesh data representation suitable for fine spatial scale distribution. Further, two numbers obtained by arranging the distance along the east-west direction from the origin to the lattice and the distance along the north-south direction were defined as the lattice ID. The two numbers (i, j) may be calculated by the following formula.

i = floor (x / dx); j = floor (y / dy);
However, x and y are the x coordinate value and the y coordinate value in the UTM coordinate, respectively. dx and dy are the grid size in the east-west direction and the grid size in the north-south direction, respectively. i and j are the number of grids counted from the origin along the east-west direction and the number of grids counted from the origin along the north-south direction, respectively. floor () is a function that truncates the decimal part of the argument and returns an integer.

  Note that the lattice ID may be determined by a method other than the above as long as each lattice is uniquely identified.

  In step 1001, the inundation depth interpolation program 142 repeats step 1002 for the grid including the inundation point. As shown in the legend 1101, the inundation point is, for example, the position where the icon 824 is displayed. Therefore, the lattice to be processed in step 1002 is, for example, the lattice 1121.

  In step 1002, the inundation depth interpolation program 142 calculates the inundation level in the processing target lattice (for example, the lattice 1121). The value of the inundation level is calculated by adding the altitude to the inundation depth 905 of the inundation point data 193. The elevation in the lattice is acquired by referring to the elevation data 195 stored in the HDD 190.

  In step 1003, the inundation depth interpolation program 142 repeats step 1004 for the grid including the boundary of the inundation area (that is, the outline of the inundation area). In FIG. 11, the boundary line of the flooded area is a boundary line 1111. Therefore, the lattice to be processed in step 1004 is, for example, the lattice 1122. Note that if the inundation point data 193 has been input for the grid including the boundary line of the flooded area, the grid has already been processed in step 1002 and is not processed in step 1004.

  In step 1004, the inundation depth interpolation program 142 calculates the inundation level in the lattice. The method for calculating the inundation level is the same as in step 1002. However, unlike step 1002, 0 is given as the inundation depth at the boundary of the inundation area. Depending on the inundation area survey method, the inundation depth may not be zero at the boundary of the inundation area, and there may be some errors. In this case, a value obtained by adding the error to the altitude may be set as the inundation level.

  In step 1005, the inundation depth interpolation program 142 selects a grid to be interpolated. The grid to be interpolated is a grid that is inside the boundary line of the flooded area, does not include the flooded point data, and does not include the boundary line of the flooded area. In FIG. 11, the lattice to be interpolated is, for example, a lattice 1123.

Thereafter, in steps 1006 to 1011, the inundation depth interpolation program 142 solves the Laplace equation div (grad (wlev)) = 0. In the present embodiment, since a uniform lattice is used, the Laplace equation represented by the equation (1) is discretized as, for example, the following equation (2).
wlev [i, j] = 1/6 * ((wlev [i-1, j] + wlev [i + 1, j] + wlev [i, j-1] + wlev [i, j + 1]) + 1/2 * (wlev [i −1, j−1] + wlev [i + 1, j−1] + wlev [i−1, j + 1] + wlev [i + 1, j + 1])) Equation (2)
However, wlev [i, j] represents the water level wlev in the lattice (i, j). In order to solve the equation (2), an averaging process or a matrix solution method such as a SOR method (successive over-relaxation method) can be used. In the present embodiment, steps 1006 to 1011 show a method using an averaging process that is easy to understand.

In addition, the discretization method of Formula (1) is not restricted to Formula (2). In the formula (2), discretization is performed using eight neighboring grids, but the following formula (3) discretized using four neighboring grids may be used, for example.
wlev [i, j] = 1/4 * ((wlev [i-1, j] + wlev [i + 1, j] + wlev [i, j-1] + wlev [i, j + 1])) Equation (3)
As described above, in the present embodiment, solving the Laplace equation represented by the equation (1) means that a predetermined count (in the above example, 1/6) is applied to the inundation levels of a plurality of lattices adjacent to the lattice to be treated. , ½, ¼, etc.) and a plurality of the calculated values are added.

  The eight neighboring grids are eight grids adjacent to the processing target grid. Specifically, eight grids adjacent to the north, northwest, west, southwest, south, southeast, east, and northeast of the grid to be processed. On the other hand, the four neighboring grids are four grids adjacent to the grid to be processed. Specifically, four grids adjacent to the north, west, south, and east of the grid to be processed.

  In step 1006, the inundation depth interpolation program 142 repeats step 1007 and subsequent steps while the selected grid exists.

  In step 1007, the inundation depth interpolation program 142 repeats step 1008 and subsequent steps for the grid selected at that time.

  In step 1008, the inundation depth interpolation program 142 calculates the inundation level in the grid to be processed using the equation (2). Alternatively, in step 1008, equation (3) above may be used.

  In step 1009, the inundation depth interpolation program 142 calculates the amount of change in the inundation level of the grid to be processed (that is, the difference between the inundation level calculated at the present time and the inundation level before the previous step 1008 is executed). (Absolute value) is calculated. The inundation depth interpolation program 142 executes step 1010 when the change amount is equal to or less than the threshold value, and executes step 1011 otherwise. Here, the threshold value is set to a value smaller than the interpolation accuracy to be obtained. The specific value of the threshold value may be determined empirically. The inventors considered that an interpolation accuracy of about 0.1 m is appropriate and set the threshold value to 0.05 m.

  In step 1010, the inundation depth interpolation program 142 cancels the selection of the grid to be processed. The released lattice is not subjected to the processing subsequent to step 1008 unless it is selected again as a processing target.

  In step 1011, the inundation depth interpolation program 142 selects an interpolation target grid in the vicinity of 8 of the processing target grid. When equation (2) is used in step 1008, in step 1011, the inundation depth interpolation program 142 selects the interpolation target grid in the vicinity of the four grids to be processed. Since the grid to be processed is already selected, step 1008 is repeatedly executed until the selection is canceled in step 1010.

  In step 1012, the inundation depth interpolation program 142 executes step 1013 for the lattice to which the inundation level is given in the previous step.

  In step 1013, the inundation depth interpolation program 142 calculates the inundation depth from the inundation level in the grid to be processed. Specifically, the inundation depth is calculated by subtracting the altitude of the grid from the inundation level of the grid to be treated.

  As described above, the inundation depth interpolation process (step 505) is completed by the steps shown in FIG. Thereby, the inundation depth distribution data reflecting the inundation area shape and the inundation point data input by the user was generated.

  FIG. 12 is an explanatory diagram illustrating a data structure of the inundation depth distribution data 194 according to the first embodiment of this invention.

  The inundation depth distribution data 194 includes at least information of a disaster ID 1201 that uniquely identifies a disaster, an inundation area ID 1202 that uniquely identifies an inundation area, a lattice ID 1203 that uniquely identifies a grid, and an inundation depth 1204 of the grid.

  The inundation depth interpolation program 142 stores the inundation depth distribution data 194 created in step 505 in the HDD 190. Further, the inundation depth interpolation program 142 stores the inundation area data 192 and the inundation point data 193 received in Step 504 in the HDD 190 (Step 506).

  Further, the inundation depth interpolation program 142 transmits the created inundation depth distribution data 194 to the input support program 141 (step 507). The input support program 141 outputs the received inundation depth distribution data to the map 410 (step 508).

  FIG. 13 is an explanatory diagram illustrating a state in which the second GUI provided by the input support program 141 according to the first embodiment of this invention displays the inundation depth distribution.

  Comparing FIG. 13 with FIG. 8, the icon at the flooding point input by the user in step 502 is changed from the icon 824 waiting for input to the icon 1324 in the finalized state. Furthermore, the inundation depth distribution 1325 was displayed. In addition, about the grating | lattice (for example, grating | lattice 1322) containing the boundary line of an inundation area, the whole grating | lattice is not displayed as it is, but only the part contained in an inundation area is displayed. As a result, the shape of the inundation area input by the user is equal to the shape of the inundation area to be finally displayed, which is in line with the user's intuition.

  The inundation depth distribution 1325 may be displayed by any method. For example, the inundation depth distribution 1325 may display the inundation depth 1204 by coating each grid with a color corresponding to the inundation depth 1204. Specifically, the value (or range of values) of the inundation depth 1204 may be associated with a predetermined color, and the color corresponding to the inundation depth 1204 of each grid may be displayed in the inundation depth distribution 1325. Alternatively, a predetermined pattern or figure corresponding to the inundation depth 1204 may be displayed. In the legend 1341, it is desirable to describe the correspondence between the color (or pattern or figure) and the water immersion depth 1204.

  In the example of FIG. 13, the inundation depth from 0 cm to 50 cm is displayed by a thin diagonal line that descends to the right, and the inundation depth that exceeds 50 cm is displayed by a thick oblique line that rises to the right.

  In step 509, the input support program 141 prompts the user to input flooding point data or an instruction to end the program, and accepts input from the user. This step cannot be omitted in either case A or case B in step 204 described above. In the present embodiment, when the user inputs the same operation as in step 502, that is, the inundation depth at one or more points on the map 410, the input support program 141 repeats the processing after step 502 again. On the other hand, when the user presses the end command button 403, the input support program 141 ends.

  In the first embodiment of the present invention described above, as shown in FIG. 1, the computer system that causes the PC 100 to operate the input support program 141 and the inundation depth interpolation program 142 is shown. However, the same processing as that of the above computer system may be executed by a computer system in which a client computer and a server computer are connected via the Internet. In this case, the server computer can accept the inundation point data from many client computers.

  FIG. 14 is a schematic block diagram showing a configuration of a computer system according to the second embodiment of this invention.

  The computer system of FIG. 14 includes a client computer 101 and a server computer 102. The client computer 101 and the server computer 102 are connected via the Internet 150.

  The client computer 101 includes an input / output unit 110. The input / output unit 110 has the same configuration as that described in the first embodiment. The client computer 101 further includes a memory 121 and a CPU 131. Based on the input support program 141 developed in the memory 121, the CPU 131 executes an instruction. Therefore, the processing executed by the input support program 141 is actually executed by the CPU 131 based on the input support program 141.

  The server computer 102 includes a memory 122 and a CPU 132. Based on the inundation depth interpolation program 142 developed in the memory 122, the CPU 132 executes an instruction. Therefore, the processing executed by the inundation depth interpolation program 142 is actually executed by the CPU 132 based on the inundation depth interpolation program 142. The inundation depth interpolation program 142 reads map data 191, inundation area data 192, inundation point data 193, inundation depth distribution data 194, altitude data 195, and disaster data 196 stored in the HDD 190 as necessary. The HDD 190 may be built in the server computer 102 or connected to the outside of the server computer 102.

  FIG. 14 shows a configuration in which the client computer 101 and the server computer 102 are connected via the Internet 150, but the Internet 150 may be replaced by any other type of network.

  The input support program 141 and the inundation depth interpolation program 142 of the second embodiment execute the same processing as the input support program 141 and the inundation depth interpolation program 142 of the first embodiment. For this reason, the description about the process which these programs perform in 2nd Embodiment is abbreviate | omitted. However, in the second embodiment, data transmitted and received between the input support program 141 and the inundation depth interpolation program 142 passes through the Internet 150.

  According to the first and second embodiments of the present invention, it is possible to estimate a fine inundation depth distribution based on the inundation depth measured at coarse intervals. Furthermore, according to the second embodiment of the present invention, it is possible to collect inundation point data through the Internet and estimate the inundation depth distribution based on the data. For this reason, the data regarding flood damage measured by the general public can be used effectively. For this reason, it is possible to reduce the time and labor required for the field investigation of the actual inundation results.

It is a schematic block diagram which shows the structure of the computer system of the 1st Embodiment of this invention. It is a sequence diagram which shows the 1st process performed by PC of the 1st Embodiment of this invention. It is explanatory drawing which shows 1st GUI which the input assistance program of the 1st Embodiment of this invention provides. It is explanatory drawing which shows the initial state of 2nd GUI which the input assistance program of the 1st Embodiment of this invention provides. It is a sequence diagram which shows the 2nd process performed by PC of the 1st Embodiment of this invention. In 1st Embodiment of this invention, it is explanatory drawing which shows 2nd GUI in the state which is inputting the flooded area. It is explanatory drawing which shows the data structure of the flooded area data of the 1st Embodiment of this invention. In 1st Embodiment of this invention, it is explanatory drawing which shows 2nd GUI in the state which is inputting the inundation point. It is explanatory drawing which shows the data structure of the inundation point data of the 1st Embodiment of this invention. It is a PAD figure which shows the detail of the inundation depth interpolation process of the 1st Embodiment of this invention. It is explanatory drawing which shows each positional relationship of the flooding point in the 1st Embodiment of this invention, a flooded area, and a grating | lattice. It is explanatory drawing which shows the data structure of the inundation depth distribution data of the 1st Embodiment of this invention. It is explanatory drawing which shows the state which 2nd GUI which the input assistance program of the 1st Embodiment of this invention provides displayed the inundation depth distribution. It is a schematic block diagram which shows the structure of the computer system of the 2nd Embodiment of this invention.

Explanation of symbols

100 PC
141 Input support program 142 Inundation depth interpolation program 192 Inundation area data 193 Inundation point data 194 Inundation depth distribution data 195 Elevation data

Claims (20)

A program for controlling a computer system,
The computer system includes a storage device in which the program is stored, and a processor that executes the program stored in the storage device,
The program is
A first procedure for accepting as input the coordinates of a point on the contour of the flooded area;
A second procedure for calculating the inundation level of a plurality of sections including the contour line of the inundation area by adding a predetermined inundation depth to the altitude of the ground of each section;
A third procedure for accepting as an input the inundation depth at one or more first points in the inundation area;
A fourth step of calculating the inundation level of the section including the first point by adding the inundation depth of the first point to the altitude of the ground of the section including the first point;
A fifth procedure for calculating the inundation level of a section that does not include the first point among the sections included in the submerged area by spatially interpolating the inundation level calculated by the second procedure and the fourth procedure. When,
A sixth procedure for calculating the inundation depth of the section by subtracting the elevation of the ground of the section from the inundation level of the section calculated by the fifth procedure;
A program for causing the processor to execute a seventh procedure for outputting the calculated inundation depth of the section.   In the fifth procedure, the inundation level of the section not including the first point is the inundation level calculated by the second procedure and the fourth procedure, and the inundation level of the section not including the first point is The program according to claim 1, wherein the program is calculated so as to satisfy a Laplace equation. In the fifth procedure, the inundation level of the first section which is a section not including the first point is obtained by multiplying the inundation levels of a plurality of sections adjacent to the first section by a predetermined count and multiplying the predetermined count. Calculated by adding the inundation levels of multiple compartments,
The fifth procedure includes
Calculating the inundation level of the first section;
Calculating the difference between the calculated value and the previously calculated inundation level of the first section;
And a step of calculating an inundation level of the plurality of sections adjacent to the first section and the first section when an absolute value of the calculated difference is larger than a predetermined threshold. 3. The program according to 3.   The program according to claim 1, wherein the section is generated by dividing an area including the flooded area at a predetermined interval. The computer system further includes a display device,
The seventh procedure includes an eighth procedure in which at least one of the input inundation depth at the first point and the calculated inundation depth in each section is displayed on the display device. Item 1. The program according to item 1. The computer system holds map information of a region including the flooded area,
The seventh procedure further includes a ninth procedure for displaying a map of an area including the flooded area on the display device based on the map information,
On the map displayed by the ninth procedure, the outline of the flooded area is displayed,
The at least one of the input inundation depth of the first point and the calculated inundation depth in each section is displayed on the map displayed by the ninth procedure. 5. The program according to 5.   In the seventh procedure, the display of the calculated inundation depth in each section includes a color associated with the inundation depth in an area in the inundation area among areas corresponding to the respective sections on the map. The program according to claim 6, wherein the program is executed by displaying. The computer system is
Furthermore, a display device and an input device are provided,
Holding identification information of one or more disasters, inundation depth of the first point already input corresponding to each disaster, and map information of the area where each disaster occurred,
The program further includes:
A tenth procedure for displaying the identification information of the disaster on the display device;
An eleventh procedure for accepting one selection of the displayed identification information by the input device;
Based on the held map information, the map of the area including the inundation area in the disaster identified by the selected identification information and the inundation depth of the first point already input corresponding to the disaster And causing the processor to execute a twelfth procedure for displaying on the display device.
The first procedure is executed by accepting designation of a point on the map displayed by the twelfth procedure,
The third procedure is executed by accepting designation of a point on the map displayed by the twelfth procedure, and further accepting an input of an inundation depth at a point corresponding to the designated point. The program according to claim 1. A computer comprising a processor and a storage device connected to the processor,
The processor is
A first procedure for accepting as input the coordinates of a point on the contour of the flooded area;
A second procedure for calculating the inundation level of a plurality of sections including the contour line of the inundation area by adding a predetermined inundation depth to the altitude of the ground of each section;
A third procedure for accepting as an input the inundation depth at one or more first points in the inundation area;
A fourth step of calculating the inundation level of the section including the first point by adding the inundation depth of the first point to the altitude of the ground of the section including the first point;
A fifth procedure for calculating the inundation level of a section that does not include the first point among the sections included in the submerged area by spatially interpolating the inundation level calculated by the second procedure and the fourth procedure. When,
And a sixth procedure for calculating the inundation depth of the section by subtracting the elevation of the ground of the section from the inundation level of the section calculated by the fifth procedure.   In the fifth procedure, the inundation level of the section not including the first point is the inundation level calculated by the second procedure and the fourth procedure, and the inundation level of the section not including the first point is The computer according to claim 9, wherein the computer is calculated so as to satisfy a Laplace equation. In the fifth procedure, the inundation level of the first section which is a section not including the first point is obtained by multiplying the inundation levels of a plurality of sections adjacent to the first section by a predetermined count and multiplying the predetermined count. Calculated by adding the inundation levels of multiple compartments,
The fifth procedure includes
Calculating the inundation level of the first section;
Calculating the difference between the calculated value and the previously calculated inundation level of the first section;
And a step of calculating an inundation level of the plurality of sections adjacent to the first section and the first section when an absolute value of the calculated difference is larger than a predetermined threshold. 9. The computer according to 9.   The computer according to claim 9, wherein the section is generated by dividing an area including the flooded area at a predetermined interval. A computer system comprising a server computer and a client computer connected to the server computer via a network,
The server computer includes a first processor and a first storage device connected to the first processor,
The client computer includes a second processor, a second storage device connected to the second processor, a display device connected to the second processor, and an input device connected to the second processor. ,
The first processor is
A first procedure for receiving coordinates of points on the contour of the flooded area as input via the network;
A second procedure for calculating the inundation level of a plurality of sections including the contour line of the inundation area by adding a predetermined inundation depth to the altitude of the ground of each section;
A third procedure for receiving an inundation depth at one or more first points in the inundation area as an input via the network;
A fourth step of calculating the inundation level of the section including the first point by adding the inundation depth of the first point to the altitude of the ground of the section including the first point;
A fifth procedure for calculating the inundation level of a section that does not include the first point among the sections included in the submerged area by spatially interpolating the inundation level calculated by the second procedure and the fourth procedure. When,
And a sixth procedure for calculating the inundation depth of the section by subtracting the elevation of the ground of the section from the inundation level of the section calculated by the fifth procedure. .   In the fifth procedure, the inundation level of the section not including the first point is the inundation level calculated by the second procedure and the fourth procedure, and the inundation level of the section not including the first point is The computer system according to claim 13, wherein the computer system is calculated so as to satisfy a Laplace equation. In the fifth procedure, the inundation level of the first section which is a section not including the first point is obtained by multiplying the inundation levels of a plurality of sections adjacent to the first section by a predetermined count and multiplying the predetermined count. Calculated by adding the inundation levels of multiple compartments,
The fifth procedure includes
Calculating the inundation level of the first section;
Calculating the difference between the calculated value and the previously calculated inundation level of the first section;
And a step of calculating an inundation level of the plurality of sections adjacent to the first section and the first section when an absolute value of the calculated difference is larger than a predetermined threshold. 13. The computer system according to 13.   The computer system according to claim 13, wherein the section is generated by dividing an area including the flooded area at a predetermined interval. Instructing the first processor to transmit at least one of the input inundation depth at the first point and the calculated inundation depth in each section to the client computer via the network;
The second processor executes a seventh procedure for causing the display device to display at least one of the input inundation depth at the first point and the calculated inundation depth in each section. The computer system according to claim 13. The computer system holds map information of a region including the flooded area,
The seventh procedure further includes an eighth procedure for causing the display device to display a map of an area including the flooded area based on the map information.
In the map displayed by the eighth procedure, the outline of the flooded area is displayed,
The at least one of the input inundation depth of the first point and the calculated inundation depth in each section is displayed on the map displayed by the eighth procedure. 17. The computer system according to 17.   In the seventh procedure, display of the calculated inundation depth in each section is performed by displaying a color associated with the inundation depth in an area in the inundation area among areas corresponding to the respective sections on the map. The computer system according to claim 18, wherein the computer system is executed by displaying. The computer system holds identification information of one or more disasters, the inundation depth of the first point already input corresponding to each disaster, and map information of the area where each disaster has occurred And
The second processor further includes:
A ninth procedure for displaying the identification information of the disaster on the display device;
A tenth procedure for accepting selection of one of the displayed identification information by the input device;
Based on the held map information, the map of the area including the inundation area in the disaster identified by the selected identification information and the inundation depth of the first point already input corresponding to the disaster Eleventh procedure to display on the display device,
A twelfth procedure for receiving a designation of a plurality of points on the map displayed by the eleventh procedure, and an inundation depth of a point corresponding to at least one of the designated plurality of points;
Executing a thirteenth procedure for transmitting at least one coordinate of the plurality of points designated in the twelfth procedure and the inundation depth inputted in the twelfth procedure to the server computer via the network. ,
The first procedure is executed by receiving the coordinates transmitted by the thirteenth procedure,
The computer system according to claim 13, wherein the third procedure is executed by receiving the inundation depth transmitted by the thirteenth procedure.