A method for handling conflicts between roads and buildings in a digital map

Abstract

The present invention belongs to the technical field of digital map processing, and particularly relates to a method for handling conflicts between roads and buildings in a digital map. The present invention first classifies building groups, including Class I, Class II, Class III, and Class IV building groups. Then, in the case of conflicts between buildings and roads in a building group, a force analysis is performed on the conflicting buildings, and the buildings are moved based on the results of the force analysis. If it is a Class III / Class IV building group, a scaling operation is also required. During the processing, the building group is used as the displacement unit for processing, effectively maintaining the spatial distribution pattern of the buildings and taking into account spatial constraints to handle spatial conflicts. It can not only reasonably displace the buildings, but also perform scaling processing on the buildings, maintaining the spatial characteristics such as the size, direction, and shape of the building group, effectively handling the spatial conflicts existing between roads and buildings, and improving the quality of digital map product updates.

Description

Technical Field

[0001] The present invention belongs to the technical field of digital map processing, and particularly relates to a method for handling conflicts between roads and buildings in a digital map. Background Art

[0002] When using large-scale data to update small-scale data, spatial conflicts often occur between the updated roads and buildings, such as mutual overlapping and too close distance. Shifting is one of the effective methods to solve spatial conflicts. Shifting mainly solves the problems of which direction to move and how much to move. A complete and effective shifting algorithm can automatically solve existing spatial conflicts, without generating new secondary conflicts, and maintaining the spatial relationship and distribution pattern between elements.

[0003] Currently, many experts and scholars have studied the problem of handling spatial conflicts between roads and buildings, mainly divided into geometric calculation methods and optimization methods. The former includes methods based on field theory, multi-level shifting methods, constrained Delaunay triangulation methods, etc. The latter mainly introduces optimization techniques to solve the shifting problem through multiple iterations, such as genetic algorithms, simulated annealing algorithms, Snake algorithms, etc. The current shifting algorithms can handle the spatial conflict problem between roads and buildings to a certain extent, but there are still deficiencies in maintaining the spatial distribution pattern of building groups. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for handling conflicts between roads and buildings in a digital map, so as to solve the problem that the existing conflict problem handling methods cannot accurately maintain the spatial distribution pattern of building groups.

[0005] To solve the above technical problems, the present invention provides a method for handling conflicts between roads and buildings in a digital map, including the following steps:

[0006] 1) Obtain a digital map, construct a road network mesh, and divide multiple building groups; classify the building groups according to the relationship between the roads and the building groups, and the classification includes Class Ⅳ building groups, and the Class Ⅳ building groups are building groups completely surrounded by roads;

[0007] 2) For a Class Ⅳ building group, determine whether each building in the building group conflicts with the road surrounding the building group. If there is a conflict, the following method is used to shift each building in the Class Ⅳ building group:

[0008] 2.1) Analyze the forces on the buildings in conflict in the building group to determine the external forces on each building in conflict;

[0009]

[0010] Wherein, F x and F y represent the total external forces received by the conflicting buildings in the X and Y directions respectively; F ix and F iy respectively represent the external forces received by the conflicting buildings in the X and Y directions under the action of the i-th road, i = 1, 2,..., n represents the index number of the road conflicting with the building, and n represents the total number of roads conflicting with the building; and F ix and F iy are respectively the X and Y direction components of the external force F i received by the conflicting building under the action of the i-th road, and F i is:

[0011]

[0012] Wherein, v i represents the maximum distance vector of the conflict area between the i-th road and the building, r represents the minimum interval between elements on the map, and M represents the map scale;

[0013] 2.2) Determine the distance and direction that each building needs to move according to the external forces received by each conflicting building; select the building with the largest distance to be moved as the first building; move the first building according to the distance and direction that the first building needs to move, and then perform linkage movement processing on other buildings in the building group; after all buildings are moved, perform scaling processing on all buildings in the building group;

[0014] 2.3) After the scaling processing, re-judge whether each building in the building group conflicts with the road surrounding the building group: if there is a conflict, repeat steps 2.1) to 2.2) until there is no conflict; if there is no conflict, complete the displacement processing of this type of building group.

[0015] The beneficial effects are as follows: Regarding the surrounding relationship between buildings and roads, part of the building groups are classified as the fourth-category building groups. In the case of conflicts between the fourth-category building groups and roads, first, conduct a force analysis on the buildings in conflict to determine the magnitude and direction of movement. Then, find the building with the largest distance to be moved among them and use it as the first building for movement processing. Next, perform linkage movement processing on the subsequent other buildings, and then perform scaling processing on the buildings. Repeat the process described above to complete the displacement processing of this type of building group. The present invention takes the fourth-category building group as the displacement unit for processing, effectively ensuring the spatial distribution pattern of the buildings, improving the consistency of spatial data. Moreover, during the displacement processing, including two steps of movement and scaling, it ensures the spatial characteristics such as the size, direction, and shape of the building group, maintains the characteristics such as the connectivity and density of the block, effectively solves the conflicts between the road and the fourth-category buildings, improves the automation degree of spatial conflict processing, has high processing efficiency, and improves the quality of digital map product updates.

[0016] Further, in step 1), the classification further includes the third-category building group, and the third-category building group is a building group adjacent to roads on three sides. For a third-category building group, determine whether there are conflicts between the buildings in the building group and the roads surrounding the building group. If there are conflicts, complete the roads. After completion, use the same displacement processing method as the fourth-category building group to perform displacement processing on the buildings in the third-category building group.

[0017] The beneficial effects are as follows: Regarding the surrounding relationship between buildings and roads, part of the building groups are classified as the third-category building groups. In the case of conflicts between the third-category building groups and roads, use the same displacement processing method as the fourth-category building group for displacement processing. Similarly, it can effectively solve the conflicts between the road and the third-category buildings, has high processing efficiency, and improves the quality of digital map product updates.

[0018] Further, in step 1), the classification further includes Class I building groups and / or Class II building groups. The Class I building group is a building group adjacent to a road on only one side, and the Class II building group is a building group adjacent to roads on both sides. For a Class I building group / Class II building group, it is determined whether there is a conflict between each building in the building group and the roads surrounding the building group. If there is a conflict, the following method is used to displace the buildings in the building group: ① Use the same method as in step 2.1) to analyze the forces on the buildings in conflict in the building group to determine the external forces on each building in conflict; ② Based on the external forces on each building in conflict, determine the distance and direction each building needs to move. Select the building with the largest distance to move as the first building. According to the distance and direction the first building needs to be displaced, the first building is displaced, and then the other buildings in the building group are displaced in a linked manner; ③ After displacement, it is re-determined whether there is a conflict between each building in the building group and the roads surrounding the building group. If there is a conflict, steps ① to ② are repeated until there is no conflict. If there is no conflict, the displacement process for this type of building group is completed.

[0019] The beneficial effects are as follows: Regarding the surrounding relationship between buildings and roads, some building groups are classified as Class I building groups, and some building groups are classified as Class II building groups. For the situation where a Class I building group / Class II building group conflicts with a road, a different processing method from that of Class III and Class IV building groups is adopted, which can meet the displacement processing methods for different types of building groups. In the face of the situation where a Class I building group / Class II building group conflicts with a road, first, the forces on the conflicting buildings are analyzed to determine the magnitude and direction of movement, then the building with the largest distance to move is found and used as the first building for displacement processing, and then the subsequent other buildings are displaced in a linked manner. The above-introduced process is repeated to complete the displacement process for this type of building group. This processing method takes the Class I building group / Class II building group as the displacement unit for processing, effectively ensuring the spatial distribution pattern of the buildings and improving the consistency of spatial data.

[0020] Further, when displacing the other buildings in the building group in a linked manner in step 2.2), the center-of-gravity coordinates of the next building to be displaced after displacement are:

[0021]

[0022] Wherein, (x2, y2) represents the coordinates of the center of gravity of the next building to be moved after movement, (x1, y1) represents the coordinates of the center of gravity of the previous moved building after movement, d represents the distance between the centers of gravity of the two buildings to be moved in linkage before movement, θ represents the azimuth angle between the centers of gravity of the two buildings to be moved in linkage before movement, and λ represents the distance scaling ratio for scaling processing.

[0023] Further, when performing the scaling processing in step 2.2), the center of gravity of each building remains unchanged, and the vertex coordinates of the building after scaling processing are:

[0024]

[0025] Wherein, (x2, y2) represents the coordinates of a certain vertex before the scaling processing of the building, (x a ', y a ') represents the coordinates of the vertex (x2, y2) after the scaling processing, and (x, y) represents the coordinates of the center of gravity of the building.

[0026] Its beneficial effect is that: the method of equal-proportion reduction based on vectors is used to scale the building polygon, ensuring the movement space and the characteristics of each building in the building group.

[0027] Further, the distance scaling ratio λ is:

[0028]

[0029] Wherein, Area after represents the area of the road mesh where the building group is located after symbolization, Area before represents the area of the road mesh where the building group is located, and ratio represents the scaling area ratio of the building.

[0030] Its beneficial effect is that: when performing the scaling processing, the square of the distance scaling ratio is the area ratio, thus maintaining the area ratio of the building.

[0031] Further, for the type-IV building group and the type-III building group, it is also necessary to use the minimum spanning tree method to describe the spatial neighbor relationship of each building belonging to a building group, so as to construct the minimum spanning tree of each building group; correspondingly, in step 2.2), the other buildings in the building group are processed for linkage movement according to the spatial neighbor relationship of the buildings determined by the minimum spanning tree.

[0032] Furthermore, for the building groups of type Ⅳ and type Ⅲ, the minimum spanning tree method is also required to describe the spatial adjacency relationships of the individual buildings belonging to a building group, so as to construct the minimum spanning tree of each building group; correspondingly, in step ②, the other buildings in the building group are processed for linkage movement based on the spatial adjacency relationships of the buildings determined by the minimum spanning tree.

[0033] The beneficial effect is that the minimum spanning tree method is used to describe the spatial adjacency relationships of the individual buildings, and the method is simple and effective.

[0034] Furthermore, in the process of constructing the minimum spanning tree, the minimum spanning tree needs to be pruned according to the following method: if the edge of the minimum spanning tree intersects with a road, then delete the edge; if the length of the edge of the minimum spanning tree exceeds the set length threshold, then delete the edge.

[0035] The beneficial effect is that pruning the minimum spanning tree realizes the further optimization of the minimum spanning tree to keep the spatial distribution pattern of the buildings from being damaged.

[0036] Furthermore, the Prim algorithm is used to construct the minimum spanning tree. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flowchart of the method for handling conflicts between roads and buildings in the digital map of the present invention;

[0038] FIG. 2(a) is a schematic diagram of the building group of type Ⅰ of the present invention;

[0039] FIG. 2(b) is a schematic diagram of the building group of type Ⅱ of the present invention;

[0040] FIG. 2(c) is a schematic diagram of the building group of type Ⅲ of the present invention;

[0041] FIG. 2(d) is a schematic diagram of the building group of type Ⅳ of the present invention;

[0042] Figure 3 is a minimum spanning tree diagram of the building group;

[0043] Figure 4 is a force analysis diagram of the building;

[0044] Figure 5 is a schematic diagram of the scaling process of the building;

[0045] FIG. 6(a) is a comparison diagram before and after displacement in Example 1;

[0046] FIG. 6(b) is a comparison diagram before and after displacement in Example 2;

[0047] Figure 7 is a displacement processing result diagram of the building-intensive area. DETAILED DESCRIPTION

[0048] The present invention classifies building groups according to the relationship between roads and buildings, that is, the surrounding situation of roads on buildings. When conflicts occur between roads and buildings, different displacement processing methods are adopted for buildings belonging to different categories of building groups. For each type of building group, it is necessary to conduct a force analysis on the buildings therein, and determine the distance and direction to be moved based on the force analysis results. For buildings in the first and second category building groups, they can be directly moved in the direction without roads. For buildings in the third and fourth category building groups, the building that needs to be moved the maximum distance is first found, and it is used as the first building to be moved. The remaining buildings are linked to move based on this. After the movement process, each building needs to be scaled, so as to effectively deal with the spatial conflict between roads and buildings and improve the quality of digital map product updates.

[0049] A method for handling conflicts between roads and buildings in a digital map of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0050] Embodiment of the method for handling conflicts between roads and buildings in digital maps:

[0051] An embodiment of a method for shifting roads and buildings in a map facing spatial constraints according to the present invention has the following process: Figure 1 As shown, the process is as follows:

[0052] Step 1: Obtain a digital map, construct a road network, and divide multiple building groups; classify the building groups according to the surrounding conditions of the roads. This method divides the building groups into the following four categories: Figures 2(a) to 2(d) shown.

[0053] ① Category I, as shown in Figure 2(a), only one side of the building group is adjacent to the road, and the road does not surround the building group. If a conflict occurs, there is a lot of room for displacement, and it only needs to move to the direction without the road;

[0054] ② Category II, as shown in Figure 2(b), the buildings are adjacent to roads on both sides, and the roads semi-enclose the buildings. If a conflict occurs, the space available for displacement is relatively large;

[0055] ③ Category III, as shown in Figure 2(c), the building cluster is adjacent to roads on three sides, and the roads surround the building cluster to a large extent. If a conflict occurs, the building cluster can move to the side without roads and the inside of the building cluster;

[0056] ④ Class IV, as shown in Fig. 2(d), the four sides of the building group are adjacent to roads, and the roads form a complete enclosure around the building group. If a conflict occurs, it can only be shifted inward to the building.

[0057] In this embodiment, the building is divided into four sides as a whole. However, in actual situations, the building group is not a regular rectangle. Therefore, in the present invention, the building group is approximated as a rectangle for subsequent processing. As can be seen from the above classification, for Class I and Class II situations, the degree of enclosure of the building group by the roads is relatively small. If a conflict occurs, it only needs to be moved in the direction without roads. For Class III and Class IV situations, the degree of enclosure of the building group by the roads is relatively large. If a conflict occurs, it needs to be moved inward to the building group. Considering that the building groups will be squeezed against each other, a shrinking process is also required. Therefore, in the face of Class I and Class II situations, the "shift" in the present invention only includes "movement", while in Class III and Class IV situations, the "shift" in the present invention includes "movement" and "scaling". The purpose of classifying the relationship between the roads and the building group is mainly to classify the building group and adopt different shifting methods for different classifications for separate processing.

[0058] Step 2: Construct a minimum spanning tree to describe the spatial proximity relationship of each building belonging to the same building group. For Class I and Class II building groups, construct a minimum spanning tree, and during the construction process, "pruning" processing needs to be carried out according to the set distance threshold. For Class III building groups, use roads to complete and transform them into Class IV building groups for processing. For Class IV building groups, directly construct the minimum spanning tree of the building group. After constructing the minimum spanning tree of each building group, the length characteristics and angle characteristics of the minimum spanning tree need to be recorded.

[0059] The method of using the minimum spanning tree (MST) is adopted to describe the spatial proximity relationship of the buildings. Assume that the building group G = (V, E), the vertex V represents the centroid of each building in the building group, and the edge E represents the connecting line segment of each centroid. For any edge (u, v) in E, define the weight dis(u, v) as the distance between points u and v. If there exists a subset T of E and it is an acyclic graph such that dis(T) is the minimum, then T is the minimum spanning tree of G. In this embodiment, the Prim algorithm is adopted to construct the minimum spanning tree, and the constructed minimum spanning tree is as Figure 3 shown.

[0060] For the first - type and second - type building groups, first construct their minimum spanning tree, and then determine whether the edges of the minimum spanning tree intersect with the road. If they intersect, delete the edge. At the same time, determine whether the distance of the edge exceeds a certain set distance threshold. If it exceeds the set distance threshold, delete the edge. Through this "pruning" method, optimize the building group, and the corresponding minimum spanning tree is also constructed for the optimized building group. Finally, take the obtained building group as the shifting unit for processing to ensure that the spatial distribution pattern of the buildings is not damaged. For the third - type and fourth - type building groups, they are usually separated by roads and distributed in the form of blocks. At this time, the road mesh can be used as a constraint, and the buildings within the road mesh are regarded as a whole, and then the minimum spanning tree is constructed. Moreover, for the third - type building group, it needs to be complemented with roads so that the third - type building group is transformed into the fourth - type building group for processing.

[0061] To maintain the spatial distribution characteristics of the buildings before and after displacement, based on the minimum spanning tree, extract the length characteristics and angle characteristics of the building group. The length is the distance between the centroids of adjacent buildings, and the angle is the azimuth angle between the centroids. In this embodiment, it is represented by the horizontal angle between the line segment connecting the centroids and the positive direction of the X - axis.

[0062] Step three, when the road conflicts with one or several buildings in the building group, perform displacement processing on the building group. Different types of building groups have different displacement processing methods.

[0063] (1) For the buildings in the first two types of building groups that conflict with the road, first, it is necessary to conduct a force analysis on them to determine the magnitude and direction of movement, and then perform the movement processing to achieve the displacement of this type of building group. The specific processing flow is as follows:

[0064] 1. Calculate the external forces acting on the buildings in the building group that conflict. Based on the external forces acting on each conflicting building, determine the distance and direction that each building needs to move.

[0065] When performing displacement processing on a building, first calculate the magnitude of the external force that promotes the movement, that is, the external force acting on the building determines its direction and magnitude of movement. When calculating, it can be represented by the minimum distance from the road to the building. When there is a spatial conflict, the magnitude of the external force mainly depends on the overlapping amount between the road and the building and the minimum spacing requirement between the elements.

[0066] As Figure 4 shown, assume that the maximum distance vector between a certain road (i represents the number of roads, i = 1 in the following formula) and the conflict area of the building is v i , then the external force calculation formula is:

[0067]

[0068] Wherein, r represents the minimum interval between elements on the map (generally taking 0.2 mm); M represents the map scale, and F i represents the external force vector of the road on the building group.

[0069] When a building is subjected to external forces from multiple roads, it is necessary to sum the external force vectors, calculate the magnitude and direction of the external force, and then move the building. Assume that the building is subjected to the forces of n roads, which are respectively denoted as F i (0 ≤ i ≤ n), and decompose them on the X and Y axes respectively to obtain F ix and F iy , and then perform vector summation to obtain the magnitudes of the external forces received by the building in the X and Y directions, F x and F y , which are denoted as:

[0070]

[0071] The resultant magnitude and direction of the external forces F x and F y received are the magnitude and direction by which the building needs to be moved.

[0072] 2. Select the building with the largest distance to be moved as the first building to be processed for movement, and move the first building according to the distance and direction it needs to be moved.

[0073] 3. According to the relationship between buildings determined by the minimum spanning tree, traverse the minimum spanning tree and perform linkage movement processing on the remaining buildings in the building group. The distance and direction of movement are the same as those of the first building.

[0074] 4. After the movement processing, determine whether there is still a conflict between the buildings in the building group and the road: if not, complete the displacement processing of the building group; if still present, re-execute steps 1 to 3 until there is no conflict between the buildings in the building group and the road.

[0075] (2) For the buildings in the latter two types of building groups that conflict with the road, first, it is also necessary to perform a force analysis on them, and use the area constraint condition to determine the area scaling ratio and distance scaling ratio, so as to determine the magnitude and direction of the building movement, then perform the movement processing, and then scale each building while keeping the center of gravity of each building unchanged, thereby completing the displacement of this type of building group. The specific processing flow is as follows:

[0076] 1. For a building group that needs to be scaled in area, in order to keep the areas of the buildings similar before and after displacement, the present invention mainly performs scaling processing with area as the constraint. Assume that the area of a certain road mesh is Area before , and the area of the symbolized road mesh is Area after . Then, the area ratio of the buildings within this road mesh before and after displacement processing should be:

[0077]

[0078] The distance scaling ratio is:

[0079]

[0080] The scaling ratio in formula (4) is the basis for subsequent scaling of the buildings in this building group.

[0081] 2. Calculate the external forces acting on the buildings in conflict in the building group. The calculation method is the same as that when the building group is the first two types of building groups, and the specific formulas are as shown in formulas (1) and (2). Based on the external forces acting on each building in conflict, determine the distance and direction that each building needs to move.

[0082] 3. Find the building that needs to move the maximum distance and use it as the first building for movement processing. Subsequent movement processing is carried out in a linked manner based on this.

[0083] 4. On the basis of moving the first building, perform linked movement processing on other buildings according to the association relationship between buildings determined by the minimum spanning tree, and determine the movement of the remaining buildings according to the recorded length characteristics, angle characteristics, and distance scaling ratio. Assume that buildings b1 and b2 are two adjacent buildings on the minimum spanning tree, the original distance between the centroids of the two buildings is d, the azimuth angle is θ, b1 is the building that has been moved, and its moved centroid coordinates are p1(x1, y1), and b2 is the building that needs to be moved according to b1. Then, the centroid coordinates p2(x2, y2) of b2 after movement processing are:

[0084]

[0085] 5. Traverse the minimum spanning tree and move the buildings within the road mesh to achieve the linked movement processing of other buildings with the first building.

[0086] 6. After movement, perform area transformation on the buildings. The centroid of the scaled building remains unchanged. Determine the coordinates of each vertex of the scaled building to obtain the new building.

[0087] Assume that there are m buildings within this road mesh, and the area of the i-th building is Area i1, according to the area ratio value of ratio, after the shifting process, the area of the building becomes:

[0088] Area i2 =Area i1 ×ratio (6)

[0089] As Figure 5 shown, assuming the centroid position of the building is P(x, y) and the scaling ratio is λ, according to the proportional relationship of vectors, we can obtain:

[0090]

[0091] Assume the coordinates of the original building vertex A are (x a , y a ), and the coordinates of A' after the shifting process are (x a ', y a '), then:

[0092]

[0093] 7. After completing the above operations, determine whether there is still a conflict between the buildings in the building group and the road: If not, complete the shifting process of the building group; if still exists, re - execute steps 1 - 6 until there is no conflict between the buildings in the building group and the road.

[0094] Thus, the shifting process of all building groups can be completed to obtain the final shifting result.

[0095] Next, the method will be applied to a specific example to illustrate the effectiveness of the method of the present invention.

[0096] Select the road and residential area data at a scale of 1:50,000 for experiments, which includes a total of 54 road segments, 70 buildings, and 21 road meshes. Due to symbolization, there are spatial conflicts between the roads and the buildings. Perform the shifting process on the buildings according to the method of the present invention. The comparison before and after shifting for two examples is shown in Figures 6(a) and 6(b) respectively. The black empty polygons represent the buildings before shifting, and the solid polygons represent the buildings after shifting. It can be seen that through the shifting process, the spatial conflicts between the roads and the residential areas can be effectively solved, and taking the building group as the processing unit can keep the spatial distribution pattern undamaged.

[0097] Figure 7 Shows the enlarged situation of the road mesh. It can be seen from the figure that due to the dense buildings and the relatively crowded overall space, but using the method of the present invention can not only reasonably shift the buildings, but also perform scaling processing on the buildings to ensure the shifted space, thus maintaining features such as the connectivity and density of the block.

Claims

1. A method for handling conflicts between roads and buildings in a digital map, characterized in that The steps are as follows: 1) Obtain a digital map, construct a road network mesh, and divide multiple building clusters; classify the building clusters according to the relationship between the roads and the building clusters, and the classification includes Class IV building clusters, where the Class IV building clusters are building clusters completely surrounded by roads; 2) For a Class IV building cluster, determine whether there is a conflict between each building in the building cluster and the roads surrounding the building cluster. If there is a conflict, the following method is used to displace each building in the Class IV building cluster: 2.1) Analyze the forces acting on the buildings in conflict in the building cluster to determine the external forces acting on each building in conflict; In the formula, F x and F y represent the total external forces acting on the conflicting buildings in the X and Y directions respectively; F ix and F iy respectively represent the external forces acting on the conflicting buildings in the X and Y directions under the action of the i-th road, where i = 1, 2, …, n represents the index number of the roads conflicting with the building, and n represents the total number of roads conflicting with the building; and F ix and F iy are respectively the X and Y direction components of the external force F i acting on the conflicting building under the action of the i-th road, and F i is: where v i represents the maximum distance vector of the conflict area between the i-th road and the building, r represents the minimum interval between elements on the map, and M represents the map scale; 2.2) Determine the distance and direction that each building needs to move according to the external forces acting on each building in conflict; select the building with the largest distance to be moved as the first building; According to the distance and direction that the first building needs to move, move the first building, and then perform linkage movement processing on other buildings in the building group; after all buildings have been moved, perform scaling processing on all buildings in the building group with the center of gravity unchanged, and the vertex coordinates (x a ', y a ) after scaling are as follows: (x2, y2) is the coordinate of a certain vertex of the building before scaling, (x, y) is the centroid coordinate of the building, and λ is the distance scaling ratio for scaling processing; 2.3) After scaling processing, re-determine whether there is a conflict between each building in the building cluster and the roads surrounding the building cluster: if there is a conflict, repeat steps 2.1) - 2.2) until there is no conflict; If there is no conflict, the displacement processing of this type of building cluster is completed.

2. The method for handling conflicts between roads and buildings in a digital map according to claim 1, wherein In step 1), the classification further includes Class III building clusters, where the Class III building clusters are building clusters adjacent to roads on three sides; for a Class III building cluster, determine whether there is a conflict between each building in the building cluster and the roads surrounding the building cluster. If there is a conflict, complete the roads, and after completion, use the same displacement processing method as for Class IV building clusters to displace each building in the Class III building cluster.

3. The method for handling the conflict between roads and buildings in a digital map according to claim 1, wherein In step 1), the classification further includes Class I building clusters and / or Class II building clusters, where the Class I building clusters are building clusters adjacent to roads on only one side, and the Class II building clusters are building clusters adjacent to roads on two sides; For a Class I building cluster / Class II building cluster, determine whether there is a conflict between each building in the building cluster and the roads surrounding the building cluster. If there is a conflict, the following method is used to displace each building in the building cluster: ① Use the same method as in step 2.1) to analyze the forces acting on the buildings in conflict in the building cluster to determine the external forces acting on each building in conflict; ② Determine the distance and direction that each building needs to move according to the external forces acting on each building in conflict; select the building with the largest distance to be moved as the first building; Move the first building according to the distance and direction that the first building needs to be displaced, and then perform a linkage movement process on the other buildings in the building cluster; ③ After moving, re-determine whether there is a conflict between each building in the building cluster and the roads surrounding the building cluster. If there is a conflict, repeat steps ① - ② until there is no conflict; If there is no conflict, the displacement processing of this type of building cluster is completed.

4. The method for handling conflicts between roads and buildings in a digital map according to claim 1 or 2, characterized in that When performing linkage movement processing on other buildings in the building group in step 2.2), the center-of-gravity coordinates of the next building to be moved after movement are as follows: In the formula, (x2, y2) represents the center-of-gravity coordinates of the next building to be moved after movement, (x1, y1) represents the center-of-gravity coordinates of the previous moved building after movement, d represents the distance between the centers of gravity of the two buildings undergoing linkage movement before movement, and θ represents the azimuth angle between the centers of gravity of the two buildings undergoing linkage movement before movement.

5. The method for handling conflicts between roads and buildings in a digital map according to claim 1, characterized in that, The distance scaling ratio λ is: where Area after represents the area of the road mesh where the building group is located after symbolization, and Area before represents the area of the road mesh where the building group is located, and ratio represents the scaling area ratio of the building.

6. The method for handling the conflict between roads and buildings in a digital map according to claim 1, wherein, For the type-IV building group and the type-III building group, it is also necessary to use the minimum spanning tree method to describe the spatial neighbor relationships of the buildings belonging to a building group, so as to construct the minimum spanning tree of each building group; Accordingly, in step 2.2), linkage movement processing is performed on other buildings in the building group according to the spatial neighbor relationships of the buildings determined by the minimum spanning tree.

7. The method for handling conflicts between roads and buildings in a digital map according to claim 3, characterized in that, For the type-IV building group and the type-III building group, it is also necessary to use the minimum spanning tree method to describe the spatial neighbor relationships of the buildings belonging to a building group, so as to construct the minimum spanning tree of each building group; accordingly, in step ②, linkage movement processing is performed on other buildings in the building group according to the spatial neighbor relationships of the buildings determined by the minimum spanning tree.

8. The method for handling conflicts between roads and buildings in a digital map according to claim 7, characterized in that, During the process of constructing the minimum spanning tree, the minimum spanning tree needs to be pruned according to the following method: if the edge of the minimum spanning tree intersects with the road, then delete the edge; if the length of the edge of the minimum spanning tree exceeds the set length threshold, then delete the edge.

9. The method for handling the conflict between roads and buildings in a digital map according to claim 6, characterized in that The minimum spanning tree is constructed using the Prim algorithm.

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