A method and system for reconstructing topological relations of a sewer network based on geometric constraints

Abstract

Specifically, this invention is a method and system for reconstructing the topology of drainage pipe networks based on geometric constraints. The method includes: constructing a manhole attribute table; establishing a coordinate system based on the positional relationship between the current manhole and potential connecting manholes; calculating the distance between the current manhole and potential connecting manholes using a simplified plane approximation method; excluding potential connecting manholes whose pipe opening direction angle θ deviates beyond the error range; excluding pipe openings of potential connecting manholes where the sum of two direction angles cannot be complementary within the error range; checking for consistent pipe diameters; selecting the closest pipe opening as the connected matching pipe opening; determining upstream and downstream relationships; outputting a connection relationship table; and storing the reconstructed pipe network topology. The advantages of this invention are: automatically reconstructing the drainage pipe network topology through geometric constraints, solving the problems of difficulty in manually discovering hidden connections in drainage pipe networks, high costs, and unreliability; and achieving low-cost, high-precision pipe network digitization with a full-process IoT system.

Description

Technical Field

[0001] This invention relates to the field of drainage pipe network technology in water conservancy and water affairs, specifically to a method and system for reconstructing the topology of drainage pipe networks based on geometric constraints. Background Technology

[0002] With the acceleration of urbanization, the digital and intelligent management of municipal drainage pipe networks, as core infrastructure of underground concealed engineering, has become a critical requirement for urban safety operation and maintenance. However, due to the complex structure, concealed spatial distribution, and lack of historical data of the pipe network system, its management still faces many challenges. Due to poor management of historical data, drainage pipe network data in many cities is scattered across different departments or storage media, and some data has even been lost or damaged, resulting in a lack of complete and accurate reference data when reconstructing the pipe network topology. Dynamically changing pipe network environments, such as pipe renovations, the addition of branch pipes, or emergency repairs, often fail to update data in a timely manner, causing a disconnect between the management system and the actual pipe network status. These problems not only reduce operation and maintenance efficiency but may also lead to safety hazards such as poor drainage, flooding, and even pipe collapses, threatening urban public safety.

[0003] Currently, most cities still rely on traditional manual surveying methods for data collection, such as on-site geophysical exploration. This involves measuring information such as the diameter, depth, latitude and longitude coordinates, and elevation coordinates of manholes, and manually recording this information in paper forms or simple electronic documents. Subsequently, this data needs to be manually compiled and organized, and manually drawn into a pipeline network topology diagram for use in planning, maintenance, and emergency management.

[0004] This traditional manual approach has significant limitations. First, it is extremely inefficient; manual measurement and recording are time-consuming and labor-intensive, especially in large-scale pipeline systems where data collection cycles are long, making it difficult to meet the rapid updating needs of modern urban pipeline data. Second, it is costly, relying heavily on manpower for field surveys and data processing, and is easily affected by external factors such as weather and traffic, leading to project delays and budget overruns. Furthermore, another major flaw of the traditional method is its insufficient depth in exploring the correlations between pipeline network data. Manually drawn topologies often only reflect surface connections, neglecting the intrinsic relationships between multi-dimensional pipeline data. This simplistic approach to topology processing results in a lack of sufficient scientific rigor and systematicity in the pipeline topology, failing to accurately reflect the actual operating status of the pipeline network. This can lead to biases in the final generated pipeline topology, affecting subsequent analysis and decision-making.

[0005] Therefore, there is an urgent need to introduce more efficient digital technologies, such as pipe caliper gauges, IoT sensors, and AI-assisted analysis, to improve the automation of pipeline network data collection, reduce manual intervention, and enhance data accuracy and real-time performance. Simultaneously, a unified pipeline network data analysis and management platform needs to be established to integrate multi-source heterogeneous data, enabling dynamic updates and intelligent analysis of pipeline network information, and providing more reliable technical support for the planning, operation, maintenance, and emergency response of urban drainage systems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and system for reconstructing the topology of drainage pipe networks based on geometric constraints. By automatically reconstructing the topology of drainage pipe networks through geometric constraints, this invention solves the problems of difficulty in manually discovering hidden connections in drainage pipe networks, high costs, and unreliability. It is also equipped with a full-process Internet of Things system to achieve low-cost and high-precision digitization of pipe networks.

[0007] To achieve the above objectives, a drainage network topology reconstruction method based on geometric constraints is designed, comprising the following steps: Step 1: Construct a manhole attribute table, obtain the attribute data of manholes and their pipe openings, and load them into the manhole attribute table. The attribute data includes at least spatial coordinates, pipe diameter, orientation angle, and pipe bottom elevation; Step 2: Using the current manhole opening as the center, search for potential target manholes within a preset distance threshold range. Establish a coordinate system based on the positional relationship between the current manhole and potential connecting manholes, and divide the current manhole's Cartesian coordinate system into four quadrants; Step 3: Calculate the distance between the current manhole and potential connecting manholes using a simplified plane approximation method; Step 4: Calculate the theoretical pipe opening orientation angle θ of each potential connecting manhole in the four quadrants relative to the current manhole, and determine whether there is a potential connecting manhole whose measured orientation angle deviates from the theoretical pipe opening orientation angle θ within the allowable error range, excluding potential connecting manholes exceeding the error range; Step 5: For the potential connecting manholes screened in Step 4, check... Step 6: Check the offset relationship between the direction angle of the current manhole opening and the direction angle of the potential connecting manhole opening. Determine if the sum of the two direction angles is complementary within the error range. If the offset relationship cannot be satisfied, exclude the potential connecting manhole opening. Step 7: For the potential connecting manholes filtered in Step 5, determine if the pipe diameters of the current manhole and the potential connecting manholes are the same or within the allowable error range. If they are inconsistent, exclude the potential connecting manhole. Step 8: If a certain opening of the current manhole corresponds to multiple potential connecting manhole openings filtered in Step 6, select the closest opening as the connected matching opening. Step 9: Determine the upstream and downstream relationship based on the bottom elevation and upper elevation of the connected matching opening. Step 10: Traverse all manhole openings and output the connection relationship table. Unconnected openings that do not meet the above geometric constraints need to be manually confirmed and corrected. Step 11: Store the reconstructed pipeline topology relationship as a data file and a graphic file. The data file can be directly imported into the GIS platform, and the graphic file can be directly visualized and previewed.

[0008] Preferably, the present invention further includes: the directional angle is defined as follows: with the geomagnetic direction as a reference, due north is defined as 0 degrees, and the angle increases sequentially in a clockwise direction, with due east being 90 degrees, due south being 180 degrees, and due west being 270 degrees.

[0009] Preferably, the present invention further includes: step 1 includes: defining a manhole attribute table, wherein the manhole attribute table includes manhole number, pipe opening number, longitude coordinates, latitude coordinates, high-level coordinates, measured pipe diameter, designed pipe diameter, direction angle, pipe bottom elevation, upstream manhole number, downstream manhole number, manhole material, manhole cover shape, manhole cover size, manhole cover material, and pipe material.

[0010] Preferably, the present invention further includes: Step 2 includes: The division of the four quadrants is defined as follows: A plane rectangular coordinate system is established with the current inspection well as the origin, and two mutually perpendicular coordinate axes, the X-axis and the Y-axis, are set, with the positive direction of the X-axis pointing due east and the positive direction of the Y-axis pointing due north; the coordinates of the origin of the coordinate axes are set as (X1, Y1), and the coordinates of the potential connecting inspection wells are set as (X2, Y2). When the coordinates of the potential connecting inspection wells satisfy X2 > X1 and Y2 > Y1, the potential connecting inspection wells are located in the first quadrant; when X2 < X1 and Y2 > Y1, the potential connecting inspection wells are located in the second quadrant; when X2 > X1 and Y2 < Y1, the potential connecting inspection wells are located in the third quadrant; when X2 < X1 and Y2 < Y1, the potential connecting inspection wells are located in the fourth quadrant; X1 and Y1 are the horizontal and vertical coordinates of the current inspection well in the directional angular coordinate system, respectively, and X2 and Y2 are the horizontal and vertical coordinates of the potential connecting inspection wells in the directional angular coordinate system, respectively.

[0011] Preferably, the present invention further includes: step 3 includes: calculating the distance between the current inspection well and the potential connecting inspection well using a simplified plane approximation method, the calculation formula being: R²=(X2-X1)²+(Y2-Y1)²; where X1 and Y1 are the horizontal and vertical coordinates of the current inspection well in the azimuth coordinate system, respectively, X2 and Y2 are the horizontal and vertical coordinates of the potential connecting inspection well in the azimuth coordinate system, and R is the distance between the two wells.

[0012] Preferably, the present invention further includes: Step 4 includes: calculating the theoretical nozzle orientation angle θli of the potential connection inspection well relative to the current inspection well, the calculation method being: when the potential connection inspection well is in the first quadrant, θli = arctan[(X1-X2) / (Y1-Y2)]; when the potential connection inspection well is in the second quadrant, θli = 270° + arctan[(Y1-Y2) / (X1-X2)]; when the potential connection inspection well is in the third quadrant, θli = 90° + arctan[(Y1-Y2) / (X1-X2)]; when the potential connection inspection well is in the fourth ... Theoretical = 180° + arctan[(X1-X2) / (Y1-Y2)]; where X1 and Y1 are the horizontal and vertical coordinates of the current inspection well in the azimuth coordinate system, respectively, and X2 and Y2 are the horizontal and vertical coordinates of the potential connecting inspection well in the azimuth coordinate system, respectively; determine whether there exists an actual pipe opening direction angle in the current inspection well that satisfies |θX-θtheoretical|≤Δθ. If so, proceed to step 5; otherwise, exclude the potential connecting inspection well, where θX is the actual pipe opening direction angle in any current inspection well, and Δθ is a preset azimuth error threshold.

[0013] Preferably, the present invention further includes: Step 5 includes: for each pipe opening of the current inspection well, recording its theoretical direction angle relative to the geomagnetic north as θ1; for each pipe opening of each potential connected inspection well, recording its theoretical direction angle relative to the geomagnetic north as θ2; setting Δθ as a preset direction angle error threshold; if |θ1 - θ2| is within the interval [180° - Δθ, 180° + Δθ], it is determined that the pipe opening of the potential connected inspection well and the pipe opening of the current inspection well satisfy the direction angle reverse constraint, and enter Step 6, otherwise exclude the potential connected inspection well.

[0014] Preferably, the present invention further includes: Step 8 includes: judging the upstream and downstream relationship based on the pipe bottom elevation and the top elevation of the connected matching pipe openings. If H1 - h1 > H2 - h2, the pipe opening of the current inspection well is the upstream node. If H1 - h2 < H2 - h2, the pipe opening of the current inspection well is the downstream node, where H1 and h1 are respectively the top elevation and the pipe bottom elevation of the current inspection well, and H2 and h2 are respectively the top elevation and the pipe bottom elevation of the potential connected inspection well.

[0015] Preferably, the present invention further includes: in Step 7, selecting the pipe opening with the closest distance as the connected matching pipe opening, specifically including selecting the pipe opening with the closest distance to the current pipe opening as the connected matching pipe opening among multiple potential connected pipe openings.

[0016] The present invention also provides a drainage pipe network topology relationship reconstruction system based on geometric constraints, including a front-end data acquisition layer, a cloud data management and analysis platform layer, and a Web application layer; the front-end data acquisition layer includes an APP, and the APP communicates with a pipe diameter gauge, RTK, a sonar scanner, and a pipe robot to obtain pipe data information, and also supports manual input of data information, and transmits the data to the cloud data management and analysis platform layer through a 4G network; the cloud data management and analysis platform layer includes a cloud server and a cloud database, which are used to store and manage pipe network data; the Web application layer communicates with the cloud data management and analysis platform layer to implement account management, data management, pipe network topology analysis, data download, and GIS interaction; the pipe network topology analysis adopts the method described above.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] 1. Automation and high efficiency. Automatically reconstruct the pipe network topology through geometric constraint relationships, significantly reducing manual intervention and improving analysis efficiency. Automatically identify hidden connection relationships, solving the problems of time-consuming, laborious, and easy to miss in traditional manual inspections.

[0019] 2. Multi-dimensional and Precise Analysis. This paper proposes for the first time to incorporate pipeline direction angle as an attribute into pipeline network data. Combined with the analysis of other data, and through geometric constraints, it automatically analyzes the topological connections and upstream / downstream relationships of the pipeline network, enabling precise reasoning of topological relationships and improving the accuracy of judgments. It also deeply mines the geometric correlation characteristics of manhole data, systematically constructs analytical models, and enhances the scientific rigor and reliability of the results.

[0020] 3. End-to-End Digital Management. Covering the entire chain from data acquisition (front-end APP + measurement equipment), cloud storage management to web interactive applications, enabling real-time transmission, analysis, and visualization of pipeline network data. Supports direct import and export to GIS platforms and preview of graphic files. Integrating IoT (front-end device communication), cloud computing (cloud platform), and spatial analysis technologies, it constructs an intelligent management system, providing key technical support for smart water management and driving the industry's digital transformation.

[0021] 4. Significant cost-effectiveness. It reduces the cost of digital pipeline network construction and minimizes the need for manual surveying and subsequent adjustments. Through standardized data collection and cloud sharing, it optimizes resource utilization. Attached Figure Description

[0022] Figure 1 A schematic diagram defining the direction angle;

[0023] Figure 2 This is a plan view of WS002 in Embodiment 1;

[0024] Figure 3 This is a schematic diagram showing the current manhole planarization divided into four quadrants in Example 1;

[0025] Figure 4 In Example 1, when WS002 is in the first quadrant, the theoretically existing nozzle orientation angle θ is...

[0026] Figure 5 In Example 1, when WS002 is in the second quadrant, the theoretically existing nozzle orientation angle θ exists.

[0027] Figure 6 This refers to the theoretically existing nozzle orientation angle θ when WS002 is in the third quadrant in Example 1.

[0028] Figure 7 This refers to the theoretically existing nozzle orientation angle θ when WS002 is in the fourth quadrant in Example 1.

[0029] Figure 8 This is a schematic diagram illustrating the principle of opposite connecting direction angles in Example 1;

[0030] Figure 9 This is a schematic diagram of the output connection relationship in Example 1;

[0031] Figure 10 This is a schematic diagram of the overall system framework in Example 2. Detailed Implementation

[0032] To make the purpose, principle and structure of the present invention clearer, the following description is provided in conjunction with the accompanying drawings and specific embodiments.

[0033] This invention provides a method and system for reconstructing the topology of drainage pipe networks based on geometric constraints.

[0034] During implementation, the process begins with a front-end data acquisition layer APP communicating with pipeline calipers, RTK, sonar scanners, and pipeline inspection robots, either on the ground or underground. Alternatively, manual data entry by operators collects multidimensional data for each manhole and its pipe opening. After collection, the data is uploaded in real-time to a cloud-based data management and analysis platform via a 4G network. Data collection uses manholes as primary measurement points and each pipe opening within a manhole as secondary measurement points. Primary measurement points record manhole number, latitude and longitude coordinates, elevation coordinates, upstream and downstream manhole numbers, manhole material, manhole cover shape, manhole cover size, and manhole cover material. Secondary measurement points record pipe diameter, pipe direction angle, pipe bottom elevation, flow direction, and pipe material. All data is written into the cloud database of the cloud-based data management and analysis platform, forming a manhole attribute table containing fields such as manhole number, pipe opening number, longitude coordinates, latitude coordinates, elevation coordinates, measured pipe diameter, designed pipe diameter, direction angle, pipe bottom elevation, upstream manhole number, downstream manhole number, manhole material, manhole cover shape, manhole cover size, manhole cover material, and pipe material. The azimuth angle is defined with reference to the geomagnetic direction, starting at 0 degrees due north, increasing clockwise to 90 degrees due east, 180 degrees due south, and 270 degrees due west. The pipe openings are numbered sequentially according to the number of pipe openings in the manhole. For example, if manhole WS001 is a two-way manhole, the pipe openings are numbered WS001-1 and WS001-2. If manhole WS002 is a three-way manhole, the pipe openings are numbered WS002-1, WS002-2, and WS002-3.

[0035] After receiving the data, the cloud-based data management and analysis platform allows users to log in via the web application layer, select the pipeline engineering data for the area to be analyzed, and initiate automatic pipeline topology analysis. During analysis, the platform uses the location of any current manhole as the origin and searches for all potential connecting manholes within a default search radius of 200m. The current manhole's Cartesian coordinate system is divided into four quadrants: the X-axis is positive to the right, and the Y-axis is positive upwards. A potential connecting manhole is located in the first quadrant if its coordinates satisfy X2 > X1 and Y2 > Y1; in the second quadrant if X2 < X1 and Y2 > Y1; in the third quadrant if X2 > X1 and Y2 < Y1; and in the fourth quadrant if X2 < X1 and Y2 < Y1. The distance R between the current manhole and potential connecting manholes is calculated using a simplified planar approximation method, with the formula R² = (X2 - X1)² + (Y2 - Y1)². Then, the theoretical nozzle orientation angle θli of the potential connection inspection well relative to the current inspection well is calculated: when the potential connection inspection well is in the first quadrant, θli = arctan[(Y2-Y1) / (X2-X1)], in the second quadrant, θli = 270° + arctan[(Y2-Y1) / (X1-X2)], in the third quadrant, θli = 90° + arctan[(Y1-Y2) / (X2-X1)], and in the fourth quadrant, θli = 180° + arctan[(Y1-Y2) / (X1-X2)]; it is then determined whether there is an actual nozzle orientation angle θX in the current inspection well that satisfies |θX - θli| ≤ Δθ, where Δθ is a preset orientation angle error threshold, with a default value of 20°. If it exists, the process continues; otherwise, the potential connection inspection well is excluded.

[0036] For potential connecting manholes that pass the initial screening based on azimuth angle, the reverse azimuth constraint is further verified: The theoretical azimuth angle of each pipe opening of the current manhole relative to the geomagnetic north is denoted as θ1, and the theoretical azimuth angle of each pipe opening of the potential connecting manholes relative to the geomagnetic north is denoted as θ2. If |θ1-θ2| falls within the interval [180°-Δθ, 180°+Δθ], the reverse azimuth constraint is satisfied, with Δθ also set to 20°; otherwise, it is excluded. After satisfying the reverse constraint, the pipe diameters of the two openings are checked for consistency. If they are consistent, the process continues; otherwise, it is excluded. If a certain opening of the current manhole corresponds to multiple openings of potential connecting manholes, the closest opening is selected as the connecting matching opening based on the principle of proximity. After identifying the connected pipe openings, the upstream and downstream relationships are determined based on the bottom and top elevations of the connected pipe openings: Let H1 and h1 be the top and bottom elevations of the current manhole, respectively, and H2 and h2 be the top and bottom elevations of potential connected manholes, respectively. If H1-h1 > H2-h2, the current manhole opening is an upstream node; if H1-h1 < H2-h2, the current manhole opening is a downstream node. The platform iterates through all manhole openings according to the above steps, automatically generating a connection relationship table. Unconnected pipe openings that do not meet the geometric constraints are manually confirmed and corrected. Finally, the platform stores the reconstructed pipeline topology as data files and graphic files. The data files can be directly imported into the GIS platform, and the graphic files can be directly visualized and previewed for the pipeline topology connections.

[0037] Example 1: (1) The present invention proposes a method for reconstructing the topology of drainage pipe network based on geometric constraints, which is described in detail below.

[0038] First, define the manhole attribute table, collect and check the manhole attribute table, and the attribute data includes: manhole number, pipe opening number, longitude coordinates, latitude coordinates, high-rise coordinates, measured pipe diameter, designed pipe diameter, direction angle, pipe bottom elevation, upstream manhole number, downstream manhole number, manhole material, manhole cover shape, manhole cover size, manhole cover material, pipe material, etc.

[0039] Examples of important inspection well attributes are shown in Table 1.

[0040] Table 1. Examples of important inspection well attributes.

[0041]

[0042] This invention is the first to propose adding azimuth angles and pipe opening numbers to the inspection well attribute table. The azimuth angle is defined as follows: with geomagnetic direction as a reference, true north is defined as 0 degrees, and the angles increase clockwise from true north. East is 90 degrees, south is 180 degrees, and west is 270 degrees. See also... Figure 1 .

[0043] The pipe port number refers to the serial number of the pipe port in the inspection well. Taking the table above as an example, inspection well WS001 is a two-way inspection well, so the two pipe port numbers are WS001-1 and WS001-2. Inspection well WS002 is a three-way inspection well, so the three pipe port numbers are WS002-1, WS002-2, and WS002-3. See the plan view for WS002. Figure 2 .

[0044] This invention proposes a drainage network topology reconstruction method based on geometric constraints. This method utilizes intelligent computer traversal technology to automatically identify and reconstruct network connections. Specifically, starting from any manhole node, the system uses an optimized search algorithm to progressively explore the connections between adjacent manholes based on geometric constraints such as the spatial orientation of the pipe openings, elevation differences, and distance thresholds. During the traversal, each manhole opening number serves as a key, and each opening number is uniquely connected to only one other opening number. When two openings satisfy the geometric matching condition, a topological connection is established, and the matched openings are added to the connected list to avoid redundant calculations. This process is iteratively executed until all opening numbers have been traversed and all connections are determined, ultimately outputting the complete network topology.

[0045] The specific geometric constraints are as follows:

[0046] Constraint 1: Using a specific manhole as the starting point, search for other manholes within a radius R of 200m. Manholes within a radius of 200m are considered potential connecting manholes. The search radius R threshold is adjustable, with a default value of 200m. Convert latitude and longitude to the CGCS2000 geodetic plane rectangular coordinate system, and use a simplified plane approximation method to calculate the distance between two manholes. For example, using WS001 as the starting point with plane rectangular coordinates (X1, Y1), and manhole WS002 with plane rectangular coordinates (X2, Y2), the distance between the two manholes is calculated using the simplified plane approximation method, as follows.

[0047] R² = (X2 - X1)² + (Y2 - Y1)².

[0048] Where X1 and Y1 are the horizontal and vertical coordinates of the current inspection well in the azimuth coordinate system, respectively; X2 and Y2 are the horizontal and vertical coordinates of the potential connecting inspection wells in the azimuth coordinate system, respectively; and R is the distance between the two wells.

[0049] Potential check wells that meet the conditions are found by distance traversal.

[0050] Constraint 2: Using the coordinate relationship between the potential connection inspection well and the current inspection well searched by Constraint 1, according to the principle that the pipe section between two adjacent inspection wells is a straight line and the diameter remains unchanged, calculate the theoretical existing pipe outlet direction angle θtheo. The calculation method of the theoretical pipe outlet direction angle is as follows.

[0051] First, divide the plane of the current inspection well into four quadrants: Quadrant 1 to Quadrant 4, as Figure 3 shown.

[0052] Assume that WS002 is the potential connection inspection well. When X2>X1 and Y2>Y1, WS002 is in the first quadrant; when X2<X1 and Y2>Y1, WS002 is in the second quadrant; when X2>X1 and Y2<Y1, WS002 is in the third quadrant; when X2<X1 and Y2<Y1, WS002 is in the fourth quadrant.

[0053] See Figure 4 , when WS002 is in the first quadrant, the theoretical existing pipe outlet direction angle θtheo is:

[0054] θtheo = arctan[(X1 - X2) / (Y1 - Y2)].

[0055] See Figure 5 , when WS002 is in the second quadrant, the theoretical existing pipe outlet direction angle θtheo is:

[0056] θtheo = 270° + arctan[(Y1 - Y2) / (X1 - X2)].

[0057] See Figure 6 , when WS002 is in the third quadrant, the theoretical existing pipe outlet direction angle θtheo is:

[0058] θtheo = 90° + arctan[(Y1 - Y2) / (X1 - X2)].

[0059] See Figure 7 , when WS002 is in the fourth quadrant, the theoretical existing pipe outlet direction angle θtheo is:

[0060] θtheo = 180° + arctan[(X1 - X2) / (Y1 - Y2)].

[0061] After calculating the theoretical existing pipe outlet direction angle θtheo of WS001 based on the coordinates of WS001 and WS002, query whether the direction angles θ1, θ2, etc. of all pipe outlets in WS001 are approximately equal to θtheo, that is:

[0062] |θX - θtheo| ≤ Δθ.

[0063] Δθ can be set according to the actual direction angle acquisition error, such as 20 degrees.

[0064] When the pipe opening of WS001 has the same direction angle as the theoretical direction angle, then there is a potential connection relationship between WS001 and WS002; otherwise, there is no connection relationship.

[0065] Constraint 3: Based on the direction angle attributes of the potential connection inspection wells searched using Constraint 2 and the current inspection well, according to the principle that the connected direction angles are opposite, further exclude the inspection wells with no connection relationship. See Figure 8 The principle that the connected direction angles are opposite is: when the absolute value of the difference between the direction angles of the pipe openings of two inspection wells is 180 degrees, the two pipe openings are in one pipe segment and are connected.

[0066] Considering the direction angle acquisition error, if the two direction angles satisfy the following relationship, they are judged to be opposite and the pipe openings are connected; otherwise, they are not connected.

[0067] 180° - Δθ ≤ |θ1 - θ2| ≤ 180° + Δθ;

[0068] Δθ is the preset direction angle error threshold, which can be adjusted according to the actual acquisition situation, and the default value is 20 degrees.

[0069] Constraint 4: Based on the pipe diameter data of the potential connection inspection wells searched using Constraint 3 and the current inspection well, according to the principle that the pipe diameters of the connected pipe segments do not change suddenly, further exclude the inspection wells with no connection relationship. The principle that the pipe diameters of the connected pipe segments do not change suddenly is that the pipe diameters are the same when the two pipe openings are connected. When the two pipe diameters are the same, the pipe openings are connected; otherwise, they are not connected.

[0070] Constraint 5: When there is a situation where a certain pipe opening of the current inspection well is connected to multiple other inspection well pipe openings under the condition of satisfying the above four constraints, select the pipe opening with the closest distance as the connected matching pipe opening according to the principle of the closest distance.

[0071] Constraint 6: For the connected matching pipe openings searched under the condition of satisfying the above five constraints, use their pipe bottom elevations and elevation coordinates to judge their upstream and downstream relationships. For example, the WS001-2 pipe opening is connected to the WS002-1 pipe opening. The pipe bottom elevation of the WS001-2 pipe opening is h1-2, and the elevation is H1-2; the pipe bottom elevation of the WS002-1 pipe opening is h2-1, and the elevation is H2-1.

[0072] When H1-2 - h1-2 > H2-1 - h2-1, WS001-2 is the upstream node; when H1-2 - h1-2 < H2-1 - h2-1, WS002-1 is the downstream node.

[0073] When the connection relationships of all the pipe openings of the current inspection well have been determined, according to the law of conservation of mass: inlet mass = outlet mass, when all the pipe openings of this inspection well are all inflows or all outflows, it is prompted that there is an error in the elevation or pipe bottom elevation.

[0074] The computer uses the above six constraints to traverse all manhole openings and automatically outputs a connection relationship table, as shown in the table below. Figure 9 As shown. For unconnected pipe openings that do not meet the constraints, manual verification of the manhole data and connection relationships is required.

[0075] Table 2. Output connection table.

[0076]

[0077] Example 2: This invention proposes a drainage network topology reconstruction system based on geometric constraints, which is described in detail below.

[0078] The system comprises a front-end data acquisition layer, a cloud-based data management and analysis platform layer, and a web application layer. The overall system framework is as follows: Figure 10 As shown.

[0079] The front-end data acquisition layer APP communicates with measuring equipment such as pipe calipers, RTK, sonar scanners, and pipe robots to acquire pipeline data. It also supports manual data entry and transmits the data to the cloud data management and analysis platform layer via a 4G network. The cloud data management and analysis platform layer stores the pipeline network data in a cloud database. The web application layer communicates with the cloud data management and analysis platform layer via the Internet to enable human-computer interaction, allowing for account management, data management, pipeline topology analysis, pipeline data download, GIS interaction, and more.

[0080] The front-end data acquisition layer primarily collects data on the pipes inside the manholes, with each manhole serving as a primary measurement point and each pipe within the manhole as a secondary measurement point. The primary measurement point manhole data mainly includes manhole number, latitude and longitude coordinates, elevation coordinates, upstream and downstream manhole numbers, manhole material, manhole cover shape, manhole cover size, and manhole cover material. The secondary measurement point pipe data within the manhole mainly includes pipe diameter, pipe direction angle, pipe bottom elevation, flow direction, and pipe material.

[0081] The cloud-based data management and analysis platform communicates with the front-end data acquisition layer via 4G to save pipeline network data to a cloud database for easy viewing and analysis by users. Users operate the cloud-based data management and analysis platform through the web application layer, selecting pipeline network engineering data for relevant areas. The platform then performs automatic pipeline network topology analysis using the geometric constraint-based automatic reconstruction method for drainage pipeline network topology proposed in this invention. After analysis, users download the topology file through the web application layer. This topology file contains data files and graphic files; the data files can be directly imported into a GIS platform, and the graphic files provide a direct visual preview of the pipeline network topology connections.

[0082] The system automatically generates the pipeline topology relationship in the following steps:

[0083] Step 1: Through the front-end data acquisition layer APP, the data collected by measuring equipment such as pipe diameter gauges, RTK, sonar scanners, and pipe robots are uploaded to the cloud data management and analysis platform via 4G network.

[0084] Step 2: The cloud-based data management and analysis platform stores the pipeline network data in the cloud database.

[0085] Step 3: The user logs in to the Web application layer with the appropriate permissions.

[0086] Step 4: Users view the pipeline network data through the web application layer and filter out the pipeline network data for the area whose pipeline topology needs to be analyzed.

[0087] Step 5: Click "Automatic Pipeline Topology Analysis." The cloud-based data management and analysis platform will perform topology relationship analysis and reconstruction on the filtered pipeline data. The topology relationship analysis and reconstruction method adopts the automatic reconstruction method for drainage pipeline topology based on geometric constraints proposed in this patent.

[0088] Step 6: Click to preview the generated pipeline topology diagram, and manually review and modify the pipeline topology relationship diagram and unconnected isolated points.

[0089] Step 7: After manual review, click to generate the pipeline topology relationship file, which mainly includes the pipeline topology connection relationship table, pipeline topology map and GIS data interaction file, etc.

[0090] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the invention, based on the technical solution and concept of the invention, should be covered within the scope of protection of the invention.

Claims

1. A method for reconstructing the topology of a drainage pipe network based on geometric constraints, characterized in that, Includes the following steps: Step 1: Construct a manhole attribute table, obtain the attribute data of the manhole and its inlet and load it into the manhole attribute table. The attribute data includes at least spatial coordinates, pipe diameter, orientation angle and pipe bottom elevation. Step 2: Using the current manhole opening as the center, search for potential target manholes within a preset distance threshold range. Establish a coordinate system based on the positional relationship between the current manhole and potential connected manholes, and divide the plane rectangular coordinate system of the current manhole into four quadrants. Step 3: Calculate the distance between the current inspection well and potential connecting inspection wells using the simplified planar approximation method; Step 4: Calculate the theoretical pipe opening direction angle θ of the potential connection inspection wells in each of the four quadrants relative to the current inspection well, and determine whether there is a potential connection inspection well whose measured pipe opening direction angle deviates from the theoretical pipe opening direction angle θ within the allowable error range. Eliminate potential connection inspection wells that exceed the error range. Step 5: For the potential connection manholes screened in Step 4, check the offset relationship between the direction angle of the current manhole opening and the direction angle of the potential connection manhole opening. Determine if the sum of the two direction angles is complementary within the error range. If the offset relationship cannot be satisfied, then exclude the potential connection manhole opening. Step 6: For the potential connection inspection wells screened in Step 5, determine whether the pipe diameters of the current inspection well and the potential connection inspection wells are the same or within the allowable error range. If they are inconsistent, the potential connection inspection well is excluded. Step 7: If a certain pipe opening of the current inspection well corresponds to multiple potential connected inspection well pipe openings after step 6, then select the pipe opening closest to it as the connected matching pipe opening; Step 8: Determine the upstream and downstream relationship based on the bottom elevation and upper elevation of the connected matching pipe openings; Step 9: Traverse all manhole openings and output the connection relationship table. Unconnected openings that do not meet the above geometric constraints need to be manually confirmed and corrected. Step 10: Store the reconstructed pipeline network topology as data files and graphic files. Data files can be directly imported into the GIS platform, and graphic files can be directly used for visual preview of pipeline network topology connections.

2. The drainage pipe network topology reconstruction method based on geometric constraints as described in claim 1, characterized in that, The directional angle is defined as follows: with the geomagnetic direction as a reference, due north is defined as 0 degrees, and the angle increases sequentially in a clockwise direction, with due east being 90 degrees, due south being 180 degrees, and due west being 270 degrees.

3. The drainage pipe network topology reconstruction method based on geometric constraints as described in claim 1, characterized in that, Step 1 includes: defining a manhole attribute table, which includes manhole number, pipe opening number, longitude coordinates, latitude coordinates, high-rise coordinates, measured pipe diameter, designed pipe diameter, direction angle, pipe bottom elevation, upstream manhole number, downstream manhole number, manhole material, manhole cover shape, manhole cover size, manhole cover material, and pipe material.

4. The drainage pipe network topology reconstruction method based on geometric constraints as described in claim 1, characterized in that, Step 2 includes: The division of the four quadrants is defined as follows: with the current inspection well as the origin, a plane rectangular coordinate system is established, with two mutually perpendicular coordinate axes, the X-axis and the Y-axis, the positive direction of the X-axis pointing to the magnetic east direction and the positive direction of the Y-axis pointing to the magnetic north direction. Let the coordinates of the origin of the coordinate axis be (X1, Y1), and the coordinates of the potential connection manhole be (X2, Y2). When the coordinates of the potential connection manhole satisfy X2 > X1 and Y2 > Y1, the potential connection manhole is located in the first quadrant; when X2 < X1 and Y2 > Y1, the potential connection manhole is located in the second quadrant; when X2 > X1 and Y2 < Y1, the potential connection manhole is located in the third quadrant; and when X2 < X1 and Y2 < Y1, the potential connection manhole is located in the fourth quadrant. X1 and Y1 are the horizontal and vertical coordinates of the current inspection well in the azimuth coordinate system, respectively, while X2 and Y2 are the horizontal and vertical coordinates of the inspection wells of the potential connected objects in the azimuth coordinate system, respectively.

5. The drainage pipe network topology reconstruction method based on geometric constraints as described in claim 1, characterized in that, Step 3 includes: calculating the distance between the current inspection well and the potential connecting inspection wells using a simplified plane approximation method, the calculation formula being: R² = (X² - X¹)² + (Y² - Y¹)²; Where X1 and Y1 are the horizontal and vertical coordinates of the current inspection well in the azimuth coordinate system, respectively; X2 and Y2 are the horizontal and vertical coordinates of the potential connecting inspection wells in the azimuth coordinate system, respectively; and R is the distance between the two wells.

6. The drainage network topology reconstruction method based on geometric constraints as described in claim 1, characterized in that, Step 4 includes: calculating the theoretical nozzle orientation angle θ of the potential connection inspection well relative to the current inspection well. The calculation method is as follows: When the potential connection check well is in the first quadrant, θtheoretical = arctan[(X1-X2) / (Y1-Y2)]; When the potential connection check well is in the second quadrant, θtheoretical = 270° + arctan[(Y1-Y2) / (X1-X2)]; When the potential connection check well is in the third quadrant, θtheoretical = 90° + arctan[(Y1-Y2) / (X1-X2)]; When the potential connection check well is in the fourth quadrant, θtheoretical = 180° + arctan[(X1-X2) / (Y1-Y2)]; Where X1 and Y1 are the horizontal and vertical coordinates of the current inspection well in the azimuth coordinate system, respectively, and X2 and Y2 are the horizontal and vertical coordinates of the potential connecting inspection well in the azimuth coordinate system, respectively. Determine whether there exists an actual pipe opening direction angle in the current inspection well that satisfies |θX-θthen|≤Δθ. If so, proceed to step 5; otherwise, exclude the potential connection inspection well. Here, θX is the actual pipe opening direction angle in any current inspection well, and Δθ is a preset direction angle error threshold.

7. The drainage pipe network topology reconstruction method based on geometric constraints as described in claim 1, characterized in that, Step 5 includes: For each opening of the current inspection well, its theoretical direction angle relative to the geomagnetic north is denoted as θ1; for each opening of a potential connecting inspection well, its theoretical direction angle relative to the geomagnetic north is denoted as θ2. Set Δθ as a preset direction angle error threshold; if |θ1-θ2| is within the interval [180°-Δθ, 180°+Δθ], then determine that the pipe opening of the potential connection inspection well and the pipe opening of the current inspection well satisfy the direction angle reverse constraint, and proceed to step 6; otherwise, exclude the potential connection inspection well.

8. The drainage pipe network topology reconstruction method based on geometric constraints as described in claim 1, characterized in that, Step 8 includes: judging the upstream and downstream relationship based on the bottom elevation and top elevation of the connected matching pipe openings. If H1 - h1 > H2 - h2, the pipe opening of the current inspection well is the upstream node; if H1 - h2 < H2 - h2, the pipe opening of the current inspection well is the downstream node, where H1 and h1 are respectively the top elevation and bottom elevation of the current inspection well, and H2 and h2 are respectively the top elevation and bottom elevation of the potential connected inspection well.

9. A drainage pipe network topology reconstruction system based on geometric constraints, characterized in that, It includes a front - end data acquisition layer, a cloud - based data management and analysis platform layer, and a Web application layer; The front - end data acquisition layer includes an APP. The APP communicates with a pipe diameter measuring instrument, RTK, a sonar scanner, and a pipeline robot to obtain pipeline data information, and also supports manual input of data information, and transmits the data to the cloud - based data management and analysis platform layer through a 4G network; The cloud - based data management and analysis platform layer includes a cloud server and a cloud database, which are used to store and manage pipe network data; The Web application layer communicates with the cloud - based data management and analysis platform layer to implement account management, data management, pipe network topology analysis, data download, and GIS interaction; The pipe network topology analysis adopts the method described in any one of claims 1 to 8.

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