Urban inland inundation simulation method based on oblique photography and finite volume method

Abstract

The invention provides an urban inland inundation simulation method based on oblique photography and a finite volume method, and relates to the technical field of urban inland inundation simulation. The method comprises the following steps: processing an oblique photography three-dimensional model of a research area to obtain topographic data, extracting urban inland inundation model parameters from the topographic data, and constructing a drainage pipe network and catchment area model; discretizing the constructed one-dimensional drainage pipe network by utilizing a finite volume method, establishing a one-dimensional drainage pipe network hydrodynamic model, and simulating by adopting a runoff curve number method to obtain the runoff production and confluence process and the transmission state of the drainage pipe network; performing spatial discretization on the constructed two-dimensional topographic data based on a finite volume method, establishing a two-dimensional surface runoff model, and simulating a motion state of rainwater on the surface; coupling the one-dimensional drainage pipe network hydrodynamic model and the two-dimensional surface runoff model to obtain an urban waterlogging model; and performing visual display on a simulation result based on the oblique photography three-dimensional model. The simulation result precision can be improved, and the evolution of the urban inland inundation process can be visually displayed.

Description

Technical Field

[0001] The 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. It can also intuitively understand the weak points of urban flood control and facilitate the deployment of waterlogging control decisions.

[0003] At present, most urban waterlogging models are built based on satellite images, and the model accuracy is relatively low, which makes it difficult to meet the rainfall and waterlogging simulation accuracy required by the city. In addition, the simulation results lack three-dimensional display, and the evolution of urban waterlogging cannot be obtained intuitively. Therefore, there is an urgent need for higher-precision terrain files to build waterlogging models that meet the requirements of urban flood control, and the simulation results can display the evolution of urban waterlogging in three dimensions, and more accurately and intuitively show the changes in urban waterlogging after rainfall. Summary of the invention

[0004] In view of 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 acquiring 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] On the one hand, a method for simulating urban waterlogging based on oblique photography and 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, and extract urban waterlogging model parameters 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, a one-dimensional drainage network hydrodynamic model is established, and the runoff curve number method is used to simulate the flow generation, confluence process and transmission state 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 two-way 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 are collected to obtain the digital elevation model DEM data, which is used to obtain the flow direction data. The flow direction is then considered based on the Thiessen polygon method, and the study area is divided into multiple sub-catchment areas. The terrain data partitions are processed to obtain the drainage network and the modeling parameters of each sub-catchment area.

[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 the hydrodynamic model of the one-dimensional drainage network is established.

[0018] The infiltration rate is calculated using the runoff curve number method to simulate the flow 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, as well as the transmission status of rainwater in the absence of other water flows in the pipe network, is obtained.

[0019] Optionally, the step three specifically includes:

[0020] Based on the finite volume method, the two-dimensional terrain data constructed by oblique photography is spatially discretized 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 flux 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 waterlogging is adjusted to a predetermined color, thereby intuitively displaying the evolution of urban waterlogging over the entire period of time.

[0026] On the other hand, a system for simulating urban waterlogging based on oblique photography and 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 three-dimensional model of the study area to obtain terrain data, the terrain data includes digital surface model DSM data, digital true orthogonal image TDOM data, digital elevation model DEM data, and 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 state;

[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] The coupling module is used to 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 two-way data exchange and iterative calculation;

[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, the electronic device 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 as described above are implemented.

[0035] On the other hand, a computer-readable storage medium is provided, in which a 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 oblique photography of the study area, and higher-precision urban waterlogging model parameters are extracted therefrom to construct a drainage network and a catchment area model; the high-precision one-dimensional drainage network constructed by 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, confluence process and transmission state of the drainage network; based on the finite volume method, the high-precision two-dimensional terrain data obtained by oblique photography is spatially discretized 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 full-time bidirectional data exchange and iterative calculation; the simulation results are visualized based on the three-dimensional model of oblique photography to intuitively display the evolution process of urban waterlogging over the entire period of time. 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 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 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 is a flow chart of a method for simulating urban waterlogging based on oblique photography and finite volume method provided by an embodiment of the present invention;

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

[0041] Figure 3 is a schematic diagram of terrain data obtained by processing in 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 (c) is the digital elevation model (DEM) data;

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

[0043] Figure 5 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 is a schematic diagram of the urban waterlogging simulation result obtained by processing according to an embodiment of the present invention;

[0045] Figure 7 It is a three-dimensional visualization diagram of the urban waterlogging simulation result obtained by processing according to the embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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 explanations. Any embodiment or design described as "exemplary" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the word "exemplary" is used to present concepts in a specific way.

[0048] The embodiment of the present invention provides a method for simulating urban waterlogging 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, which includes digital surface model DSM data, digital true orthogonal image TDOM data, and digital elevation model DEM data, and extract urban waterlogging model parameters from the terrain data to build 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 the urban rainwater engineering planning data, including the rainstorm intensity formula, drainage network laying conditions and pipeline parameters, underlying surface parameters and other basic data. The terrain data obtained by processing the three-dimensional model of oblique photography in the study area specifically include:

[0051] The digital surface model DSM data is obtained by densely matching the oblique photography 3D model. Figure 3As shown in (a), it is used to establish a two-dimensional surface model;

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

[0053] Collect oblique photography 3D model elevation points to obtain digital elevation model DEM data, such as Figure 3 As shown in (c), it is used to obtain data such as flow direction; then based on the Thiessen polygon method, the flow direction is considered, the study area is divided into multiple sub-catchments, and the terrain data is processed to obtain the drainage network and the modeling parameters of each sub-catchment. Specific parameters include network node elevation data, drainage network slope, pipe length, catchment area, impermeability, etc.

[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) is the catchment model data; Figure 4 (b) is the drainage network data; Figure 4 (c) is the land use distribution data. Figure 5 Schematic diagram of the rainstorm intensity time series obtained by processing according to 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 a one-dimensional drainage network hydrodynamic model is established.

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

[0058] (1)

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

[0060] The mass conservation equation is discretized based on the finite volume method into the following 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] Among them, 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 in grid cell i.

[0069] By solving the discrete form 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 is 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, as well as the transmission state of rainwater in the absence of other water flows in the pipe network, is obtained.

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

[0072] (5)

[0073] In the formula, Q is the surface runoff, p is the rainfall, S is the infiltration, and I_a is the pre-loss amount, which takes 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 unit, 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 (Eqs. (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 gravitational acceleration, A is the cross-sectional flow area, Q is the surface runoff, H is the hydraulic head, and 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 two-way data exchange and iterative calculation.

[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, an urban waterlogging model is established.

[0083] The one-dimensional drainage network hydrodynamic model and the two-dimensional surface runoff model perform time synchronization and flow exchange 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, wherein the simulated waterlogging is adjusted to a predetermined color, such as red or other obvious colors, so as to intuitively display the evolution process of urban waterlogging over the entire period, such as 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 the 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 finite volume method, which is used to implement the above-mentioned urban waterlogging simulation method based on oblique photography and finite volume method, and the system includes:

[0088] A data processing module is used to process the oblique photography three-dimensional model of the study area to obtain terrain data, the terrain data includes digital surface model DSM data, digital true orthogonal image TDOM data, digital elevation model DEM data, and 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 state;

[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] The coupling module is used to 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 two-way data exchange and iterative calculation;

[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 execute 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, the 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 as described above are implemented.

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

[0098] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including 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 restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

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

[0100] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship, but it may also indicate an "and / or" relationship. Please refer to the context for specific understanding.

[0101] In the present invention, "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 items 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 multiple.

[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 only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, 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 interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

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

[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 in the form of 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 part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0107] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not 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 principle of the present invention should be included in the protection scope 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, and extract urban waterlogging model parameters from the terrain data to construct a drainage network and catchment area model; Step 2: The one-dimensional drainage network constructed by oblique photography is discretized using the finite volume method based on mass and momentum balance, a one-dimensional drainage network hydrodynamic model is established, and the runoff curve number method is used to simulate the flow generation, confluence process and transmission state of the drainage network; 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; 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 two-way 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 are collected to obtain the digital elevation model DEM data, which is used to obtain the flow direction data. The flow direction is then considered based on the Thiessen polygon method, and the study area is divided into multiple sub-catchment areas. The terrain data partitions are processed to obtain the drainage network and the modeling parameters of each sub-catchment area.

3. The urban flooding simulation method based on oblique photography and finite volume method according to claim 1 is characterized in that: The step 2 specifically includes: 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 the hydrodynamic model of the one-dimensional drainage network is established. The infiltration rate is calculated using the runoff curve number method to simulate the flow 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, as well as the transmission status of rainwater in the absence of other water flows in the pipe network, is obtained.

4. The urban flooding simulation method based on oblique photography and finite volume method according to claim 1 is characterized in that: The step three specifically includes: Based on the finite volume method, the two-dimensional terrain data constructed by oblique photography is spatially discretized 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 flux on each grid cell, simulating the movement of rainwater on the surface.

5. 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.

6. 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 waterlogging is adjusted to a predetermined color, thereby intuitively displaying the evolution of urban waterlogging over the entire period of time.

7. 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 6, characterized in that: The system comprises: A data processing module is used to process the oblique photography three-dimensional model of the study area to obtain terrain data, the terrain data includes digital surface model DSM data, digital true orthogonal image TDOM data, digital elevation model DEM data, and 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 state; 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; The coupling module is used to 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 two-way data exchange and iterative calculation; The visualization module is used to visualize the simulation results based on the oblique photography 3D model.

8. 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 6 is implemented.

9. 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 6.

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