A method for simulating urban flooding based on oblique photography and finite volume method

Abstract

The present invention provides an urban waterlogging simulation method based on oblique photography and the finite volume method, and relates to the technical field of urban waterlogging simulation. The method comprises: processing a three-dimensional oblique photography model of a study area to obtain terrain data, extracting urban waterlogging model parameters therefrom, and constructing a drainage network and catchment area model; discretizing the constructed one-dimensional drainage network using the finite volume method, establishing a one-dimensional drainage network hydrodynamic model, and using the runoff curve number method to simulate the drainage network's runoff generation, confluence process, and transmission state; spatially discretizing the constructed two-dimensional terrain data based on the finite volume method, establishing a two-dimensional surface runoff model, and simulating the movement of rainwater on the surface; coupling the one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model to obtain an urban waterlogging model; and visually displaying the simulation results based on the oblique photography three-dimensional model. The present invention can improve the accuracy of simulation results and intuitively display the evolution of the urban waterlogging process.

Description

Technical Field

[0001] The present invention relates to the technical field of urban waterlogging simulation, and in particular to an urban waterlogging simulation method based on oblique photography and a finite volume method. Background Art

[0002] By providing simulation results, the urban waterlogging model can predict waterlogging points and water levels in advance, helping people travel on rainy days. At the same time, it can intuitively understand the city’s flood control weaknesses and facilitate the deployment of waterlogging control decisions.

[0003] Currently, most urban flooding models are based on satellite imagery, resulting in relatively low accuracy. This makes it difficult to simulate rainfall and waterlogging accurately enough for cities. Furthermore, the simulation results lack 3D visualization, making it difficult to visually visualize the evolution of urban flooding. Therefore, there is an urgent need for more accurate terrain files to construct flooding models that meet urban flood control requirements. Simulation results should be able to visualize the evolution of urban flooding in 3D, providing a more accurate and intuitive picture of the changes in urban waterlogging after rainfall. Summary of the Invention

[0004] In response to the above problems, the purpose of the present invention is to provide an urban waterlogging simulation method based on oblique photography and the finite volume method. By obtaining high-precision terrain data through oblique photography and constructing an urban waterlogging model based on the finite volume method, the accuracy of the simulation results can be greatly improved. At the same time, the oblique photography model can be used for three-dimensional visualization of the simulation results, which can more intuitively display the evolution of urban waterlogging after rainfall.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In one aspect, a method for simulating urban flooding based on oblique photography and a finite volume method is provided, the method comprising the following steps:

[0007] Step 1: Process the oblique photography 3D model of the study area to obtain terrain data, including digital surface model (DSM) data, digital true orthogonal image (TDOM) data, and digital elevation model (DEM) data. Parameters for the urban waterlogging model are extracted from the terrain data to construct a drainage network and catchment area model.

[0008] Step 2: The one-dimensional drainage network constructed by oblique photography is discretized using the finite volume method based on mass and momentum balance, and a one-dimensional drainage network hydrodynamic model is established. The runoff curve number method is used to simulate the flow generation, confluence process, and transmission status of the drainage network.

[0009] Step 3: Based on the finite volume method, the two-dimensional terrain data obtained by oblique photography is spatially discretized to establish a two-dimensional surface runoff model to simulate the movement of rainwater on the surface;

[0010] Step 4: Couple the one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model to obtain an urban waterlogging model capable of full-time bidirectional data exchange and iterative calculation;

[0011] Step 5: Visualize the simulation results based on the oblique photography 3D model.

[0012] Optionally, the step 1 specifically includes:

[0013] The digital surface model (DSM) data is obtained by densely matching the oblique photography 3D model, which is used to build a 2D surface model.

[0014] Perform true orthogonal image correction on the oblique photography 3D model to obtain digital true orthogonal image TDOM data, which is used to obtain land use distribution data, thereby extracting modeling parameters and constructing a watershed model;

[0015] The oblique photography three-dimensional model elevation points were collected to obtain the digital elevation model (DEM) data, which was used to obtain the flow direction data. The flow direction was then considered based on the Thiessen polygon method, and the study area was divided into multiple sub-catchments. The terrain data partitions were processed to obtain the modeling parameters of the drainage network and each sub-catchment.

[0016] Optionally, the step 2 specifically includes:

[0017] The finite volume method based on mass and momentum balance is used to discretize the non-overlapping volume of the constructed one-dimensional drainage network and establish a one-dimensional drainage network hydrodynamic model.

[0018] The infiltration rate was calculated using the runoff curve number method to simulate the runoff generation and confluence process of the drainage network. The process of converting the runoff generated by rainfall in each sub-catchment area into water that can be discharged to the outlet through the confluence of the surface and pipes was obtained, as well as the transmission status of rainwater in the absence of other water flows in the pipe network.

[0019] Optionally, the step three specifically includes:

[0020] The two-dimensional terrain data constructed by oblique photography were spatially discretized based on the finite volume method to establish a two-dimensional surface runoff model.

[0021] Considering advection, pressure and friction, the two-dimensional Saint-Venant equation is solved by controlling the volume to calculate the state variables and surface fluxes on each grid cell, simulating the movement of rainwater on the surface.

[0022] Optionally, the step 4 specifically includes:

[0023] The one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model are subjected to bidirectional data exchange and iterative calculation in each time period to obtain the urban waterlogging simulation results and establish an urban waterlogging model.

[0024] Optionally, the step five specifically includes:

[0025] The simulation results are made consistent with the coordinates of the oblique photography 3D model, and the simulation results are visualized based on the oblique photography 3D model, in which the simulated accumulated water is adjusted to a predetermined color, thereby intuitively displaying the evolution process of urban waterlogging over the entire period.

[0026] In another aspect, an urban flooding simulation system based on oblique photography and the finite volume method is provided for implementing any of the above methods, the system comprising:

[0027] A data processing module is used to process the oblique photography 3D model of the study area to obtain terrain data, including digital surface model (DSM) data, digital true orthogonal image (TDOM) data, and digital elevation model (DEM) data, and to extract urban waterlogging model parameters from the terrain data to construct a drainage network and catchment area model;

[0028] The first modeling module is used to discretize the one-dimensional drainage network constructed by oblique photography using the finite volume method based on mass and momentum balance, establish a one-dimensional drainage network hydrodynamic model, and use the runoff curve number method to simulate the drainage network flow generation, confluence process and transmission status;

[0029] The second modeling module is used to spatially discretize the two-dimensional terrain data obtained by oblique photography based on the finite volume method, establish a two-dimensional surface runoff model, and simulate the movement of rainwater on the surface;

[0030] A coupling module is used to couple a one-dimensional drainage network hydrodynamic model with a two-dimensional surface runoff model to obtain an urban waterlogging model capable of full-time bidirectional data exchange and iterative calculations;

[0031] The visualization module is used to visualize the simulation results based on the oblique photography 3D model.

[0032] In another aspect, an electronic device is provided, comprising:

[0033] processor;

[0034] A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are loaded and executed by the processor, the steps of the urban waterlogging simulation method described above are implemented.

[0035] On the other hand, a computer-readable storage medium is provided, in which program code is stored. The program code can be called by a processor to execute the steps of the urban waterlogging simulation method as described above.

[0036] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0037] In an embodiment of the present invention, terrain data such as DSM, TDOM, and DEM are obtained by processing the three-dimensional model of the oblique photography of the study area, and more accurate urban waterlogging model parameters are extracted therefrom to construct a drainage network and catchment area model; the high-precision one-dimensional drainage network constructed by the oblique photography is discretized using the finite volume method based on mass and momentum balance to establish a one-dimensional drainage network hydrodynamic model, and the runoff curve number method is used to simulate the flow generation, convergence process, and transmission state of the drainage network; the high-precision two-dimensional terrain data obtained by the oblique photography is spatially discretized based on the finite volume method to construct a two-dimensional surface runoff model to simulate the movement of rainwater on the surface; the one-dimensional and two-dimensional models are coupled to obtain an urban waterlogging model that can perform two-way data exchange and iterative calculations throughout the entire time period; the simulation results are visualized based on the three-dimensional model of the oblique photography to intuitively display the evolution process of urban waterlogging throughout the entire time period. The present invention obtains high-precision terrain data through oblique photography and constructs an urban waterlogging model based on the finite volume method, which can greatly improve the accuracy of simulation results. The simulation results are obtained by coupling the drainage network hydrodynamic model and the surface runoff model. At the same time, the oblique photography model can be used for three-dimensional visualization of the simulation results, which can more intuitively show the evolution of the urban waterlogging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 This is a flow chart of a method for simulating urban waterlogging based on oblique photography and the finite volume method, provided by an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of a three-dimensional model of an oblique photography of a study area provided by an embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of terrain data obtained through processing according to an embodiment of the present invention; Figure 3 (a) is the digital surface model (DSM) data. Figure 3 (b) is the true digital orthogonal image (TDOM) data. Figure 3 Middle (c) is the digital elevation model (DEM) data;

[0042] Figure 4 This is a schematic diagram of urban waterlogging modeling data obtained through processing according to an embodiment of the present invention; Figure 4 (a) in the middle is the catchment model data; Figure 4(b) in the middle is the drainage network data; Figure 4 (c) in the middle is the land use distribution data;

[0043] Figure 5 2. This is a schematic diagram of a time series of rainstorm intensity obtained by processing according to an embodiment of the present invention;

[0044] Figure 6 2. It is a schematic diagram of the urban waterlogging simulation result obtained by processing according to an embodiment of the present invention;

[0045] Figure 7 This is a three-dimensional visualization of the urban waterlogging simulation results obtained by processing an embodiment of the present invention. DETAILED DESCRIPTION

[0046] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" in the present invention should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner.

[0048] The embodiment of the present invention provides a method for simulating urban flooding based on oblique photography and finite volume method. Figure 1 As shown, the processing flow of the method may include the following steps:

[0049] Step 1: Process the oblique photography 3D model of the study area to obtain terrain data, including digital surface model (DSM) data, digital true orthogonal image (TDOM) data, and digital elevation model (DEM) data. Extract urban waterlogging model parameters from the terrain data and construct a drainage network and catchment area model.

[0050] In this step, the oblique photography 3D model of the study area is as follows Figure 2 The flood control and drainage data of the study area are urban rainwater engineering planning data, including basic data such as rainstorm intensity formula, drainage network laying conditions and pipeline parameters, and underlying surface parameters. The terrain data obtained by processing the oblique photography 3D model of the study area specifically includes:

[0051] The digital surface model DSM data is obtained by dense matching processing of the oblique photography 3D model, such as Figure 3As shown in (a), it is used to build a two-dimensional surface model;

[0052] Perform true orthogonal image correction on the oblique photography 3D model to obtain digital true orthogonal image TDOM data, such as Figure 3 As shown in (b), the surface model without building obstructions is used to obtain more accurate land use distribution data, thereby extracting modeling parameters and constructing a watershed model.

[0053] Collect oblique photography 3D model elevation points to obtain digital elevation model DEM data, such as Figure 3 Figure (c) is used to obtain data such as flow direction. Based on the Thiessen polygon method, the study area is divided into multiple subcatchments, and the terrain data is processed to obtain modeling parameters for the drainage network and each subcatchment. Specific parameters include network node elevation data, drainage network slope, pipe length, catchment area, and imperviousness.

[0054] In the embodiment of the present invention, the urban waterlogging modeling data obtained by processing is as follows: Figure 4 As shown, Figure 4 (a) in the middle is the catchment model data; Figure 4 (b) in the middle is the drainage network data; Figure 4 (c) in the middle is the land use distribution data. Figure 5 1 is a schematic diagram of a time series of rainstorm intensity obtained by processing an embodiment of the present invention.

[0055] Step 2: Use the finite volume method based on mass and momentum balance to discretize the one-dimensional drainage network constructed by oblique photography, establish a one-dimensional drainage network hydrodynamic model, and use the runoff curve number method to simulate the drainage network flow generation, confluence process and transmission status.

[0056] In this step, the finite volume method based on mass and momentum balance is used to discretize the non-overlapping volume of the constructed high-precision one-dimensional drainage network and establish a one-dimensional drainage network hydrodynamic model.

[0057] The differential form of the fluid mass conservation equation for one-dimensional flow is as follows:

[0058] (1)

[0059] Where A represents the cross-sectional flow area, u represents the flow velocity, x represents the spatial coordinate, and t represents time.

[0060] The mass conservation equation is discretized based on the finite volume method and is in the form:

[0061] (2)

[0062] Here, i represents the grid unit and n represents the time step.

[0063] The momentum equation describes the change in fluid momentum, including the effects of pressure gradient and friction, and its one-dimensional form is:

[0064] (3)

[0065] Where P is pressure and f is friction.

[0066] The momentum equation is discretized based on the finite volume method and is in the form:

[0067] (4)

[0068] Among them, A i is the cross-sectional area of grid cell i, f i is the friction force at grid cell i.

[0069] By solving the discrete forms of mass and momentum balance equations, the hydraulic parameters of the one-dimensional drainage network (such as flow velocity and water depth) can be simulated.

[0070] The infiltration rate was calculated using the runoff curve number method to simulate the runoff generation and confluence process of the one-dimensional drainage network. The process of converting the runoff generated by rainfall in each sub-catchment area into water that can be discharged to the outlet through the confluence of the surface and pipes was obtained, as well as the transmission status of rainwater in the absence of other water flows in the pipe network.

[0071] The surface runoff calculation formula is shown in formula (5), which is based on the principle of water balance in the basin and a large amount of measured data, and is derived by statistical induction:

[0072] (5)

[0073] Where Q is the surface runoff, p is the rainfall, S is the infiltration, and I_a is the pre-runoff loss, taking into account all losses before runoff. I_a is calculated using the empirical formula (6):

[0074] (6)

[0075] Where CN is an empirical coefficient used to reflect the runoff capacity of the regional underlying surface unit and is closely related to underlying surface factors such as land use type, soil type, and previous soil moisture level.

[0076] Step 3: Based on the finite volume method, the two-dimensional terrain data obtained by oblique photography are spatially discretized, and a two-dimensional surface runoff model is established. The two-dimensional Saint-Venant equation is solved by controlling the volume to calculate the state variables and surface flux on each grid cell, simulating the movement of rainwater on the surface.

[0077] In this step, the high-precision two-dimensional terrain data constructed by oblique photography are spatially discretized based on the finite volume method to establish a two-dimensional surface runoff model. The two-dimensional Saint-Venant equations (Equations (7) and (8)) are solved by controlling the volume to calculate the state variables and surface fluxes on each grid cell. It is necessary to consider that the X and Y cells have fluxes in the x and y directions, and advection, pressure, and friction are taken into account to simulate the movement of rainwater on the surface.

[0078] (7)

[0079] (8)

[0080] Where X and Y represent the units in the x and y directions respectively, g is the acceleration of gravity, A is the cross-sectional flow area, Q is the surface runoff, H is the hydraulic head, S fx represents the hydraulic slope in the x direction, S fy Represents the hydraulic slope in the y direction.

[0081] Step 4: Couple the one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model to obtain an urban waterlogging model that can perform full-time bidirectional data exchange and iterative calculations.

[0082] In this step, the one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model are bidirectionally exchanged and iteratively calculated in each time period to obtain the urban waterlogging simulation results, such as Figure 6 As shown in Figure 2, an urban flooding model is established.

[0083] The one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model are synchronized in time and exchanged in flow at the end of each time step. The overflow volume of the overflow node in the one-dimensional drainage network hydrodynamic model is assigned as the flow input to the overflow node in the corresponding cell of the two-dimensional surface runoff model to realize the coupled calculation of the one-dimensional and two-dimensional models.

[0084] Step 5: Visualize the simulation results based on the oblique photography 3D model.

[0085] In this step, the simulation results are made consistent with the coordinates of the oblique photography 3D model, and the simulation results are visualized based on the oblique photography 3D model, where the simulated waterlogging is adjusted to a predetermined color, such as red or other obvious colors, so as to intuitively show the evolution process of urban flooding over the entire period. Figure 7 shown.

[0086] In an embodiment of the present invention, high-precision terrain data is obtained through oblique photography, and an urban waterlogging model is constructed based on the finite volume method, which can greatly improve the accuracy of the simulation results. The drainage network hydrodynamic model and the surface runoff model are coupled to obtain simulation results. At the same time, the oblique photography model can be used for three-dimensional visualization of the simulation results, which can more intuitively show the evolution of the urban waterlogging process.

[0087] Accordingly, an embodiment of the present invention further provides an urban waterlogging simulation system based on oblique photography and the finite volume method, for implementing the above-mentioned urban waterlogging simulation method based on oblique photography and the finite volume method. The system comprises:

[0088] A data processing module is used to process the oblique photography 3D model of the study area to obtain terrain data, including digital surface model (DSM) data, digital true orthogonal image (TDOM) data, and digital elevation model (DEM) data, and to extract urban waterlogging model parameters from the terrain data to construct a drainage network and catchment area model;

[0089] The first modeling module is used to discretize the one-dimensional drainage network constructed by oblique photography using the finite volume method based on mass and momentum balance, establish a one-dimensional drainage network hydrodynamic model, and use the runoff curve number method to simulate the drainage network flow generation, confluence process and transmission status;

[0090] The second modeling module is used to spatially discretize the two-dimensional terrain data obtained by oblique photography based on the finite volume method, establish a two-dimensional surface runoff model, and simulate the movement of rainwater on the surface;

[0091] A coupling module is used to couple a one-dimensional drainage network hydrodynamic model with a two-dimensional surface runoff model to obtain an urban waterlogging model capable of full-time bidirectional data exchange and iterative calculations;

[0092] The visualization module is used to visualize the simulation results based on the oblique photography 3D model.

[0093] The system of this embodiment can be used to perform Figure 1 The technical solution of the method embodiment shown has similar implementation principles and technical effects, which will not be repeated here.

[0094] In an exemplary embodiment, the present invention further provides an electronic device, comprising:

[0095] processor;

[0096] A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are loaded and executed by the processor, the steps of the urban waterlogging simulation method described above are implemented.

[0097] In an exemplary embodiment, the present invention further provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement the steps of the urban flooding simulation method described above. For example, the computer-readable storage medium may be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, or optical data storage device.

[0098] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or terminal device that includes a series of elements includes not only those elements but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or terminal device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0099] References in the specification to "one embodiment," "an embodiment," "exemplary embodiments," "some embodiments," etc. indicate that the described embodiments may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes that particular feature, structure, or characteristic. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of persons skilled in the relevant art to implement that feature, structure, or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0100] It should be understood that the term "and / or" as used herein simply describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the related objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0101] In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0102] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0103] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of the device or unit, which can be electrical, mechanical or other forms.

[0104] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0105] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0106] If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media that can store program code, such as USB flash drives, mobile hard drives, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical disks.

[0107] The present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention. To provide a thorough understanding of the present invention, specific details are described in detail below in connection with the preferred embodiments of the present invention, but those skilled in the art will be able to fully understand the present invention without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of the present invention, well-known methods, processes, procedures, components, and circuits have not been described in detail.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for simulating urban flooding based on oblique photography and finite volume method, characterized in that: The following steps are involved: Step 1: Process the oblique photography 3D model of the study area to obtain terrain data, including digital surface model (DSM) data, digital true orthogonal image (TDOM) data, and digital elevation model (DEM) data. Parameters of the urban waterlogging model are extracted from the terrain data to construct a drainage network and catchment area model. Step 2: Use the finite volume method based on mass and momentum balance to discretize the non-overlapping volumes of the one-dimensional drainage network constructed by oblique photography, and establish a one-dimensional drainage network hydrodynamic model. Use the runoff curve number method to calculate the infiltration rate, simulate the flow generation and confluence process of the drainage network, and understand the process by which runoff generated by rainfall in each sub-catchment area is converted through the confluence of surface and pipe flow to discharge to the outlet, as well as the transmission status of rainwater in the absence of other water flows in the pipe network. Step 3: Spatially discretize the two-dimensional terrain data obtained from oblique photography using the finite volume method to establish a two-dimensional surface runoff model. Considering advection, pressure, and friction, the two-dimensional Saint-Venant equation is solved by controlling the volume to calculate the state variables and surface fluxes at each grid cell, simulating the movement of rainwater on the surface. Step 4: Couple the one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model to obtain an urban waterlogging model capable of full-time bidirectional data exchange and iterative calculation; Step 5: Visualize the simulation results based on the oblique photography 3D model.

2. The urban flooding simulation method based on oblique photography and finite volume method according to claim 1 is characterized in that: The step 1 specifically includes: The digital surface model (DSM) data is obtained by densely matching the oblique photography 3D model, which is used to build a 2D surface model. Perform true orthogonal image correction on the oblique photography 3D model to obtain digital true orthogonal image TDOM data, which is used to obtain land use distribution data, thereby extracting modeling parameters and constructing a watershed model; The oblique photography three-dimensional model elevation points were collected to obtain the digital elevation model (DEM) data, which was used to obtain the flow direction data. The flow direction was then considered based on the Thiessen polygon method, and the study area was divided into multiple sub-catchments. The terrain data partitions were processed to obtain the modeling parameters of the drainage network and each sub-catchment.

3. The urban flooding simulation method based on oblique photography and finite volume method according to claim 1 is characterized in that: The step 4 specifically includes: The one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model are subjected to bidirectional data exchange and iterative calculation in each time period to obtain the urban waterlogging simulation results and establish an urban waterlogging model.

4. The urban flooding simulation method based on oblique photography and finite volume method according to claim 1 is characterized in that: The step five specifically includes: The simulation results are made consistent with the coordinates of the oblique photography 3D model, and the simulation results are visualized based on the oblique photography 3D model, in which the simulated accumulated water is adjusted to a predetermined color, thereby intuitively displaying the evolution process of urban waterlogging over the entire period.

5. An urban flooding simulation system based on oblique photography and finite volume method, the system being used to implement the method according to any one of claims 1 to 4, characterized in that: The system comprises: A data processing module is used to process the oblique photography 3D model of the study area to obtain terrain data, including digital surface model (DSM) data, digital true orthogonal image (TDOM) data, and digital elevation model (DEM) data, and to extract urban waterlogging model parameters from the terrain data to construct a drainage network and catchment area model; The first modeling module is used to discretize the one-dimensional drainage network constructed by oblique photography using the finite volume method based on mass and momentum balance, establish a one-dimensional drainage network hydrodynamic model, and use the runoff curve number method to simulate the drainage network flow generation, confluence process and transmission status; The second modeling module is used to spatially discretize the two-dimensional terrain data obtained by oblique photography based on the finite volume method, establish a two-dimensional surface runoff model, and simulate the movement of rainwater on the surface; A coupling module is used to couple a one-dimensional drainage network hydrodynamic model with a two-dimensional surface runoff model to obtain an urban waterlogging model capable of full-time bidirectional data exchange and iterative calculations; The visualization module is used to visualize the simulation results based on the oblique photography 3D model.

6. An electronic device, characterized in that: The electronic device comprises: processor; A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are loaded and executed by the processor, the method according to any one of claims 1 to 4 is implemented.

7. A computer-readable storage medium, characterized in that The computer-readable storage medium stores program code, which can be called by a processor to execute the method according to any one of claims 1 to 4.

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