Visualization processing method of urban drainage system based on pipe network generalization model

Abstract

The present invention relates to a method for visualizing an urban drainage system based on a pipe network generalization model. The method constructs a drainage system framework model that expresses the overall spatial distribution of the entire urban drainage system, a drainage system generalization model that reflects the upstream and downstream topological relationships of sewage treatment plants and drainage pumping stations and the relationship between connected trunk pipes and main pipes, and a drainage system topology model that can reflect the layout of the underground sewage system and the flow direction of sewage in the city. Then, based on the drainage system topology model, the method uses two types of geometric forms, points and lines, to schematically and physically express the pipe network relationships in the obtained drainage system topology model, thereby realizing a visual display of the urban underground drainage system, thereby effectively solving the problem of "invisible" and "unusable" urban underground pipe networks, truly and comprehensively reflecting the overall topological relationship and global operating status of the urban underground drainage system, and meeting the spatial display and analysis application needs of various industries and departments in the construction of new smart cities for underground pipeline data.

Description

Technical Field

[0001] The present invention relates to the field of underground pipe network data processing, and in particular to a visualization processing method for an urban drainage system based on a pipe network generalization model. Background Art

[0002] The urban underground drainage system is an important part of the urban pipeline system and is of great significance to ensuring the normal operation of the city.

[0003] In the existing urban underground drainage system management process, there has long been a phenomenon of multiple departments (such as pipeline design units, construction units, maintenance units, natural resources units, water conservancy units and housing and construction units, etc.) managing the drainage system separately, resulting in serious data loss in the urban underground pipeline system and reducing the overall digital management level of the urban underground drainage system.

[0004] In addition, most pipeline data in existing urban underground drainage systems are still in paper form or in the form of CAD electronic documents for individual completion and maintenance projects. They can only simply display the pipeline information of a local area of ​​the city's underground drainage system, and cannot truly and comprehensively reflect the overall topological relationship and global operating status of the urban underground drainage system, which is not conducive to the management of the urban underground drainage system. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a method for visualizing urban drainage systems based on a generalized pipe network model, in response to the above-mentioned existing technologies. This method, based on a generalized pipe network model, constructs a hierarchical generalized model of the urban drainage network, enabling a schematic visualization of the urban underground drainage system.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: a method for visualizing an urban drainage system based on a pipe network generalization model, characterized by comprising the following steps:

[0007] Step 1: Construct a drainage system framework model that represents the overall spatial distribution of the entire urban drainage system. This model uses the sewage treatment plant as the primary node and the pumping stations that deliver sewage to the sewage treatment plant as the skeleton nodes. The lines between the sewage treatment plant and each pumping station, and between pumping stations, are used to schematically outline the drainage system's line framework, thereby characterizing the sewage flow relationship characteristics within the entire system.

[0008] Step 2: Based on the constructed drainage system framework model, a generalized drainage system model is constructed to reflect the upstream and downstream topological relationships of sewage treatment plants and drainage pumping stations, as well as the interconnected trunk pipelines and main pipe relationships. This generalized drainage system model represents the sewage transportation route within the entire urban underground drainage system.

[0009] Step 3: Simplify the constructed drainage system generalization model and retain all major pipelines that can reflect the layout of the city's underground sewage system and the direction of sewage flow. The topological relationship formed by all the retained major pipelines is used as the drainage system topology model;

[0010] Step 4: Based on the obtained drainage system topology model, use two types of geometric forms, points and lines, to schematically and physically express the pipe network relationship in the drainage system topology model, so as to achieve a visual display of the urban underground drainage system.

[0011] Improved, in the urban drainage system visualization processing method based on the pipe network generalization model, in step 2, the process of obtaining the transportation route of the sewage in the entire urban underground drainage system includes steps a1 to a4:

[0012] Step a1: Acquire underground drainage system points and their ancillary facilities data obtained during a city underground pipeline survey; wherein the underground drainage system points data in the underground drainage system points and their ancillary facilities data includes attribute information indicating that the points are pipeline start points or pipeline end points;

[0013] Step a2, obtaining the road centerline in the city electronic map basic database;

[0014] Step a3: Optimally matching the acquired data of urban underground drainage system pipe points and their ancillary facilities with the acquired road centerlines to simulate primary and secondary trunk pipes and trunk pipe routes representing the urban underground drainage system;

[0015] Step a4, retrieve the starting point information and end point information of each pipe point in the underground drainage system, and mark the flow direction of sewage in each pipe of the underground drainage system, forming a transportation route for the sewage trunk pipe to transport sewage through the pump station to the sewage main pipe and finally transport the sewage to the sewage treatment plant.

[0016] Further improved, in the urban drainage system visualization processing method based on the pipe network generalization model, in step a3, the process of performing optimal matching processing on the acquired urban underground drainage system pipe points and their ancillary facilities data with the acquired road center lines to simulate the primary and secondary trunk pipes and trunk pipe routes representing the urban underground drainage system includes the following steps:

[0017] Step b1: Searching for all road centerlines in the neighborhood of the set of pipe points to be matched; wherein the set of pipe points to be matched is formed by all pipe points of the acquired urban underground drainage system;

[0018] Step b2: measure the similarity between the pipe point connecting line as the pipe segment and each candidate road;

[0019] In step b3, the candidate road with the greatest similarity is used as the matching road, and the centerline of the matching road is used as the generalized linear expression of the pipe segment.

[0020] Furthermore, in the urban drainage system visualization processing method based on the pipe network generalization model, the candidate road selection process includes the following steps:

[0021] Step c1, selecting the maximum horizontal coordinate and the minimum vertical coordinate of all the pipe point coordinates in the pipe point set, and establishing an outer rectangle with the selected maximum horizontal coordinate and minimum vertical coordinate as the boundary;

[0022] Step c2, determining the error area: the roads surrounding the set of control points are included in the area where the current position error may exist; wherein the area radius of the area is the maximum distance between the center point of the outer rectangle and each control point in the set of control points;

[0023] Step c3: taking the road segment set within the error area as the candidate roads in the management point set.

[0024] Furthermore, in the urban drainage system visualization processing method based on the pipe network generalization model, the matching road determination process is as follows:

[0025] Step d1, calculating the first node distance, second node distance, and vertical distance from the center point of the outer rectangle to each candidate road in the set of control points; wherein the first node distance of a candidate road is the distance from the center point of the outer rectangle to the starting point of the corresponding candidate road, the second node distance of a candidate road is the distance from the center point of the outer rectangle to the corresponding candidate road point, and the vertical distance of a candidate road is the distance from the center point of the outer rectangle to the foot of the perpendicular to the center point of the outer rectangle on the corresponding candidate road;

[0026] Step d2, calculating the angle between the center line of the outer rectangle and each candidate road;

[0027] Step d3, obtaining the foot of the perpendicular from the center point of the outer rectangle to each candidate road in the set of control points;

[0028] Step d4: determine whether the vertical foot is on the candidate road.

[0029] If the foot of the perpendicular is located on the candidate road, the vertical distance corresponding to the foot of the perpendicular is used as the distance from the center point of the outer rectangle to the corresponding candidate road, and the process proceeds to step d5. Otherwise, the minimum distance value is selected between the first node distance and the second node distance, and this minimum distance value is used as the distance from the center point of the outer rectangle to the corresponding candidate road, and the process proceeds to step d5.

[0030] In step d5, the matching similarity between the control point set and the candidate roads is calculated. The matching similarity is calculated as follows:

[0031] s di =U d -λ d ·d i ;

[0032] s ai =U a -λ a ·d i ;

[0033] s i = s ai +s di ;

[0034] λ a +λ d =1;

[0035] Among them, s i represents the matching similarity between the set of control points and the candidate road i, s ai represents the angle matching similarity between the set of pipe points and the candidate road i, s di represents the distance matching similarity between the control point set and the candidate road i, U a Indicates the maximum angle between the center line of the outer rectangle and all candidate roads, U d represents the maximum distance from the center point of the outer rectangle to all candidate roads, λ a represents the weight of the distance, λ d represents the weight of the angle;

[0036] Among them, the angle between any road section and the center line of the outer rectangle exceeds U a Or the distance between any road segment and the center point of the outer rectangle exceeds U d , then it is determined that any road segment has no similarity with the control point set, and any road segment is deleted from the candidate roads;

[0037] In step d6, the candidate road corresponding to the matching similarity with the maximum matching similarity value is used as the matching road section.

[0038] Further improved, in this invention, the urban drainage system visualization processing method based on the pipe network generalization model also includes: based on the city's underground drainage pipe network census database, performing drainage facility data collection and classification and reorganization; and, according to the entire process of sewage from generation, collection, transportation, treatment to discharge, spatial positioning encoding of the drainage pipe network topology model.

[0039] Furthermore, in the urban drainage system visualization processing method based on the pipe network generalization model, the spatial positioning encoding process is as follows:

[0040] Drainage facilities are divided into five basic categories: drainage households, pipe networks, pumping stations, sewage treatment plants and drainage outlets;

[0041] A unique code is assigned to each drainage facility based on preset coding rules; wherein, the unique code is encoded using 18 characters, and is composed of an 8-bit spatial positioning code, a 6-bit facility classification code and a 4-bit sequence code from left to right.

[0042] Compared with the existing technology, the advantages of the present invention are: the urban drainage system visualization processing method based on the pipe network generalization model of the invention constructs a drainage system framework model that expresses the overall spatial distribution form of the entire urban drainage system, a drainage system generalization model that reflects the upstream and downstream topological relationship of sewage treatment plants and drainage pumping stations and the relationship between the connecting trunk pipelines and main pipes, and a drainage system topology model that can reflect the layout of the underground sewage system and the flow direction of sewage in the city. Then, based on the obtained drainage system topology model, the pipe network relationship in the drainage system topology model is schematically physically expressed using two types of geometric forms, points and lines, to achieve a visual display of the urban underground drainage system, thereby effectively solving the problem of "invisible" and "unusable" urban underground pipe networks, truly and comprehensively reflecting the overall topological relationship and global operation status of the urban underground drainage system, and meeting the spatial display and analysis application needs of various industries and departments in the construction of new smart cities for underground pipeline data. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the flow of a method for visualizing an urban drainage system based on a pipe network generalization model in an embodiment of the present invention;

[0044] Figure 2 Schematic diagram of the error region determined in an embodiment of the present invention;

[0045] Figure 3 Schematic diagram of the angles between the center line of the outer rectangle and each candidate road in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0047] This embodiment provides a method for visualizing an urban drainage system based on a pipe network generalization model. Figure 1 As shown, the urban drainage system visualization processing method based on the pipe network generalization model of this embodiment includes the following steps 1 to 4:

[0048] Step 1: Construct a drainage system framework model that expresses the overall spatial distribution of the entire urban drainage system. This drainage system framework model uses the sewage treatment plant as the main node and the pumping station that delivers sewage to the sewage treatment plant as the skeleton node. The lines between the sewage treatment plant and each pumping station, and between pumping stations, are used to schematically outline the drainage system line framework, thereby characterizing the sewage flow relationship characteristics within the entire system.

[0049] Step 2: Based on the constructed drainage system framework model, a drainage system generalization model is constructed to reflect the upstream and downstream topological relationships between sewage treatment plants and drainage pumping stations, as well as the interconnected trunk pipelines and main pipes. This drainage system generalization model represents the sewage transportation route within the entire urban underground drainage system.

[0050] Step 3: Simplify the constructed drainage system generalization model and retain all major pipelines that can reflect the layout of the city's underground sewage system and the direction of sewage flow. The topological relationship formed by all the retained major pipelines is used as the drainage system topology model;

[0051] Step 4: Based on the resulting drainage system topology model, use point and line geometric forms to schematically represent the pipe network relationships within the model, achieving a visual representation of the urban underground drainage system. For example, using point and line geometric forms to schematically represent the actual pipe network, different model display levels can be set based on different display scales. The display scales, resolutions, and model levels for each level are shown in Table 1 below.

[0052] Table 1

[0053] Display Level Display Aspect Ratio Show Model Level Data source scale Ground resolution (meters / pixel) 11 1:288,895.85 DL1 1:250,000 76.437028 12 1:144,447.93 DL1 1:250,000 38.218514 13 1:72,223.96 DL1 1:50,000 19.109257 14 1:36,111.98 DL1 1:50,000 9.554629 15 1:18,055.99 DL1 1:10,000 4.777314 16 1:9,028.00 DL2 1:10,000 2.388657 17 1:4,514.00 DL2 1:10,000 1.194329 18 1:2,257.00 DL2 1:2000 or 1:1000 0.597164 19 1:1,128.50 DL2 1:2000 or 1:1000 0.298582 20 1:564.25 DL3 1:1000 or 1:500 0.149291

[0054] Specifically in this embodiment, in the above step 2, the process of obtaining the sewage transportation route in the entire urban underground drainage system includes steps a1 to a4:

[0055] Step a1: Acquire underground drainage system points and their ancillary facilities data obtained during a city underground pipeline survey; wherein the underground drainage system points data in the underground drainage system points and their ancillary facilities data includes attribute information indicating that the points are pipeline start points or pipeline end points;

[0056] Step a2, obtaining the road centerline in the city electronic map basic database;

[0057] Step a3: Optimally matching the acquired data of urban underground drainage system pipe points and their ancillary facilities with the acquired road centerlines to simulate primary and secondary trunk pipes and trunk pipe routes representing the urban underground drainage system;

[0058] Step a4, retrieve the starting point information and end point information of each pipe point in the underground drainage system, and mark the flow direction of sewage in each pipe of the underground drainage system, forming a transportation route for the sewage trunk pipe to transport sewage through the pump station to the sewage main pipe and finally transport the sewage to the sewage treatment plant.

[0059] Specifically, in step a3 above, the process of optimally matching the acquired data of urban underground drainage system pipe points and their ancillary facilities with the acquired road centerlines to simulate the primary and secondary trunk pipes and trunk pipe routes representing the urban underground drainage system includes the following steps b1 to b3:

[0060] Step b1: Searching for all road centerlines in the neighborhood of the set of pipe points to be matched; wherein the set of pipe points to be matched is formed by all pipe points of the acquired urban underground drainage system;

[0061] Step b2: measure the similarity between the pipe point connecting line as the pipe segment and each candidate road;

[0062] In step b3, the candidate road with the greatest similarity is used as the matching road, and the centerline of the matching road is used as the generalized linear expression of the pipe segment.

[0063] It should be noted that, in this embodiment, the candidate road selection process includes the following steps c1 to c3:

[0064] Step c1, selecting the maximum horizontal coordinate and the minimum vertical coordinate of all the pipe point coordinates in the pipe point set, and establishing an outer rectangle with the selected maximum horizontal coordinate and minimum vertical coordinate as the boundary;

[0065] Step c2, determining the error area: the roads surrounding the set of control points are included in the area where the current position error may exist; wherein the area radius of the area is the maximum distance between the center point of the outer rectangle and each control point in the set of control points;

[0066] For details on the error range, see Figure 2 As shown in the figure: the radius r of the error area is the maximum distance between the center point O of the outer rectangle R and each point in the control point set P, that is, r=Max(d1, d2, ..., dn). The set of road sections within the error area formed by the radius r is the candidate road section.

[0067] Step c3: taking the road segment set within the error area as the candidate roads in the management point set.

[0068] To further illustrate, in the urban drainage system visualization processing method based on the pipe network generalization model of this embodiment, the above-mentioned matching road determination process includes the following steps d1 to d6:

[0069] Step d1, calculating the first node distance, second node distance, and vertical distance from the center point of the enclosing rectangle to each candidate road in the set of control points; wherein the first node distance of a candidate road is the distance from the center point of the enclosing rectangle to the starting point of the corresponding candidate road, the second node distance of a candidate road is the distance from the center point of the enclosing rectangle to the corresponding candidate road point, and the vertical distance of a candidate road is the distance from the center point of the enclosing rectangle to the foot of the perpendicular to the center point of the enclosing rectangle on the corresponding candidate road;

[0070] For example, the distance from the center point O of the outer rectangle to the first node of any candidate road in the pipe point set is marked as d m The distance from the center point O of the outer rectangle to the second node of any candidate road in the pipe point set is marked as d n The vertical distance from the center point O of the outer rectangle to any candidate road in the pipe point set is marked as d mn ;

[0071] Step d2, calculating the angle between the center line of the outer rectangle and each candidate road;

[0072] In this embodiment, see Figure 3 As shown, assuming that AC and CD are candidate roads, the distance from the center point O of the outer rectangle to the two candidate roads AC and CD is marked as d AC and d CD , the angle between the center line l of the outer rectangle and the candidate road AC is θ AC , the angle between the center line l of the outer rectangle and the candidate road CB is θ CD ;

[0073] The distance from the center of the outer rectangle O to the first node of the candidate road AC is marked as d A The distance from the center of the outer rectangle O to the second node of the candidate road AC is marked as d c ;

[0074] The distance from the center of the outer rectangle O to the first node of the candidate road CD is marked as d D The distance from the center of the outer rectangle O to the second node of the candidate road CD is marked as d c ;

[0075] Step d3, obtaining the foot of the perpendicular from the center point of the outer rectangle to each candidate road in the set of control points;

[0076] Step d4: determine whether the vertical foot is on the candidate road.

[0077] If the foot of the perpendicular is located on the candidate road, the vertical distance corresponding to the foot of the perpendicular is used as the distance from the center point of the outer rectangle to the corresponding candidate road, and the process proceeds to step d5. Otherwise, the minimum distance value is selected between the first node distance and the second node distance, and this minimum distance value is used as the distance from the center point of the outer rectangle to the corresponding candidate road, and the process proceeds to step d5.

[0078] For example, when the foot of the perpendicular is located on the candidate road, the vertical distance d corresponding to the foot of the perpendicular is mn As the distance from the center point of the outer rectangle to the corresponding candidate road; otherwise, the first node distance d m Distance d from the second node n The minimum distance value in is taken as the distance from the center point of the outer rectangle to the corresponding candidate road;

[0079] In step d5, the matching similarity between the control point set and the candidate roads is calculated. The matching similarity is calculated as follows:

[0080] s di =U d -λ d ·d i ;

[0081] s ai =U a -λ a ·d i ;

[0082] s i = s ai +s di ;

[0083] λ a +λ d =1;

[0084] Among them, s i represents the matching similarity between the set of control points and the candidate road i, s ai represents the angle matching similarity between the set of pipe points and the candidate road i, s di represents the distance matching similarity between the control point set and the candidate road i, U a Indicates the maximum angle between the center line of the outer rectangle and all candidate roads, U d represents the maximum distance from the center point of the outer rectangle to all candidate roads, λ a represents the weight of the distance, λ d represents the weight of the angle;

[0085] Among them, the angle between any road section and the center line of the outer rectangle exceeds U a Or the distance between any road segment and the center point of the outer rectangle exceeds U d, then it is determined that any road segment has no similarity with the control point set, and any road segment is deleted from the candidate roads;

[0086] In step d6, the candidate road corresponding to the matching similarity with the maximum matching similarity value is used as the matching road section.

[0087] In addition, according to actual needs, in this embodiment, the urban drainage system visualization processing method based on the pipe network generalization model can also be used to perform drainage facility data collection and classification and reorganization based on the city's underground drainage pipe network census database; and the drainage pipe network topology model can be spatially positioned and encoded according to the entire process of sewage from generation, collection, transportation, treatment to discharge.

[0088] Specifically, the spatial positioning encoding process here is as follows:

[0089] Drainage facilities are divided into five basic categories: drainage households, pipe networks (sewage pipe networks, rainwater pipe networks, combined pipe networks), pumping stations (sewage pumping stations, rainwater pumping stations), sewage treatment plants, and drainage outlets (sewage outlets into rivers (seas), drainage outlets into rivers (seas)).

[0090] A unique code is assigned to each drainage facility based on a preset coding rule; wherein the unique code is encoded using 18 characters, and is composed of an 8-bit spatial positioning code, a 6-bit facility classification code, and a 4-bit sequence code from left to right. For example, in this embodiment, the spatial positioning code is as follows:

[0091] (1) The spatial positioning code is the 8-digit 1:500 map sheet number of the survey unit where the pipeline is located;

[0092] (2) The 6-digit facility classification code is divided into a 2-digit category code, a 2-digit "source-network-factory-outlet" major category code, and a 2-digit minor category code; for example, WS is the "sewage" category code, 02 is the "sewage network" major category code, and 03 is the "sewage pipeline" minor category code;

[0093] (3) The 4-digit pipe section sequence code is used to number the pipe sections and their associated drainage facilities in sequence according to their orientation. The east-west direction is numbered from west to east, and the north-south direction is numbered from north to south. The value range is 0001-9999.

[0094] Although the preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A visualization processing method for urban drainage system based on a pipe network generalization model, characterized in that: The steps include: Step 1: Construct a drainage system framework model that represents the overall spatial distribution of the entire urban drainage system. This model uses the sewage treatment plant as the primary node and the pumping stations that deliver sewage to the sewage treatment plant as the skeleton nodes. The lines between the sewage treatment plant and each pumping station, and between pumping stations, are used to schematically outline the drainage system's line framework, thereby characterizing the sewage flow relationship characteristics within the entire system. Step 2: Based on the constructed drainage system framework model, a generalized drainage system model is constructed to reflect the upstream and downstream topological relationships of sewage treatment plants and drainage pumping stations, as well as the interconnected trunk pipelines and main pipe relationships. This generalized drainage system model represents the sewage transportation route within the entire urban underground drainage system. Step 3: Simplify the constructed drainage system generalization model and retain all major pipelines that can reflect the layout of the city's underground sewage system and the direction of sewage flow. The topological relationship formed by all the retained major pipelines is used as the drainage system topology model; Step 4: Based on the obtained drainage system topology model, use two types of geometric forms, points and lines, to schematically and physically express the pipe network relationship in the drainage system topology model, thereby realizing a visual display of the urban underground drainage system; wherein: In step 2, the process of obtaining the sewage transportation route in the entire urban underground drainage system includes steps a1 to a4: Step a1: Acquire underground drainage system points and their ancillary facilities data obtained during a city underground pipeline survey; wherein the underground drainage system points data in the underground drainage system points and their ancillary facilities data includes attribute information indicating that the points are pipeline start points or pipeline end points; Step a2, obtaining the road centerline in the city electronic map basic database; Step a3: Optimally matching the acquired data of urban underground drainage system pipe points and their ancillary facilities with the acquired road centerlines to simulate primary and secondary trunk pipes and trunk pipe routes representing the urban underground drainage system; Step a4: Retrieve the acquired starting and ending point information of each pipe point in the underground drainage system, and mark the flow direction of the sewage in each pipe of the underground drainage system, forming a transportation route for the sewage trunk pipe to transport the sewage through the pumping station to the sewage main pipe and finally to the sewage treatment plant; In step a3, the process of optimally matching the acquired data of urban underground drainage system pipe points and their ancillary facilities with the acquired road centerlines to simulate the primary and secondary trunk pipes and trunk pipe routes representing the urban underground drainage system includes the following steps b1 to b3: Step b1: Searching for all road centerlines in the neighborhood of the set of pipe points to be matched; wherein the set of pipe points to be matched is formed by all pipe points of the acquired urban underground drainage system; Step b2: measure the similarity between the pipe point connecting line as the pipe segment and each candidate road; Step b3: The candidate road with the greatest similarity is used as the matching road, and the centerline of the matching road is used as the generalized linear expression of the pipe segment; wherein: The candidate road selection process includes the following steps c1 to c3: Step c1, selecting the maximum horizontal coordinate and the minimum vertical coordinate of all the pipe point coordinates in the pipe point set, and establishing an outer rectangle with the selected maximum horizontal coordinate and minimum vertical coordinate as the boundary; Step c2, determining the error area: the roads surrounding the set of control points are included in the area where the current position error may exist; wherein the area radius of the area is the maximum distance between the center point of the outer rectangle and each control point in the set of control points; Step c3, taking the road segment set within the error area as the candidate road in the management point set; The matching road determination process is as follows: Step d1, calculating the first node distance, second node distance, and vertical distance from the center point of the outer rectangle to each candidate road in the set of control points; wherein the first node distance of a candidate road is the distance from the center point of the outer rectangle to the starting point of the corresponding candidate road, the second node distance of a candidate road is the distance from the center point of the outer rectangle to the corresponding candidate road point, and the vertical distance of a candidate road is the distance from the center point of the outer rectangle to the foot of the perpendicular to the center point of the outer rectangle on the corresponding candidate road; Step d2, calculating the angle between the center line of the outer rectangle and each candidate road; Step d3, obtaining the foot of the perpendicular from the center point of the outer rectangle to each candidate road in the set of control points; Step d4: determine whether the vertical foot is on the candidate road. If the foot of the perpendicular is located on the candidate road, the vertical distance corresponding to the foot of the perpendicular is used as the distance from the center point of the outer rectangle to the corresponding candidate road, and the process proceeds to step d5. Otherwise, the minimum distance value is selected between the first node distance and the second node distance, and this minimum distance value is used as the distance from the center point of the outer rectangle to the corresponding candidate road, and the process proceeds to step d5. In step d5, the matching similarity between the control point set and the candidate roads is calculated. The matching similarity is calculated as follows: s di =U d -λ d ·d i ; s ai =U a -λ a ·d i ; s i = s ai +s di ; l a +l d =1; Among them, s i represents the matching similarity between the set of control points and the candidate road i, s ai represents the angle matching similarity between the set of pipe points and the candidate road i, s di represents the distance matching similarity between the control point set and the candidate road i, U a Indicates the maximum angle between the center line of the outer rectangle and all candidate roads, U d represents the maximum distance from the center point of the outer rectangle to all candidate roads, λ a represents the weight of the distance, λ d represents the weight of the angle; Among them, the angle between any road section and the center line of the outer rectangle exceeds U a Or the distance between any road segment and the center point of the outer rectangle exceeds U d , then it is determined that any road segment has no similarity with the control point set, and any road segment is deleted from the candidate roads; In step d6, the candidate road corresponding to the matching similarity with the maximum matching similarity value is used as the matching road section.

2. The urban drainage system visualization processing method based on the pipe network generalization model according to claim 1 is characterized in that: Also includes: Based on the city's underground drainage network census database, collect and classify drainage facility data; In addition, the drainage network topology model is spatially positioned and coded based on the entire process of sewage generation, collection, transportation, treatment and discharge.

3. The urban drainage system visualization processing method based on the pipe network generalization model according to claim 2 is characterized in that: The spatial positioning encoding process is as follows: Drainage facilities are divided into five basic categories: drainage households, pipe networks, pumping stations, sewage treatment plants and drainage outlets; A unique code is assigned to each drainage facility based on preset coding rules; wherein, the unique code is encoded using 18 characters, and is composed of an 8-bit spatial positioning code, a 6-bit facility classification code and a 4-bit sequence code from left to right.

Images