Mountainous area riverway type reservoir inundation area rapid generation method and system based on DEM

Abstract

The invention relates to the field of water conservancy and hydropower engineering construction land acquisition and physical index investigation, in particular to a method and a system for quickly generating a mountainous area riverway type reservoir inundation area based on a high-precision DEM (Digital Elevation Model), and aims to solve the problems of poor reservoir inundation area generation precision, long time consumption and large personal error in the prior art. The method comprises the following steps: acquiring or generating a reservoir reach DEM, a river section line and a water return meter, and preprocessing; expanding section lines to divide river channel units; calculating a grid water level based on inverse distance weighting interpolation, and comparing the grid water level with DEM elevation to determine a submerged area grid; and generating a closed surface domain through boundary tracking and smoothing processing, and combining to obtain a whole submerged region. The method gives consideration to efficiency and precision, supports second-level dynamic generation of multiple schemes, improves analysis precision and efficiency, is suitable for mountainous river type reservoirs, and provides data support for scheme comparison and selection and object investigation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of land acquisition and physical index investigation for water conservancy and hydropower engineering construction, and particularly relates to a method and system for rapidly generating a reservoir inundation area in a mountainous river channel type reservoir based on DEM. BACKGROUND

[0002] A reservoir inundation area is determined based on a reservoir design flood backwater surface line, taking into account the influence of wind and waves, and determining different reservoir safety superhigh values according to different inundation objects. In the prior art, a method commonly used in the past is to draw a reservoir inundation line by manually drawing on a reference contour line on a topographic map using CAD mapping software according to a cross section and backwater calculation results. In recent years, there has also been a method of linear interpolation encryption of a typical cross section, setting a fixed value according to the principle of water level equidifference, extracting an elevation line according to DEM, and forming different design flood reservoir inundation areas after topological surface construction. In the field of flood reservoir inundation area definition, there has also been a method of fitting a water surface grid file according to a flood water level, using a GIS software grid calculator, performing algebraic operation on the water surface grid file and the DEM file to determine a grid file of the inundation area, and merging the grid into a reservoir inundation area surface file after surface conversion.

[0003] The existing methods mainly have the following problems: 1) manually drawing an inundation processing design flood backwater line for different objects is time-consuming and labor-intensive, and it is difficult to control human error and meet the requirement of rapidly generating a range under the current situation; 2) according to the design flood backwater cross section encryption, the extraction of the elevation line according to the DEM, and the formation of the reservoir inundation area, the density of the cross section encryption is not enough to cause poor accuracy of the reservoir inundation area results, and it is still time-consuming; 3) the method of fitting a water surface grid file according to a flood water level, performing algebraic operation on the water surface grid file and the DEM file to determine an inundation area, and merging the grid into a reservoir inundation area surface file after surface conversion can be used in the simulation analysis of the range of a small river flood, and can also be applied to the extraction of the land acquisition range of a small reservoir in a mountainous area, but for a wide area and high-precision DEM, the calculation is large and time-consuming.

[0004] Therefore, there is an urgent need for a method and system for generating a reservoir inundation area in a mountainous river channel type reservoir that takes into account the calculation efficiency and accuracy. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a method and system for rapidly generating a reservoir inundation area in a mountainous river channel type reservoir based on DEM, to solve at least one of the above technical problems in the prior art.

[0006] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0007] In a first aspect, the present application provides a DEM-based method for quickly generating a reservoir inundation area in a mountainous river channel, comprising:

[0008] S1: obtaining or generating a digital elevation model (DEM) of the river section where the reservoir is located;

[0009] S2: obtaining the river cross-section line of the river section where the reservoir is located and performing data preprocessing;

[0010] S3: based on the backwater table data of each cross-section design water level, the construction land acquisition processing range definition specification is obtained, the corresponding backwater table of the reservoir inundation area of each cross-section of the reservoir is obtained, and data preprocessing is performed;

[0011] S4: based on the position of the river cross-section line, the river cross-section line is extended to ensure that it fully intersects with the boundaries on both sides of the river, and the entire river is divided into multiple river units based on the extended cross-section line;

[0012] S5: based on the river extension cross-section line at the upstream and downstream ends, the backwater table, and the digital elevation model (DEM) of the reservoir section, for each grid in each river unit, when the upstream and downstream water levels are inconsistent, the grid water level value is calculated one by one according to the inverse distance weighted interpolation method; when the flat section, the grid water level directly reads the cross-section water level value, and through comparison with the grid elevation value in the DEM, the grid whose water level value is higher than the elevation value is marked as a qualified inundation area grid;

[0013] S6: based on the qualified inundation area grid, the topologically closed contour boundary ordered coordinate sequence is generated by the boundary tracking algorithm, and the vector polygon is constructed, and the polygon boundary is smoothed by using the smoothing algorithm, and finally the closed surface domain vector file of the reservoir inundation area in each river unit is obtained;

[0014] S7: merging the reservoir inundation areas of multiple river units to obtain the entire reservoir inundation area.

[0015] Preferably, the method for generating the digital elevation model (DEM) of the river section where the reservoir is located in S1 comprises:

[0016] obtaining contour lines and elevation point data in a topographic map;

[0017] generating a digital elevation model (DEM) using an irregular triangle network or Kriging interpolation algorithm by using GIS software.

[0018] Preferably, the data preprocessing of the river cross-section line in S2 comprises:

[0019] Step 1: process the cross-section line into shp format vector line data;

[0020] Step 2: add attribute fields containing cross-section number and cross-section name to the cross-section line data set, and enter related information.

[0021] Preferably, the data preprocessing of the S3 backwater table includes:

[0022] Step 1: Determine the backwater level of the reservoir inundation area and the end section of the backwater according to the safety superhigh impact analysis;

[0023] Step 2: Organize the backwater table according to the standard format of section number, section name and scheme water level;

[0024] Step 3: Sort out the upstream and downstream relationship of the section and record it in the backwater table.

[0025] Preferably, the method of dividing the whole river channel into multiple river channel units based on the extended section line in S4 includes:

[0026] Step 1: Set the expansion multiple to automatically extend the section line at both ends to fully intersect with the river bank;

[0027] Step 2: Divide the whole river channel into multiple river channel units according to the extended section line and the upstream and downstream relationship.

[0028] Preferably, the step of inverse distance weighted interpolation in S5 includes:

[0029] Step 1: Determine the known water level on the upstream and downstream section lines, assuming that the point on the known section line is Qi(xi,yi) The corresponding water level value is zi;

[0030] Step 2: Determine the point to be interpolated and record its coordinates P(x,y);

[0031] Step 3: Calculate the distance di from the point to be interpolated to each known point Qi(xi,yi), and the distance formula is:

[0032] ;

[0033] Step 4: Calculate the weight wi of each known point according to the inverse distance weighted method, and the weight formula is

[0034] ;

[0035] Wherein, p is the distance weight index, and p=2; when di=0, the known point is taken as the exact value of the point to be interpolated;

[0036] Step 5: Normalize the weight, and the formula is:

[0037] , ;

[0038] Step 6: According to the normalized weight and the water level value of the known point, the water level value Z of the interpolation point P(x, y) is calculated, and the interpolation formula is:

[0039] .

[0040] Preferably, the boundary tracking algorithm in S6 includes extracting the contour boundary coordinate points of the submerged area grid, and the contour boundary coordinate points are selected from any one of the following:

[0041] (a) grid vertex;

[0042] (b) grid center point;

[0043] (c) grid edge center point;

[0044] The smoothing algorithm in S6 includes B-spline curve method and five-point smoothing method.

[0045] In a second aspect, the present application provides a DEM-based fast generation system for a mountainous river-type reservoir submerged area, which is used to implement the DEM-based fast generation method for a mountainous river-type reservoir submerged area as described above, and includes:

[0046] An acquisition unit is configured to acquire the section line, the section water level value, and the DEM elevation value;

[0047] A division unit is configured to divide the reservoir into a plurality of river channel units according to the section line;

[0048] A calculation unit is configured to calculate the water level value based on the upstream and downstream section backwater table interpolation and based on the DEM grid unit, and to calculate the difference between the water level value and the elevation value;

[0049] A fitting unit is configured to perform smoothing processing on the grid outer boundary meeting the condition to obtain a fitted reservoir submerged area;

[0050] An output unit is configured to perform merging processing on the plurality of unit data and to display and output the range result.

[0051] In a third aspect, the present application provides an electronic device, which includes:

[0052] A memory is configured to store a computer program;

[0053] A processor is configured to execute the computer program to implement the DEM-based fast generation method for a mountainous river-type reservoir submerged area as described above.

[0054] In a fourth aspect, the present application provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the DEM-based fast generation method for a mountainous river-type reservoir submerged area as described above is implemented.

[0055] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0056] This invention provides a method and system for rapidly generating inundation areas of mountainous river-type reservoirs based on high-precision DEM (Digital Elevation Model). The method includes acquiring the DEM, cross-sectional lines, and backwater tables of the reservoir river section; dividing the reservoir river section into multiple river units; calculating the water level value of each grid cell within a river unit using inverse distance weighted interpolation; determining the grid cells that meet the criteria by comparing them with the DEM grid elevation values; constructing vector polygons using ordered coordinate sequences of the contour boundaries; smoothing the polygons to obtain segmented inundation areas; and merging these segments to obtain the entire inundation area. During scheme demonstration, the method supports the second-level dynamic generation of inundation areas for multiple different backwater schemes, providing reliable spatial data support for inundation impact analysis and decision support for scheme comparison. During physical surveys, the method combines high-resolution DEM data to achieve rapid generation of inundation areas with sub-meter accuracy, providing a good data foundation for defining the required scope of physical surveys. This effectively improves the accuracy and efficiency of inundation analysis and is applicable to the generation of various mountainous river-type reservoir inundation areas. Attached Figure Description

[0057] Figure 1 This is a flowchart of the method for generating the land acquisition scope for reservoir construction according to the present invention.

[0058] Figure 2 This is a schematic diagram of the reservoir construction land acquisition scope generation system of the present invention.

[0059] Figure 3 A schematic diagram showing the results of sorting the return water meters in the flooded area.

[0060] Figure 4 A schematic diagram for dividing the river into sections for cross-section expansion.

[0061] Figure 5 This is a schematic diagram illustrating the calculation and comparison of water levels within a grid within a river channel unit.

[0062] Figure 6 This is a schematic diagram of grid boundary extraction and smoothing.

[0063] Figure 7 This is a schematic diagram of the flooding line generated from the DEM. Detailed Implementation

[0064] In order to make the technical personnel in the art better understand the technical solutions of the present application, the preferred embodiments of the present application are described below in conjunction with specific examples, but it should be understood that the drawings are only for illustrative purposes and cannot be understood as a limitation on the present patent; in order to better illustrate the present embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the actual product size; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings can be omitted. The positional relationship described in the drawings is only for illustrative purposes and cannot be understood as a limitation on the present patent.

[0065] Embodiment 1

[0066] As Figure 1 shown, it is a flow chart of a high-precision DEM-based mountainous river type reservoir inundation area rapid generation method, which includes the following steps S1-S7, specifically:

[0067] S1: Obtain or generate a digital elevation model DEM of the river section where the reservoir is located.

[0068] In a possible implementation manner, the digital elevation model DEM of the river section where the reservoir is located is obtained in S1, including:

[0069] Download or collect the DEM of the river section through various channels.

[0070] In a possible implementation manner, the method for generating the digital elevation model DEM of the river section where the reservoir is located in S1 includes:

[0071] Obtain contour lines, elevation points, etc. in the topographic map;

[0072] Generate a digital elevation model DEM by using an irregular triangle network or a Kriging interpolation algorithm for spatial interpolation by using GIS software.

[0073] In the present embodiment, a 2*2m grid digital elevation model of the area where the reservoir is located is pre-established according to the reservoir contour line. The contour line should preferably be derived from the topography in the dry season, the minimum elevation is lower than the normal water level value of the current section, and the maximum elevation is higher than the backwater level value. The digital elevation model generated in this way can clearly record the elevation data near the reservoir river, and can cover the required calculation area.

[0074] It should be noted that the higher the grid accuracy of the DEM, the higher the accuracy of the generated result, but the slower the calculation speed.

[0075] S2: Obtain the river section line of the river section where the reservoir is located, and perform data preprocessing.

[0076] In a possible implementation manner, the river section line preprocessing in S2 includes:

[0077] Step 1: Process the section line into shp format vector line data;

[0078] Step 2: Add attribute fields to the section line dataset, which should include section number, section name fields, and enter relevant information.

[0079] It should be noted that the section line coverage can include the entire main stream and the main tributaries.

[0080] S3: Based on the design water level backwater table data of each section, the water reservoir inundation area backwater table is obtained according to the construction land acquisition processing range specification, and data preprocessing is performed.

[0081] In one possible implementation, the data preprocessing of the backwater table in S3 includes the following steps:

[0082] Step 1: Determine the backwater level of the reservoir inundation area considering the influence analysis of safety surcharge, and determine the end section of backwater.

[0083] Step 2: Organize the backwater table according to the section number, section name, and scheme water level in standard format.

[0084] Step 3: Sort out the upstream and downstream relationship of the section and record it in the backwater table.

[0085] In a specific example, the organized backwater table data is as shown in Figure 3 .

[0086] It should be noted that the section number and section name should pay attention to the corresponding relationship with the section number and section name in the section line.

[0087] S4: Based on the position of the river section line, extend the section line to ensure that the section line and the boundary of the river on both sides fully intersect; based on the section line, divide the overall river into multiple river units. As shown in Figure 4 .

[0088] In one possible implementation, the method of dividing the overall river into multiple river units based on the section line in S4 includes:

[0089] Step 1: After setting the expansion section multiple, automatically extend the ends of the section line to fully intersect with the river bank to avoid the case where the section line is too short and does not intersect with the river bank;

[0090] Step 2: According to the extended section line and the upstream and downstream relationship, divide the overall river into multiple river units.

[0091] S5: Based on the river channel expansion section line at both ends, the backwater table and the reservoir river section digital elevation model DEM, for each grid in each river channel unit, when the upstream and downstream water levels are inconsistent, the water level value of the grid is calculated one by one according to the inverse distance weighted interpolation method; when the flat water section, the grid water level is directly read as the section water level value, and through comparison with the DEM grid elevation value, the reservoir inundation area grid in each river channel unit is determined according to the qualified grid.

[0092] In one possible implementation, the inverse distance weighted interpolation method step in S5 is:

[0093] Step 1: Determine the known water level on the adjacent upstream and downstream section lines, assuming that the points on the known section line are Qi(xi,yi) , the corresponding water level value is zi;

[0094] Step 2: Determine the point to be interpolated, record its coordinates P(x,y);

[0095] Step 3: Calculate the distance di of the point to be interpolated to each known point Qi(xi,yi), the distance formula is:

[0096] ;

[0097] Step 4: Calculate the weight wi of each known point according to the inverse distance weighted method, the weight formula is

[0098] ;

[0099] wherein p is the distance weight index, usually p=2, that is, the inverse of the square of the distance as the weight; when di=0, in order to avoid zero error, the known point is taken as the exact value of the point to be interpolated;

[0100] Step 5: Normalize the weight, the formula is:

[0101] , ;

[0102] Step 6: According to the normalized weight and the water level value of the known point, calculate the water level value Z of the point to be interpolated P(x,y), the interpolation formula is:

[0103] .

[0104] Further, the grid in the river channel unit is based on the DEM grid, for example, if the DEM is 1*1m, then the grid unit for calculating the water level value is also 1*1m.

[0105] It should be noted that generally from the end section (upstream) to calculate, gradually spread to the downstream section. For the reservoir flat section, the upstream and downstream section backwater level is the same, no interpolation calculation, directly take the section water level value can reduce the amount of calculation, improve the calculation efficiency.

[0106] In one possible implementation, the grid that meets the conditions is determined in S5 by the following method:

[0107] Step 1: Extract the elevation value of the DEM where the grid is located;

[0108] Step 2: Compare the calculated grid water level value with the elevation value in the DEM;

[0109] Step 3: Mark all areas where the water level value is higher than the DEM elevation value as areas that meet the conditions.

[0110] The principle of grid calculation and marking is shown in Figure 5 , where the grid is only for illustration and does not represent the actual division.

[0111] S6: Based on the grid cells that meet the submergence conditions, generate a topologically closed contour boundary ordered coordinate sequence by a boundary tracking algorithm, construct a vector polygon, and at the same time, use a smoothing algorithm to smooth the polygon boundary. Finally, get the closed surface domain vector file of the reservoir submergence area in each river channel unit.

[0112] In one possible implementation, the idea of generating a topologically closed contour boundary ordered coordinate sequence based on the grid cells that meet the submergence conditions in S6 by a boundary tracking algorithm, and constructing a vector polygon, is to directly realize the one-step construction of the submergence area vector in the grid topological space, effectively avoiding the problem of merging calculation bottleneck after grid vectorization, and avoiding the time-consuming of extracting the boundary line and then performing topological processing, which significantly improves the processing efficiency. Among them, there are three ways to extract the contour boundary coordinate points, one is the grid vertex, the smoothing processing workload is slightly larger; the second is the grid center point, the calculated submergence area is slightly smaller, but the efficiency is slightly higher; the third is the midpoint of the grid edge line.

[0113] In one possible implementation, the smoothing algorithm in S6 includes B-spline curve method and five-point smoothing method, which can effectively eliminate the jagged fluctuations. Among them, the B-spline curve method is more suitable for scenarios where precision is prioritized, and the five-point smoothing method has low computational complexity and is more suitable for scenarios where efficiency is prioritized. The smoothing processing result is shown in Figure 6 .

[0114] S7: Merge the reservoir submergence areas of multiple river channel units respectively to get the entire reservoir submergence area.

[0115] In one possible implementation, the reservoir inundation area of the adjacent multiple river channel units in S7 is merged into one complete face file, and the entire reservoir inundation area is obtained, as shown in Figure 7 .

[0116] The following is described with specific examples.

[0117] Take a certain reservoir and a certain water storage scheme as an example. A 2*2m grid DEM is generated based on contour lines, the cross-section line is arranged according to the above steps, the backwater table is preprocessed (the result is shown in Figure 3 ), and then the above data is obtained through the program page, the cross-section line is extended, and the reservoir river channel is segmented. The segmentation result is shown in Fig. 4. The boundary meeting the conditions is extracted by using interpolation calculation and comparing with the DEM elevation, and the process is shown in Figure 5 . The smoothing result is shown in Figure 6 . After merging the multi-segment data, the entire reservoir inundation area is shown in Figure 7 , and the finally generated range result is displayed in the browser window and can be exported for use.

[0118] The method of this embodiment is simple and easy to operate. Under the condition of high DEM precision, the range of different schemes of large and medium-sized reservoir areas can still be quickly generated, the range drawing time is shortened, which is conducive to the promotion of project decision-making, and provides fast data support for reservoir engineering scheme comparison and selection.

[0119] Embodiment 2

[0120] The embodiment 1 is further illustrated, Figure 2 is a structure diagram of a mountainous river channel type reservoir inundation area fast generation system based on high-precision DEM provided by the embodiment of the present application. The system comprises:

[0121] An acquisition unit is configured to acquire the cross-section line, the cross-section water level value, and the DEM elevation value.

[0122] A division unit is configured to divide the reservoir into multiple river channel units according to the cross-section line.

[0123] A calculation unit is configured to calculate the water level value based on the upstream and downstream cross-section backwater table interpolation and calculate the difference between the water level value and the elevation value based on the DEM grid unit.

[0124] A fitting unit is configured to perform smoothing processing on the grid outer boundary meeting the conditions to obtain the fitted inundation area.

[0125] An output unit is configured to perform merging processing on the multiple unit data and display and output the range result.

[0126] Embodiment 3

[0127] Further illustrated in combination with Embodiment 1, the embodiment of the present application provides an electronic device, comprising a memory and a processor;

[0128] a memory for storing a computer program;

[0129] a processor for implementing the method for quickly generating a mountainous river channel type reservoir inundation area based on high-precision DEM of Embodiment 1 when executing the computer program, wherein the computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0130] For example, the memory can include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out memory (FIFO), and / or first-in-last-out memory (FILO), etc.; the processor can be, but is not limited to, a microprocessor of STM32F105 series, an ARM (Advanced RISC Machines) processor, an X86 architecture processor, or a processor integrated with NPU (neural-network processing units).

[0131] Embodiment 4

[0132] Further illustrated in combination with Embodiment 1, the embodiment of the present application provides a computer program product, which, when executed by a processor, implements the method for quickly generating a mountainous river channel type reservoir inundation area based on high-precision DEM of Embodiment 1. The program product can execute the operations of the above steps and obtain the range result.

[0133] Embodiment 5

[0134] Further illustrated in combination with Embodiment 1, the embodiment of the present application provides a computer-readable storage medium, that is, a computer-readable storage medium having instructions stored thereon, which, when executed on a computer, execute the method for quickly generating a mountainous river channel type reservoir inundation area based on high-precision DEM of Embodiment 1. The above instructions can be implemented in the form of a software functional unit and sold or used as an independent product, which can be stored in a computer-readable storage medium.

[0135] Those skilled in the art can clearly understand the software and hardware required by each embodiment through the description of the foregoing embodiments. Based on such understanding, the technical solutions of the present application, essentially or in part, or a part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The foregoing storage medium is used to store data, which can be, but is not limited to, a floppy disk, an optical disk, a hard disk, a flash memory, an optical disk, or a USB (Universal Serial Bus) flash disk, etc. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus.

[0136] The foregoing embodiments are merely preferred technical solutions of the present application, and should not be regarded as limitations on the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A DEM-based method for quickly generating a submerged area of a mountainous river-type reservoir, characterized in that, The method comprises the following steps: S1: obtaining or generating a digital elevation model DEM of a river section where the reservoir is located; S2: obtaining a river section line of the river section where the reservoir is located, and performing data preprocessing; S3: based on the design water level backwater table data of each section, the reservoir backwater table corresponding to the reservoir inundation area of each section of the reservoir is obtained according to the construction land acquisition processing range definition specification, and data preprocessing is performed; S4: based on the position of the river section line, the river section line is extended to ensure that it fully intersects with the river bank on both sides, and the entire river is divided into multiple river units based on the extended section line; S5: based on the river extension section line at the upstream and downstream ends, the backwater table and the digital elevation model DEM of the reservoir section, for each grid in each river unit, when the upstream and downstream water levels are inconsistent, the grid water level value is calculated one by one according to the inverse distance weighted interpolation method; when the flat section, the grid water level directly reads the section water level value, by comparing with the grid elevation value in the DEM, the grid whose water level value is higher than the elevation value is marked as the inundation area grid meeting the condition; S6: based on the inundation area grid meeting the condition, the topologically closed contour boundary ordered coordinate sequence is generated by using the boundary tracking algorithm, and the vector polygon is constructed, and the polygon boundary is smoothed by using the smoothing algorithm, and finally the closed surface domain vector file of the reservoir inundation area in each river unit is obtained; S7: the reservoir inundation areas of multiple river units are merged respectively to obtain the entire reservoir inundation area.

2. The DEM-based mountainous river channel type reservoir inundation area rapid generation method according to claim 1, characterized in that, The method for generating the digital elevation model DEM of the river section where the reservoir is located in S1 comprises: Obtaining contour lines and elevation point data in a topographic map; Using GIS software to generate a digital elevation model DEM by using an irregular triangle network or a Kriging interpolation algorithm.

3. The DEM-based mountainous river channel type reservoir inundation area rapid generation method according to claim 1, characterized in that, The data preprocessing of the river section line in S2 comprises: Step 1: processing the section line into shp format vector line data; Step 2: adding attribute fields containing section number and section name to the section line data set, and entering related information.

4. The DEM-based mountain river type reservoir inundation area rapid generation method according to claim 1, characterized in that, The data preprocessing of the backwater table in S3 comprises: Step 1: considering the influence of safety superhigh, determining the backwater level of the reservoir inundation area, and determining the backwater end section; Step 2: arranging the backwater table according to the standard format of section number, section name and scheme water level; Step 3: combing the upstream and downstream relationship of the section, and recording in the backwater table.

5. The DEM-based mountainous river channel type reservoir inundation area rapid generation method according to claim 1, characterized in that, The method for dividing the entire river into multiple river units based on the extended section line in S4 comprises: Step 1: setting an expansion multiple, and automatically extending the section line at both ends to fully intersect with the river bank; Step 2: dividing the entire river into multiple river units according to the extended section line and the upstream and downstream relationship.

6. The DEM-based mountain river channel type reservoir inundation area rapid generation method according to claim 1, characterized in that, The steps of the inverse distance weighted interpolation method in S5 comprise: Step 1: Determine the known water level on the adjacent upstream and downstream cross-section lines, assuming the point on the known cross-section line is Qi(xi, yi) The corresponding water level value is zi; Step 2: determining the point to be interpolated, and recording its coordinates P(x, y); Step 3: calculating the distance di of the point to be interpolated to each known point Qi(xi, yi), and the distance formula is: ； Step 4: calculating the weight wi of each known point according to the inverse distance weighted method, and the weight formula is ； wherein p is the distance weight index, p=2; when di=0, the known point is taken as the exact value of the point to be interpolated; Step 5: normalizing the weight, and the formula is: ， ； Step 6: According to the normalized weight and the water level value of the known points, the water level value Z of the interpolation point P(x, y) is calculated, and the interpolation formula is: 。 7. The DEM-based mountainous river channel type reservoir inundation area rapid generation method according to claim 1, characterized in that, The boundary tracking algorithm in S6 includes extracting the contour boundary coordinate points of the submerged area grid, and the contour boundary coordinate points are selected from any one of the following: (a) Grid vertex; (b) Grid center point; (c) Grid edge center point; The smoothing algorithm in S6 includes B-spline curve method and five-point smoothing method.

8. A DEM-based mountainous river channel type reservoir inundation area rapid generation system, characterized in that, The method for implementing the DEM-based rapid generation of mountainous river-type reservoir submerged area according to any one of claims 1-7 comprises: An acquisition unit is configured to acquire a section line, a section water level value, and a DEM elevation value; A division unit is configured to divide the reservoir into a plurality of river channel units according to the section line; A calculation unit is configured to calculate the water level value based on the upstream and downstream section backwater table interpolation and the DEM grid unit, and to calculate the difference between the water level value and the elevation value; A fitting unit is configured to perform smoothing processing on the grid outer boundary that meets the condition to obtain a fitted reservoir submerged area; An output unit is configured to perform merging processing on the plurality of unit data and to display and output the range result.

9. An electronic device, comprising: It comprises: A memory is configured to store a computer program; A processor is configured to execute the computer program to implement the DEM-based rapid generation of mountainous river-type reservoir submerged area according to any one of claims 1-7.

10. A computer program product, characterised in that, It comprises a computer program, which, when executed by a processor, implements the DEM-based rapid generation of mountainous river-type reservoir submerged area according to any one of claims 1-7.

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