Transmission line engineering route selection method and system based on road network projection algorithm

Abstract

The application relates to the technical field of power transmission line engineering route selection, and provides a power transmission line engineering route selection method and system based on a road network projection algorithm, which comprises the following steps: establishing a direct connection line from a source point to a target point, establishing an effective space area for power transmission line engineering route selection based on the direct connection line, then performing equidistant interval projection line drawing on the direct connection line in the effective space area, and realizing road network projection and virtual node modeling; obtaining a plurality of adjacent connecting edges as virtual road sections based on the virtual nodes established on adjacent projection points on the direct connection line; obtaining a plurality of same-position connecting edges as virtual road sections based on the virtual nodes established on the same projection points on the direct connection line; and obtaining the power transmission line engineering route selection result by adopting a bidirectional Dikkstra algorithm based on all virtual road sections and corresponding virtual road section cost functions. The application can automatically generate virtual nodes in an existing road network for any source and terminal point, and can generate a path meeting actual traffic conditions in real time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission line engineering route selection, and particularly relates to a power transmission line engineering route selection method and system based on a road network projection algorithm. BACKGROUND

[0002] Line planning, as a key link in many engineering applications, is self-evident in its importance, and plays an important role in many fields including power transmission line selection, oil and gas transmission, water conservancy line engineering planning, etc. Through scientific line planning, the design requirements and safe production of engineering projects can be realized, engineering costs can be reduced, and resource utilization can be improved. Road network is an important infrastructure condition often used by engineering construction, and in line planning, to improve the convenience of engineering construction and post-maintenance, and to make full use of the infrastructure conditions of the existing road network, it is an important constraint condition. Such line planning is based on the existing road network, and needs to combine its business to optimize the layout of line nodes and the direction of the line. Node setting is the core link of the planning process, for example, in power transmission line planning, power transmission towers are required to be set at certain intervals along the road to connect the power transmission lines and ensure the stability and safety of power transmission. The above engineering line planning needs to consider multiple constraint factors and use GIS spatial optimization methods to realize reasonable layout of the line.

[0003] The main algorithms for line planning based on connected networks or rules include Dijkstra algorithm, genetic algorithm, ant colony algorithm, artificial potential field, etc., and are applied in different path planning scenarios. Dijkstra algorithm is a classic algorithm for solving the shortest path problem due to its high efficiency and accuracy. Genetic algorithm simulates the biological evolution process to realize global search and optimization, and is suitable for handling large-scale, multi-objective line planning problems. Ant colony algorithm is inspired by the foraging behavior of ants, and guides path selection through pheromone accumulation and updating, with self-organizing ability and robustness characteristics. Deep reinforcement learning technology combines the advantages of deep learning and reinforcement learning, and optimizes the decision-making strategy through the interaction between the agent and the environment, showing strong ability in path planning. Artificial potential field method introduces the concepts of gravitational and repulsive fields in path planning to plan a reasonable line, and has the characteristics of easy understanding and implementation. In addition, particle swarm optimization, dynamic window method, probabilistic roadmap (PRM), rapidly-exploring random tree (RRT), visibility graph algorithm, etc. are also widely used in line planning.

[0004] The above space communication rule or network can be expressed based on a grid-based route planning model and a connection graph-based model. The grid-based route planning model divides the space into a series of regular or irregular grids, and achieves the planning goal by finding a connected path in the grid. The grid method is simple and intuitive, and is suitable for complex application scenarios such as robot walking and indoor navigation, where the road network is connected incompletely and there are path obstacles. However, for engineering route planning, there is a balance problem between the calculation accuracy and efficiency of the subsequent implementation algorithm. When the grid is too large, the accuracy of the planned route result is low, and it is difficult to match the existing road network, resulting in a large amount of subsequent processing workload. When the grid is set too small, the data storage and calculation amount will increase significantly. The connection graph-based route planning model describes the path by establishing nodes and node connection networks in the target space, and solves the problem by using graph algorithms. This method can more accurately match the actual situation of the road network path, but it has the problem of incomplete route connection, especially in the case of sparse road network, which may cause node connection interruption and route planning failure. Another problem of the graph-based method is that it depends on the preprocessed road topology network. When the road network changes or the road attribute changes, the road network relationship needs to be rebuilt to support the implementation of the route planning algorithm.

[0005] Engineering route planning, including power transmission lines, is a complex optimization problem. The optimization of route node layout and its connection is closely related to the engineering effectiveness and cost. Among them, the full use of road infrastructure sets the route node close to the road network, and designs the route connection and direction based on the route node to reduce the overall construction cost. Therefore, it is necessary to design a model and a calculation method to find the node selection that meets the constraint condition. In reality, the road network is often not connected, that is, there may be no connection path between different roads, or there may be a lot of detours in the case of connection, which poses a challenge to the route planning algorithm. In addition, the node connection modeling in the traffic network graph is usually based on the connection relationship between the head and tail nodes or the intersection nodes of the road segments to establish a network topology relationship graph. However, when using traffic infrastructure for engineering route planning, it is necessary to flexibly connect the intermediate nodes or non-intersection nodes on different road segments to support the network connection across the non-intersection or non-head and tail points of the road. Therefore, the existing traffic road network topology modeling method cannot support engineering route planning.

[0006] Transmission line engineering also places greater demands on dynamic line planning. For example, in the planning of some obstacle avoidance lines, the appearance of obstacles is random, requiring dynamic implementation capabilities for line planning modeling and calculation. Currently, dynamic programming algorithms mainly address changes in obstacles, with less focus on the dynamic changes in the road network itself. When the road network changes, it is necessary to reconstruct the topological relationships of network nodes and connectivity based on the road network. To support dynamic changes in the road network, incremental graph construction is used, but dynamically maintaining the data graph imposes an additional burden on the algorithm itself. Summary of the Invention

[0007] The purpose of this invention is to solve at least one technical problem in the background art and to provide a method and system for selecting the route of power transmission line projects based on road network projection algorithm.

[0008] To achieve the above objectives, this invention provides a method for selecting the route of power transmission line projects based on a road network projection algorithm, comprising:

[0009] Establish a direct connection from the source point to the target point, dynamically establish an effective spatial area for the selection of transmission line engineering based on the direct connection, and then draw equidistant projection lines on the direct connection within the effective spatial area to realize road network projection and virtual node modeling.

[0010] Multiple adjacent connected edges are obtained as virtual road segments based on virtual nodes established on adjacent projection points on the direct connection line, and multiple co-located connected edges are obtained as virtual road segments based on virtual nodes established on the same projection point on the direct connection line.

[0011] Based on all virtual road segments and their corresponding cost functions, the bidirectional Dikkstra algorithm is used to calculate the route selection results for the transmission line project.

[0012] According to one aspect of the present invention, establishing a direct connection from the source point to the target point, establishing an effective spatial region for power transmission line engineering route selection based on the direct connection, and then, within the effective spatial region, performing equidistant projection lines on the direct connection to realize road network projection and virtual node modeling, includes:

[0013] Establish a straight line from the source point to the target point, determine the maximum acceptable spatial range of the line selection, generate a rectangular buffer range on both sides of the straight line with a preset parameter size, and use the four corner points of the rectangle to represent the effective spatial area allowed by the line selection result.

[0014] Insert n equally spaced road projection points, including the source point and the target point, on the straight line;

[0015] For each road projection point, a projection line perpendicular to the straight line is drawn. Any projection line has multiple intersection points with the road network within the effective space area. Each intersection point is a virtual node. If two virtual nodes correspond to the same road projection point, the two virtual nodes are co-located. If two virtual nodes belong to two adjacent road projection points, the two virtual nodes are adjacent.

[0016] According to one aspect of the present invention, multiple adjacent connected edges serving as virtual road segments are obtained based on virtual nodes established on adjacent projection points on a straight line, and multiple co-located connected edges serving as virtual road segments are obtained based on virtual nodes established on the same projection point on a straight line, including:

[0017] Based on the order of road projection points, adjacent connected edges between virtual nodes under two adjacent road projection points and co-located connected edges between virtual nodes under the same road projection point are established, and each adjacent connected edge and co-located connected edge is used as a virtual road segment.

[0018] The total number of virtual road segments is:

[0019] ;

[0020] in, There exists a relationship between the projection line drawn on n equidistant road projection points on a straight line within the effective spatial area and the road network. The total number of virtual road segments when there are virtual nodes. The dot in This indicates that the number of virtual nodes differs depending on the order in which they are ordered. This is the upper limit of the adjacent connected edges between virtual nodes established based on the order relationship between road projection point i and its adjacent road projection point i+1 within the effective spatial area. A virtual node is established at road projection point i within the effective spatial area.

[0021] According to one aspect of the present invention, based on the virtual road segment and the corresponding cost function of the virtual road segment, the method includes:

[0022] For any virtual road segment, calculate the total road segment cost, including the distance between one virtual node and another, and the cost coefficient *pl* for traversing terrain and obstacles. The cost function is calculated by integrating and summing the product of the distance and the cost coefficient.

[0023] ;

[0024] in, and These are two adjacent virtual nodes. To from virtual nodes arrive A segment of a virtual road that traverses various types of terrain and obstacles. Virtual road segment The spatial distance of the segment s, The cost coefficient is determined by three types of characteristic factors: the distance between the area s spans and the road network, the topographic features, and the types of obstacles.

[0025] in,

[0026] In the formula, Let h be the penalty weight for the h-th land use type, and m be the total number of land use types.

[0027] To achieve the above objectives, the present invention also provides a transmission line engineering route selection system based on a road network projection algorithm, comprising:

[0028] The road network projection and virtual node construction module establishes a direct connection from the source point to the target point, dynamically establishes an effective spatial area for power transmission line engineering route selection based on the direct connection, and then performs equidistant projection lines on the direct connection within the effective spatial area to realize road network projection and virtual node modeling.

[0029] The connected edge acquisition module obtains multiple adjacent connected edges as virtual road segments based on virtual nodes established on adjacent projection points on the straight line, and obtains multiple co-located connected edges as virtual road segments based on virtual nodes established on the same projection points on the straight line.

[0030] The route selection result calculation module uses the bidirectional Dikkstra algorithm, based on all virtual road segments and the cost function of the corresponding virtual road segments, to calculate the route selection result of the transmission line project.

[0031] To achieve the above objectives, the present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the transmission line engineering route selection method based on the road network projection algorithm as described above.

[0032] To achieve the above objectives, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the transmission line engineering route selection method based on the road network projection algorithm as described above.

[0033] According to the present invention, for any source and destination, the present invention automatically generates virtual nodes in the existing road network and generates a path that conforms to the actual traffic conditions in real time.

[0034] The path generation process simultaneously optimizes both "short crossing distance" and "low construction cost" by converting distance, terrain, obstacles, and other factors into quantifiable indicators through a unified cost function.

[0035] Regardless of whether the road network is connected, this invention can provide a power transmission line solution that is "convenient to construct and has the lowest cost".

[0036] According to the above-described scheme of the present invention, the present invention innovatively introduces the idea of ​​"segmented reachability": it is only necessary to ensure that each tower position is reachable from its nearest road node (virtual node), without the need for direct road connections between tower positions, thereby transforming "road network disconnection" into "local reachability" and getting rid of the topological connectivity requirements of many path planning algorithms. Attached Figure Description

[0037] Figure 1 A flowchart illustrating a method for selecting the route of a power transmission line project based on a road network projection algorithm according to an embodiment of the present invention;

[0038] Figure 2a This is a diagram of the non-connected road network from Example 1.

[0039] Figure 2b This is a connectivity road network diagram for Example 1;

[0040] Figure 3 This is a schematic diagram illustrating the modeling principle of a non-connected network in Example 1.

[0041] Figure 4 This is a flowchart illustrating the method for calculating the penalty coefficient in Example 1. Detailed Implementation

[0042] The invention will now be discussed with reference to exemplary embodiments. It should be understood that the described embodiments are merely intended to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0043] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment".

[0044] Figure 1 The flowchart schematically illustrates a method for selecting the route of a power transmission line project based on a road network projection algorithm according to an embodiment of the present invention. Figure 1 As shown, in this embodiment, the transmission line engineering route selection method based on the road network projection algorithm includes:

[0045] For a given route selection target from the source point to the target point, establish a direct line from the source point to the target point, establish an effective spatial area for the route selection of the transmission line project based on the direct line, and then draw equidistant projection lines on the direct line within the effective spatial area to realize road network projection and virtual node modeling.

[0046] Multiple adjacent connected edges are obtained as virtual road segments based on virtual nodes established on adjacent projection points on the direct connection line, and multiple co-located connected edges are obtained as virtual road segments based on virtual nodes established on the same projection point on the direct connection line.

[0047] Based on all virtual road segments and their corresponding cost functions, the bidirectional Dikkstra algorithm is used to calculate the route selection results for the transmission line project.

[0048] Furthermore, according to one embodiment of the present invention, a direct connection line from the source point to the target point is established, an effective spatial region for power transmission line engineering route selection is established based on the direct connection line, and then, within the effective spatial region, equidistant projection lines are drawn on the direct connection line to realize road network projection and virtual node modeling, including:

[0049] Establish a straight line from the source point to the target point, determine the maximum acceptable spatial range of the line selection, generate a rectangular buffer range on both sides of the straight line with a preset parameter size, and use the four corner points of the rectangle to represent the effective spatial area allowed by the line selection result.

[0050] Insert n equally spaced road projection points, including the source point and the target point, on the straight line;

[0051] For each road projection point, a projection line perpendicular to the straight line is drawn. Any projection line has multiple intersection points with the road network within the effective space area. Each intersection point is a virtual node (the spatial location point where the candidate station tower is located). If two virtual nodes correspond to the same road projection point, the two virtual nodes are in the same position. If two virtual nodes belong to two adjacent road projection points, the two virtual nodes are in the adjacent position.

[0052] Furthermore, according to one embodiment of the present invention, multiple adjacent connected edges serving as virtual road segments are obtained based on virtual nodes established on adjacent projection points on the direct connection line, and multiple co-located connected edges serving as virtual road segments are obtained based on virtual nodes established on the same projection point on the direct connection line, as follows:

[0053] Based on the order of road projection points, adjacent connected edges between virtual nodes under two adjacent road projection points and co-located connected edges between virtual nodes under the same road projection point are established, and each adjacent connected edge and co-located connected edge is used as a virtual road segment.

[0054] The total number of virtual road segments is:

[0055] ;

[0056] in, There exists a relationship between the projection line drawn on n equidistant road projection points on a straight line within the effective spatial area and the road network. The total number of virtual road segments when there are virtual nodes. The dot in This indicates that the number of virtual nodes differs depending on the order in which they are ordered. This is the upper limit of the adjacent connected edges between virtual nodes established based on the order relationship between road projection point i and its adjacent road projection point i+1 within the effective spatial area. This refers to a virtual node established at road projection point i within the effective spatial area. In this embodiment, the symbol... This means that the value of q will vary depending on the value of i.

[0057] Furthermore, according to one embodiment of the present invention, the cost function based on the virtual road segment and the corresponding virtual road segment includes:

[0058] For any virtual road segment, calculate the total road segment cost, including the distance between one virtual node and another, and the cost coefficient *pl* for traversing terrain and obstacles. The cost function is calculated by integrating and summing the product of the distance and the cost coefficient.

[0059] ;

[0060] in, and These are two adjacent (same position or adjacent position) virtual nodes. To from virtual nodes arrive A segment of a virtual road that traverses various types of terrain and obstacles. Virtual road segment The spatial distance of the segment s, The cost coefficient is determined by three types of characteristic factors: the distance between the area s spans and the road network, the topographic features, and the types of obstacles.

[0061] in,

[0062] In the formula, Let h be the penalty weight for the h-th land use type, and m be the total number of land use types.

[0063] In this embodiment, the bidirectional Dikkstra algorithm calculates the shortest path based on Dikkstra's algorithm from both the starting point and the ending point. The algorithm terminates when overlapping virtual nodes are found in both directions.

[0064] According to the above-described scheme of the present invention, the present invention automatically generates virtual nodes in the existing road network for any source and destination, and generates a path that conforms to the actual traffic conditions in real time.

[0065] The path generation process simultaneously optimizes both "short crossing distance" and "low construction cost" by converting distance, terrain, obstacles, and other factors into quantifiable indicators through a unified cost function.

[0066] Regardless of whether the road network is connected, this invention can provide a power transmission line solution that is "convenient to construct and has the lowest cost".

[0067] According to the above-described scheme of the present invention, the present invention innovatively introduces the idea of ​​"segmented reachability": it is only necessary to ensure that each tower position is reachable from its nearest road node (virtual node), without the need for direct road connections between tower positions, thereby transforming "road network disconnection" into "local reachability" and getting rid of the topological connectivity requirements of many path planning algorithms.

[0068] Furthermore, to achieve the above objectives, the present invention also provides a transmission line engineering route selection system based on a road network projection algorithm, comprising:

[0069] The road network projection and virtual node construction module establishes a direct connection from the source point to the target point, dynamically establishes an effective spatial area for power transmission line engineering route selection based on the direct connection, and then performs equidistant projection lines on the direct connection within the effective spatial area to realize road network projection and virtual node modeling.

[0070] The connected edge acquisition module obtains multiple adjacent connected edges as virtual road segments based on virtual nodes established on adjacent projection points on the straight line, and obtains multiple co-located connected edges as virtual road segments based on virtual nodes established on the same projection points on the straight line.

[0071] The route selection result calculation module uses the bidirectional Dikkstra algorithm, based on all virtual road segments and the cost function of the corresponding virtual road segments, to calculate the route selection result of the transmission line project.

[0072] The transmission line engineering route selection system based on the road network projection algorithm of the present invention can realize the transmission line engineering route selection method based on the road network projection algorithm. The specific process steps are as described above and will not be repeated here.

[0073] Furthermore, to achieve the above objectives, the present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the transmission line engineering route selection method based on the road network projection algorithm as described above.

[0074] Furthermore, to achieve the above objectives, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the transmission line engineering route selection method based on the road network projection algorithm as described above.

[0075] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely one preferred embodiment of the invention and are only used to explain the invention. They do not limit the scope of protection of the invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0076] Example 1

[0077] The method for selecting the route of transmission line projects based on road network projection algorithm includes the following steps:

[0078] Step 1: Road network projection and virtual node modeling:

[0079] Define G(R, E) as a network graph built based on road network infrastructure and projection algorithms, where R represents the set of virtual nodes on the road network RD, and E represents the set of virtual connectivity relationships (edges) between virtual nodes. A virtual node is defined by its projection point number i and the numbers j arranged from top to bottom at that projection point, i.e., R... i,j ∈R, for any two virtual nodes R i1,j1 R i2,j2 ∈R and R i1,j1 →R i2,j2 If ∈E, then R is called i1,j1 and R i2,j2 It has a connection relationship, and the distance (R) between the connecting edges is specified. i1,j1 →R i2,j2 )≥0. Specifically, the connection relationships between virtual nodes are defined to be bidirectional, i.e., R ≥ 0. i1,j1 →R i2,j2 ∈R⇔ R i2,j2 →R i1,j1 ∈R, distance(R) i1,j1 →R i2,j2 )=distance(R i2,j2 →R i1,j1 It also stipulates that the same virtual node has a distance of 0, i.e., distance(R) i,j →R i,j =0. For any R i1,j1 R i2,j2 ∈R, if R i1,j1 →Ri2,j2 ∉ E, then distance(R i1,j1 → R i2,j2 ) = ∞. In this embodiment, without special requirements, |i1 - i2| = 1 or |j1 - j2| = 1 is satisfied, that is, R i1,j1 and R i2,j2 are adjacent or in the same position based on the projection points.

[0080] For example, Figure 2a in the road network shown in, assuming that there are connecting edges for S (source point) → 1, 7 → T (target point), there is no reachable path from S → T, but virtual road segments can be defined for the virtual nodes 2 → 3 and 4 → 5, and distance(2, 3) and distance(4, 5) are positive real numbers, then a non-directly connected path S → 1 → 2 → 3 → 4 → 5 → 6 → 7 → T can be generated; in Figure 2b , assuming that there are connecting edges for S → 1, S → A, 4 → T, F → T, then there are both connected paths and non-connected paths from S to T. Among them, S → 1 → 2 → 3 → 4 → T has path connectivity, but the cost of the connected path d(S → 1 → 2 → 3 → 4 → T) is large, so it is called a non-optimized connected path. Although there is no direct connection path for S → A → B → C → D → E → F → T, if virtual road segments B → C and D → E can be redefined based on the transmission line engineering business rules, such that the cost of the path without a direct connection d'(S → A → B → C → D → E → F → T) < d opt (S → T), then d'(S → T) is a non-connected optimized path, where d opt (S → T) is the minimum cost value for the S → T connection that can be found based on the existing road network.

[0081] On the Cartesian two-dimensional coordinate system, there is a road network RD. From any source point S in space to the target point T, for a node sequence S → T = {S → R 2,. , R 2,. → R 3,. , …, R n-2,. → R n-1,. , R n-1,. → T} and the straight-line distance d(R i,j , RD) of any node R i,j from the road RD is < t, where t is a positive real number, and there is a sequence of non-connected adjacent nodes R i,. and R i+1,. except for the connecting edge between S and T, that is, R i,. and R i+1,. cannot be connected by the road network anyway, then S → T is a non-connected path with respect to the road network RD.

[0082] Route planning based on road network RD aims to find a virtual node sequence R from the source point S to the target point T. i,. →R i+1,. A connected set, requiring distance(R) i,. →R i+1,. )≤dis, and any virtual node R i,j The straight-line distance from the road network does not exceed t, satisfying the condition that d(S→T) is minimized. t typically represents the maximum transportation distance in the route planning and construction project, and dis represents the maximum spatial distance between adjacent virtual nodes according to business rules. For convenience, this embodiment sets t=0, meaning it considers virtual nodes to fall on roads. In a disconnected network, this means that distance(R) exists. i,. →R i+1,. Since )=∞, the connectivity objective cannot be satisfied. Therefore, a set of road projection points pi is defined, which are ordered discrete points generated at equal intervals dis on the straight line L with S as the source and T as the destination. The set of projection points P can be represented as: P={pi|i=1,…, n}, where i represents the number of the projection point;

[0083] Where p1 coincides with the source point S, pn coincides with the target point T, and i represents the node division on the straight line L with p1 as the source point and pn as the target point according to certain rules. Each node corresponds to the projection of a road point on the planned route Path onto L. Including the source point and the target point, the number of projection points n = length(L) / dis + 1, where length(L) is the length of the line segment L, and the spacing threshold parameter dis is determined according to the business application rules. Taking all projection points pi (i=1,…, n) as the positioning basis, the straight line passing through pi and perpendicular to L is called the perpendicular line li of the projection point (road projection point) pi on L. Then the set LV of li is represented as: LV={li|i=1,…, n};

[0084] Considering the scope of the study area, when planning the route, road points are not allowed to be too far from the straight line L. Assume that the area is restricted to the buffer zone Buff on both sides of the straight line L, with a distance of b=f*length(L). The coefficient f is called the visual scale coefficient of the algorithm for planning the route. Usually, 1>f>0.5, that is, the road network beyond the Buff range is not considered, and li is cut off as the line segment within the Buff.

[0085] For any vertical line li at the projection point pi of a road, the intersection point with the road network within Buff is called a virtual road point (virtual node), denoted by j from top to bottom (or bottom to top) (virtual nodes are denoted by j, and i represents the order of the projection points; at the same projection point, the corresponding projection line has q.(i) intersection points with the road network, and these intersection points are all virtual nodes; here, j is the virtual node generated at projection point i, denoted by j=1,2,…,q.(i) from top to bottom), and j≤ q.(i), where q.(i) is a function based on i, indicating that the number of intersection points between the vertical line li and the road lines is different at different projection points pi. Let R represent the set of all candidate virtual road points for L as: R={R i,j |i=1,…,n; j=1,…,q.};

[0086] Figure 3 This illustrates the principle of non-connected network modeling. From the source point S to the target point T, no direct path can be found directly from the road network. However, through non-connected network modeling, virtual nodes and virtual road segments can be easily generated, thus establishing a non-connected path. The direct line L from the source point S to the target point T is divided by a spacing dis to determine the set of road projection points P. The projection of the road network onto the road projection point pi is represented by the virtual road points where the perpendicular line li passing through pi and perpendicular to L intersects the road, considering only the space defined by the buffer buff. A virtual edge is established between corresponding virtual road points on two adjacent projection points. This is called an adjacency connection (adjacency connected edge). Adjacent virtual road points on the same projection point establish a virtual connection edge. This is called co-location. In a special case, if no co-location exists at any projection point pi... Then, the projection points before and after can establish virtual connection edges across layers, that is... .

[0087] Step 2: Create a virtual road segment:

[0088] A planned route Path can be represented as edges e that have an ordered relationship, i.e., Path =<e1,e2,…,el> any element e in Path f ∈E, by tuple <id,R x1 ,y1,R x2 Composed of y2,cost>, with id as e f The unique identifier, R x1,y1 R x2,y2 e f The start and end nodes (virtual nodes) have a cost of e. f The connectivity cost, and the path R between nodes x1,y1 →R x2,y2It depends on the spatial region traversed. For adjacent elements e f and e f+1 The ending node of the former is the starting node of the latter. To ensure that the planned route has the lowest possible construction cost, a penalty is applied to the connecting edges, defining a penalty coefficient pl (pl>1). The cost of node connection is calculated based on the formula:

[0089] ;

[0090] in, Indicates the node R x1,y1 To R x2,y2 Because it crosses different road network buffer zones, topographic features, and obstacle areas s, it is divided into several road segment intervals, and different intervals s have different lengths (ds) and penalty coefficients (pls). That is, the penalty coefficient calculation takes into account buffer zones of different scales (buffer sizes) of the road network, topographic features (such as slope and elevation), and different types of obstacles (such as farmland, ecological protection areas, wind zones, ice zones, etc.), and the method is as follows: Figure 4 The penalty weight wgt0 is set for buffers of different scales (buffer sizes) of the road network to ensure that the selection of virtual nodes and virtual road segments is as close as possible to the road network (with smaller values). Finally, the wgt values ​​defined by different layer elements are summarized to form pls.

[0091] Based on the set R of candidate road points (virtual road points), the algorithm for constructing connectivity between road points is defined by Algorithm 1 in Table 1 below. Lines 3-5 utilize the neighbor order relationship of the road projection points corresponding to the road points (i.e., Ri,.→Ri+1,.), ensuring at most q.(i)×q.(i+1) neighbor connected edges. This guarantees that a connected path can be found from the source point S to the target point T. Simultaneously, the connection order constraint of neighbor projected points avoids a large number of invalid connections, ensuring a moderate network size. Line 6 ensures that road points are only connected at the same projection point pi without crossing or traversing connections, with at most q.(i)-1 (q.(i)≥1) same-position connected edges, again avoiding excessive invalid connections. Lines 9-22 guarantee connectivity for unconnected nodes, enabling the establishment of cross-neighbor virtual connections between road points even without a road network. The complexity of the algorithm is determined by the number of road projection points (n) and the number of intersections between the perpendicular line li of each projection point pi on L and the road line (i.e. q.(i)). If n ≫ q.(i), the number of connecting edges is related to n and q.(i). Assuming the average value of q.(i) is q, the number of edges is proportional to n×q2. Assuming the length of the direct connection line L is 150km, the spacing dis determined by the business rules is 1.5km, and within the search space (i.e., the buffer Buff), the number of projection points is 100, and the average number of intersection points (q.(i)) between the projection points li and the road lines is 5, then the number of dynamically constructed candidate road points is 100×5=500. The number of connecting edges of road points located at different projection points and connected by the candidate road points is 100×5×5=2500, and the number of connecting edges of road points located at the same projection point and connected by the candidate road points is 100×4, for a total of 2900 edges.

[0092] Table 1. Virtual Node and Connected Graph Modeling Algorithm

[0093]

[0094] Since the source point S and the destination point T may not be on the road network, they need to be added to the aforementioned road points and connecting road segments. For any R i,j ∈R, if distance(R) i,j ,S)>distance(R i,j If T), then add R. i,j Otherwise, add a connected edge between T and R. i,j The connecting edge between S and T. In Algorithm 1, lines 23-31 add the source point S and the target point T to the road network.

[0095] Considering the practical application scenarios of power transmission line projects, the node connections constructed by Algorithm 1 all allow bidirectional connections, that is, if R x1,y1 To Rx2,y2 If there is connectivity, then R x2,y2 To R x1,y1 They also have connectivity, and the cost of connectivity is the same (distance).

[0096] Step 3: Calculate the route ST.

[0097] A bidirectional Dijkstra's algorithm is employed, based on road infrastructure conditions and projection modeling methods, to address the dynamic planning requirements of engineering routes. Dijkstra's algorithm is a classic algorithm for shortest path analysis, with a time complexity of O((|R|+|E|)log|R|). In sparse graphs, a bidirectional Dijkstra's algorithm is preferable, as its time complexity is only O(|R|log|R|+|E|), where |V| represents the number of nodes (virtual road points), and |E| represents the number of connected road segments between nodes. In the modeling of virtual nodes and connected graphs, the generated road segment topology is a typical sparse graph; therefore, a bidirectional Dijkstra's algorithm is used.

[0098] Table 2 Road node connectivity relationship Dijkstra's algorithm

[0099]

[0100] For the set of road nodes R (including start and end nodes S and T) and the set of edges E, find the optimal planned route from the source node S to the target node T. The output is the path that can cross multiple road nodes, and the distance d(T) from S to T. In Dijkstra's algorithm (Algorithm 2), lines 1-5 initialize the algorithm by setting the initial shortest distance between all virtual nodes and other nodes to infinity, and the distance of the source node S to 0. Unvisited nodes are managed using a priority queue. Lines 6-20 iterate through the algorithm by extracting the node u with the smallest distance d[u] from the queue Q using the extract_min function and updating the information of all neighbor nodes v of u. Lines 21-26 reconstruct the path by tracing back from the target node T using the stored predecessor node information to construct the shortest path. The implementation of the bidirectional Dijkstra's algorithm is based on Dijkstra's algorithm. Since Dijkstra's algorithm is essentially a single-source shortest path algorithm, only the source node is required as input. Thus, the forward operation starts from the source node S, and the reverse operation starts from the target node T, performing synchronous or cross-operation. When the visited nodes overlap in the two directional operations, a path connecting S and T is found. Compared to unidirectional search, the bidirectional search has a smaller search space.

[0101] Those skilled in the art will recognize that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0102] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and equipment can be referred to the corresponding process in the foregoing method implementation, and will not be repeated here.

[0103] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0104] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0105] In addition, the functional modules in the embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0106] If the aforementioned functions are implemented as software functional modules 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 this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the sending / receiving methods of various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0107] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

[0108] It should be understood that the sequence number of each step in the invention and its embodiments does not absolutely imply 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.

Claims

1. A method for selecting the route of transmission line projects based on road network projection algorithm, characterized in that, include: Establish a direct connection from the source point to the target point, dynamically establish an effective spatial area for the selection of transmission line engineering based on the direct connection, and then draw equidistant projection lines on the direct connection within the effective spatial area to realize road network projection and virtual node modeling. Multiple adjacent connected edges are obtained as virtual road segments based on virtual nodes established on adjacent projection points on the direct connection line, and multiple co-located connected edges are obtained as virtual road segments based on virtual nodes established on the same projection point on the direct connection line. Based on all virtual road segments and the cost function of the corresponding virtual road segments, the bidirectional Dijkstra algorithm is used to calculate the route selection result of the transmission line project. Based on all virtual road segments and the corresponding cost functions for each virtual road segment, including: For any virtual road segment, calculate the total road segment cost, including the distance between one virtual node and another, and the cost coefficient *pl* for traversing terrain and obstacles. The cost function is calculated by integrating and summing the product of the distance and the cost coefficient. in, and For two adjacent virtual nodes, s∈[ → [From virtual node] arrive A segment of a virtual road that traverses various types of terrain and obstacles. Virtual road segment → The spatial distance of the segment s, The cost coefficient is determined by three types of characteristic factors: the distance between the area s spans and the road network, the topographic features, and the types of obstacles. in, In the formula, Let h be the penalty weight for the h-th land use type, and m be the total number of land use types.

2. The method for selecting the route of a transmission line project based on a road network projection algorithm according to claim 1, characterized in that, The process involves establishing a direct connection from the source point to the target point, creating an effective spatial region for power transmission line engineering route selection based on this direct connection, and then drawing equidistant projection lines on the direct connection within the effective spatial region to achieve road network projection and virtual node modeling. This includes: Establish a straight line from the source point to the target point, determine the maximum acceptable spatial range of the line selection, generate a rectangular buffer range on both sides of the straight line with a preset parameter size, and use the four corner points of the rectangle to represent the effective spatial area allowed by the line selection result. Insert n equally spaced road projection points, including the source point and the target point, on the straight line; For each road projection point, a projection line perpendicular to the straight line is drawn. Any projection line has multiple intersection points with the road network within the effective space area. Each intersection point is a virtual node. If two virtual nodes correspond to the same road projection point, the two virtual nodes are co-located. If two virtual nodes belong to two adjacent road projection points, the two virtual nodes are adjacent.

3. The method for selecting the route of a transmission line project based on a road network projection algorithm according to claim 2, characterized in that, The virtual nodes established on adjacent projection points on the direct connection line generate multiple adjacent connected edges that serve as virtual road segments, and the virtual nodes established on the same projection point on the direct connection line generate multiple co-located connected edges that serve as virtual road segments: Based on the order of road projection points, adjacent connected edges between virtual nodes under two adjacent road projection points and co-located connected edges between virtual nodes under the same road projection point are established, and each adjacent connected edge and co-located connected edge is used as a virtual road segment. The total number of virtual road segments is: in, There exists a relationship between the projection line drawn on n equidistant road projection points on a straight line within the effective spatial area and the road network. The total number of virtual road segments when there are virtual nodes. The dot symbol · indicates that the number of virtual nodes varies depending on the order of the order. This is the upper limit of the adjacent connected edges between virtual nodes established based on the order relationship between road projection point i and its adjacent road projection point i+1 within the effective spatial area. A virtual node is established at road projection point i within the effective spatial area.

4. A transmission line engineering route selection system based on road network projection algorithm, characterized in that, include: The road network projection and virtual node construction module establishes a direct connection from the source point to the target point, dynamically establishes an effective spatial area for power transmission line engineering route selection based on the direct connection, and then performs equidistant projection lines on the direct connection within the effective spatial area to realize road network projection and virtual node modeling. The connected edge acquisition module obtains multiple adjacent connected edges as virtual road segments based on virtual nodes established on adjacent projection points on the straight line, and obtains multiple co-located connected edges as virtual road segments based on virtual nodes established on the same projection points on the straight line. The route selection result calculation module, based on all virtual road segments and the cost function of the corresponding virtual road segments, uses the bidirectional Dijkstra algorithm to calculate the route selection result of the transmission line project; Based on all virtual road segments and the corresponding cost functions for each virtual road segment, including: For any virtual road segment, calculate the total road segment cost, including the distance between one virtual node and another, and the cost coefficient *pl* for traversing terrain and obstacles. The cost function is calculated by integrating and summing the product of the distance and the cost coefficient. in, and For two adjacent virtual nodes, s∈[ → [From virtual node] arrive A segment of a virtual road that traverses various types of terrain and obstacles. Virtual road segment → The spatial distance of the segment s, The cost coefficient is determined by three types of characteristic factors: the distance between the area s spans and the road network, the topographic features, and the types of obstacles. in, In the formula, Let h be the penalty weight for the h-th land use type, and m be the total number of land use types.

5. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, it implements the transmission line engineering route selection method based on the road network projection algorithm as described in any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, it implements the transmission line engineering route selection method based on the road network projection algorithm as described in any one of claims 1-3.

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