Methods for determining the overlapping relationship of planar features in a plan view

Abstract

This invention provides a method for determining the overlapping relationship of planar elements in a planar drawing. It utilizes the connection relationship between the central contact point of three contacting planar elements and three straight line segments located on three contact lines of the three planar elements. Based on the rule that a planar element defined by two straight line segments on the same line overlaps the other two planar elements, the overlapping relationship between the three contacting planar elements is determined. Due to potential errors, theoretically, two straight line segments on the same line may have a slope difference. Within the allowable error range, the overlapping relationship between planar elements can be determined by calculating the slope differences between each pair of the three straight line segments: the planar element defined by the two straight line segments with the smallest slope difference overlaps the other two planar elements. This invention simplifies the method for determining the overlapping relationship of planar elements, significantly improves efficiency and accuracy, and can also be used for batch automatic identification by computer.

Description

Technical Field

[0001] This invention belongs to the field of map making technology, and specifically relates to a method for determining the overlapping relationship of planar elements in a planar map. Background Technology

[0002] The overlay relationship of areal features in a planar map (such as a geological map or other maps, construction drawings, and design drawings that need to reflect the relationships between strata, whether they are of different ages or hierarchical relationships) is reflected through the contact relationships between areal features. Newer or overlying areal features overlay older or underlying areal features; by determining the overlay relationship, the age or hierarchical relationship of areal features can be accurately determined in the planar map. In short, the age or hierarchical relationship of areal features is one of the key pieces of information for the creation and interpretation of planar maps, and it is also an important basis for reflecting the inherent logic between areal features in a planar map. Therefore, whether the overlay relationship of areal features in a planar map is correct is one of the important indicators for evaluating the quality of a planar map.

[0003] Currently, the overlapping relationships of planar features in a plan view are determined and drawn based on the cartographer's experience. However, the overlapping relationships in a plan view are mainly judged by the annotations on the planar features. The overlapping relationships reflected by the curve contact relationships around the planar features are often ignored, resulting in many errors or conflicts in the overlapping relationships of planar features in the plan view. This not only affects the quality of the plan view, but also fails to accurately reflect the new and old relationships or the vertical relationships between planar features in the plan view. Summary of the Invention

[0004] The purpose of this invention is to solve the problems caused by insufficient experience or complex overlapping relationships of planar elements in the process of map making. It can help cartographers quickly identify errors or conflicts in the overlapping relationships of planar elements in the map, so as to make targeted modifications, thereby improving the quality of map making and reducing the workload.

[0005] To achieve the above-mentioned objectives, the present invention employs the following technical solution:

[0006] A method for determining the overlapping relationship of planar elements in a planar drawing utilizes the connection relationship between the central contact point of three mutually contacting planar elements and the three straight line segments between the three contact points on the three contact lines of the three planar elements. Based on the rule that a planar element overlaps two other planar elements as defined by two straight line segments on the same straight line, the overlapping relationship between the three mutually contacting planar elements is determined.

[0007] The above technical solution embodies the basic principle of this invention. The basic principle of this invention is as follows: In a planar drawing that needs to reflect overburden relationships, regardless of the complexity of the overburden relationships between planar elements, the newest (or overlying) planar element can be determined one by one by examining three contacting planar elements. There must be a central contact point (located at the contact point of the three planar elements) and three contact lines (boundaries between any two geological bodies connected to the central contact point). By determining a node closest to the central contact point on each of the three contact lines, three straight line segments are formed between the central contact point and the three nodes. Connecting the three straight line segments with the central contact point as the connecting point, when there is an overburden relationship between the three planar elements, the connection relationship between the three straight line segments is that only two straight line segments lie on the same straight line. The planar element defined by this set of straight line segments lying on the same straight line is necessarily the newest (or overlying) planar element. In short, the overlapping relationship of planar features is reflected in the area near the central contact point of three planar features, where the planar feature defined by two line segments on the same straight line overlaps the other two planar features.

[0008] In principle, if no two of the aforementioned three straight line segments lie on the same straight line, it means that there is no overlapping relationship between the three contacting planar elements. However, it is worth noting that in actual operation, due to errors, two straight line segments that are theoretically on the same straight line may not be on the same straight line because their slopes are not completely equal. This invention allows for a certain degree of error. Generally speaking, if the angle difference between two straight line segments is within ±1 degree, these two straight line segments can be considered to meet the requirement of being on the same straight line, thereby determining the corresponding overlapping relationship.

[0009] Based on the above technical solution, the present invention may employ the following additional technical means to better achieve the purpose of the present invention:

[0010] The method for determining the overlapping relationship of planar features in a plan view specifically includes the following steps:

[0011] S01: Select a polygon feature vector file or layer with correct topological relationships;

[0012] S02: Define three planar features as planar feature A, planar feature B, and planar feature C. The contact point of planar feature A, planar feature B, and planar feature C is defined as the central contact node abc. Define the three nodes near the central contact point abc that are closest to the central contact node abc on the contact line between any two adjacent planar features as nodes ab, ac, and bc. Then the straight line segments between nodes ab, ac, bc and the central contact point abc are straight line segments ab, ac, and bc, respectively.

[0013] S03: Determine the overlay relationship of planar elements based on the connection relationship between line segments ab, ac, and bc. That is, the planar elements defined by this set of line segments on the same line must be the newest or the uppermost planar elements.

[0014] Furthermore, when performing step S03, the determination rule is: the planar features defined by the two line segments with the smallest differences in slope between line segment ab and line segment ac, slope between line segment ab and line segment bc, and slope between line segment bc and line segment ac overlap the other two planar features.

[0015] Furthermore, simplifying step S03, it is only necessary to calculate the relationship between the four nodes—the center contact node abc, node ab, node ac, and node bc—of the three planar features to determine the overlapping relationship between planar feature A, planar feature B, and planar feature C. The calculation formula is as follows:

[0016] The slope of line segment ab = (y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )

[0017] The slope of line segment bc = (y 节点bc -y 节点abc )÷(x 节点bc -x 节点abc )

[0018] The slope of line segment ac = (y 节点ac -y 节点abc )÷(x 节点ac -x 节点abc )

[0019] The formula for the difference in slope between two straight line segments is:

[0020] The difference in slope between line segments ab and bc = |(y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )-(y 节点bc -y节点abc )÷(x 节点bc -x 节点abc )|

[0021] The difference in slope between line segment ab and line segment ac = |(y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )-(y 节点ac -y 节点abc )÷(x 节点ac -x 节点abc )|

[0022] The difference in slope between line segment bc and line segment ac = |(y 节点bc -y 节点abc )÷(x 节点bc -x 节点abc )-(y 节点ac -y 节点abc )÷(x 节点ac -x 节点abc )|

[0023] Furthermore, the plan view is a geological map.

[0024] Compared with existing methods for determining the overlapping relationship of planar features, the main advantages of this invention are as follows:

[0025] Regarding the overlapping relationship of planar features, this invention changes the original method of judging by the smoothness of the planar feature boundary to judging by the relationship between the central contact node and the three nodes closest to the central contact node (e.g., the slope difference between straight line segments). In short, for the identification of planar feature overlapping relationships, this invention transforms the previously complex graphic relationship identification into identification through calculation of four coordinate points. This invention not only simplifies the judgment method but also significantly improves efficiency and accuracy, and can also be used for batch automatic identification by computer. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the contact relationship between the three planar elements in Embodiment 1 of the present invention; Detailed Implementation

[0027] To facilitate a thorough understanding of the technical solution of this invention by those skilled in the art, an embodiment of this invention is described below with reference to the accompanying drawings and tables, using the determination of geological body cover relationships in geological maps as an example.

[0028] like Figure 1As shown, a method for determining the overlay relationship of planar elements in a planar diagram identifies the connection relationship between the central contact node of three contacting geological bodies and the three straight line segments located on the three contact lines closest to the central contact node. Based on the rule that a geological body overlays two other geological bodies defined by two straight line segments on the same straight line (theoretically, due to errors, there may be a certain slope difference between two straight line segments on the same straight line; within the allowable error range, this can be determined by calculating the slope difference between each pair of the three straight line segments), the overlay relationship between the three contacting geological bodies is determined, including the following specific steps:

[0029] S01: Select the correct geological body vector file or layer (e.g., geological body area file);

[0030] S02: Let three contacting geological bodies be geological body A, geological body B, and geological body C. Let the contact point of geological bodies A, B, and C be the central contact node abc. Let the three nearest nodes of the central contact node abc, located on the contact line between any two adjacent geological bodies, be nodes ab, ac, and bc. Then the straight line segments between nodes ab, ac, bc and the central contact node abc are respectively straight line segment ab (the common straight line segment of geological body A and geological body B), straight line segment ac (the common straight line segment of geological body A and geological body C), and straight line segment bc (the common straight line segment of geological body B and geological body C).

[0031] S03: Determine the overlay relationship of geological bodies based on the connection relationship between straight line segments ab, ac, and bc. That is, the geological body defined by this set of straight line segments located on the same straight line overlays two other geological bodies.

[0032] In this embodiment, the connection relationship of the relevant straight segments and the overburden relationship at the contact points of the three geological bodies A, B, and C are determined as shown in Table 1.

[0033] Table 1. Relationship between relevant straight segments at the contact points of three geological bodies and determination of the overburden relationship between geological bodies.

[0034]

[0035]

[0036] pass Figure 1 Based on Table 1 and the judgment rules of this invention, it can be determined that geological body A covers geological body B and geological body C.

[0037] It should also be noted that, in the process of implementing the present invention according to the technical solution described in Example 1, S03 can be further simplified: it is only necessary to calculate the relationship between the four nodes abc, the central contact node of the three geological bodies, and the nodes ab, ac, and bc, which are the closest to the central contact node abc, to determine the overburden relationship between geological bodies A, B, and C. The calculation formula is as follows:

[0038] The slope of line segment ab = (y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )

[0039] The slope of line segment bc = (y 节点bc -y 节点abc )÷(x 节点bc -x 节点abc )

[0040] The slope of line segment ac = (y 节点ac -y 节点abc )÷(x 节点ac -x 节点abc )

[0041] The formula for the difference in slope (absolute value) between two arc segments is:

[0042] The difference in slope between line segments ab and bc = |(y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )-(y 节点bc -y 节点abc )÷(x 节点bc -x 节点abc )|

[0043] The difference in slope between line segment ab and line segment ac = |(y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )-(y 节点ac -y 节点abc )÷(x 节点ac -x 节点abc )|

[0044] The difference in slope between line segment bc and line segment ac = |(y 节点bc -y 节点abc )÷(x 节点bc -x 节点abc )-(y 节点ac -y 节点abc )÷(x 节点ac -x 节点abc )|

[0045] Among the slope differences mentioned above, the planar features defined by the two straight line segments with the smallest slope difference overlap the other two planar features. For example, if the planar feature defined by straight line segments ab and bc is geological body A, and the slope difference between straight line segments ab and bc is the smallest among the three slope differences mentioned above, it means that geological body A overlaps geological bodies B and C.

Claims

1. A method for determining the overlapping relationship of planar elements in a planar drawing, characterized in that: The overlapping relationship between the three contacting planar elements is determined by utilizing the connection relationship between the center contact point of three contact points on the three contact lines of the three planar elements and the three straight line segments between the three contact points. This is based on the rule that a planar element overlapping two other planar elements is defined by two straight line segments on the same straight line. Specifically, the following steps are included: S01: Select a polygon feature vector file or layer with correct topological relationships; S02: Define three planar features as planar feature A, planar feature B, and planar feature C. The contact point of planar feature A, planar feature B, and planar feature C is defined as the central contact node abc. Define the three nodes near the central contact point abc that are closest to the central contact node abc on the contact line between any two adjacent planar features as nodes ab, ac, and bc. Then the straight line segments between nodes ab, ac, bc and the central contact point abc are straight line segments ab, ac, and bc, respectively. S03: Determine the overlay relationship of planar elements based on the connection relationship between line segments ab, ac, and bc. That is, the planar elements defined by this set of line segments on the same line must be the newest or the uppermost planar elements.

2. The method for determining the overlapping relationship of planar elements in a planar drawing as described in claim 1, characterized in that: When performing step S03, the determination rule is: the two line segments with the smallest differences in slope between line segment ab and line segment ac, slope between line segment ab and line segment bc, and slope between line segment bc and line segment ac, define the planar features that overlap the other two planar features.

3. The method for determining the overlapping relationship of planar elements in a planar drawing as described in claim 2, characterized in that: Simplifying step S03, it is only necessary to calculate the relationship between the four nodes (abc, ab, ac, and bc) at the center contact points of the three planar features to determine the overlapping relationship between planar features A, B, and C. The calculation formula is as follows: The slope of line segment ab = (y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc ) The slope of line segment bc = (y 节点bc -y 节点abc )÷(x 节点bc -x 节点abc ) The slope of line segment ac = (y 节点ac -y 节点abc )÷(x 节点ac -x 节点abc ) The formula for the difference in slope between two straight line segments is: The difference in slope between line segments ab and bc = |(y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )-(y 节点bc -y node abc)÷(x node bc-x node abc)| The difference in slope between line segment ab and line segment ac = |(y 节点ab -y 节点abc )÷(x 节点ab -x 节点abc )-(y 节点ac -y node abc)÷(x node ac-x node abc)| The difference in slope between line segment bc and line segment ac = |(y 节点bc -y 节点abc )÷(x 节点bc -x 节点abc )-(y 节点ac -y node abc)÷(x node ac-x node abc)|.

4. The method for determining the overlapping relationship of planar elements in a planar drawing as described in any one of claims 1 to 3, characterized in that: The plan view is a geological map.

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