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A tolerance value-based line segment space relation detection algorithm and equipment

A technology for detecting algorithms and spatial relationships, applied in the field of surveying and mapping geographic information, can solve problems such as waste of resources, ignoring tolerance factors, and ignoring computer expression error factors, and achieves the effect of improving computing performance and improving computing process.

Pending Publication Date: 2021-09-17
北京地星伟业科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, there are three problems in the efficient judgment algorithm of line segment spatial relationship in computational geometry and computer graphics. The reason for rounding is that the actual intersection point may not be on a straight line; the second is that the tolerance factor is not considered, because the digital products produced have different drawing scales, the coordinate values ​​of the geometric objects and the topological relationship judgments between the line segments are different. Accuracy requirements, when the tolerance is not considered, the coordinate value of the geometric object is expressed with the highest precision of the computer, and the topological relationship between the line segments is also a strict geometric relationship, which not only causes unnecessary waste of resources, but also has spatial relationship judgment results that do not conform to The actual demand is wrong; the third is that the performance of the algorithm is unstable. The line segment relationship judgment algorithm has a high execution frequency in the geographic information software system, and the geometric forms that need to be calculated are diverse. It needs a processor platform that supports multiple terminals with different computing capabilities. The algorithm in the stage does not take into account the computational time complexity and space complexity under the combined influence of the above factors

Method used

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  • A tolerance value-based line segment space relation detection algorithm and equipment
  • A tolerance value-based line segment space relation detection algorithm and equipment
  • A tolerance value-based line segment space relation detection algorithm and equipment

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0233] Example 1 The circumscribing rectangles corresponding to the two line segments do not intersect within the tolerance range

[0234] image 3 It is a schematic diagram of judging by this algorithm that the circumscribing rectangles corresponding to two line segments do not intersect within the tolerance range. The dotted line in the figure is the enlarged rectangle of the circumscribed rectangle of the line segment Q according to the tolerance value tolerance. If it does not intersect with the circumscribed rectangle of the line segment P within the tolerance range, it can be determined that the line segment P and the line segment Q must not intersect, and the return value of the algorithm is NO_INTERSECTION.

Embodiment 2

[0235] Embodiment 2 The circumscribing rectangles corresponding to the two line segments intersect within the tolerance range

[0236] Figure 4 It is a schematic diagram of judging by this algorithm that the circumscribing rectangles corresponding to two line segments intersect within the tolerance range. The distance from the endpoint Q1 of the line segment Q to the line segment P is less than the tolerance value tolerance. The distance value can be the minimum distance from a point to a line segment, or the difference between the intersection point and the point's horizontal and vertical components of the minimum distance from a point to a line segment. Different defined distance values ​​can be selected according to the needs of the algorithm in application.

Embodiment 3

[0237] Embodiment 3 The circumscribing rectangles corresponding to the two line segments intersect within the tolerance range

[0238] Figure 5 Indicates a geometric relationship in which the circumscribing rectangles intersect but the line segments do not intersect. The line segment Q crosses both sides of the line segment P, and the corresponding circumscribing rectangle intersects, and the distance between the endpoint P2 of the line segment P and the line segment Q is greater than the tolerance value, so the two line segments do not intersect.

[0239] In the above three embodiments, image 3 , Figure 4 , Figure 5 Represent different geometric relationship types between two line segments: image 3 Indicates a geometric relationship in which the circumscribing rectangles of two line segments do not intersect within the tolerance range, and the line segments must not intersect. Figure 4 It represents a geometric relationship in which two line segments do not intersect...

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Abstract

The invention discloses a tolerance value-based line segment space relation detection algorithm and equipment, and the algorithm comprises the following steps: firstly, judging whether external rectangles corresponding to two line segments are intersected in a tolerance range, then, judging the collinear intersection condition, then, judging the single-point intersection condition, and finally, carrying out a straddling experiment, and judging whether the external rectangles are intersected or not. According to the process, the number of judgment times is reduced according to actual application experience, comparison operation is preferentially adopted, reusable calculation values are stored, and high calculation performance is achieved. According to the invention, a tolerance parameter is introduced into a line segment space relation judgment algorithm, is used for improving a data processing geometric engine algorithm, and can also be directly used for a geography analysis algorithm of various geographic information software; according to the invention, all technical links penetrating the upstream and the downstream of a geographic information software technical chain, such as a line segment space relation judgment node, a geographic unit space relation judgment node and a production application node, in a geographic information data production management technical route are realized.

Description

technical field [0001] The invention belongs to the technical field of surveying and mapping geographic information, and relates to a plurality of important algorithms in the geometric engine of geographic information data, which are applied to the validity judgment algorithm of simple geometric objects of geographic information vector data, the spatial topology relationship judgment algorithm, and the spatial superposition processing algorithm, etc., specifically It refers to a line segment spatial relationship detection algorithm and equipment based on tolerance value. [0002] technical background [0003] The geographic information data model expresses continuous geographic entities with discrete spatial data, including vector data models, raster data models, grid data models, and vector-raster integrated hybrid data models. Among them, the vector data model includes geometric objects such as points, lines, and planes. The vector geographic information data generated acco...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F16/245G06F16/29G06F16/28
CPCG06F16/245G06F16/29G06F16/284
Inventor 张贝文俊凯郭杰
Owner 北京地星伟业科技股份有限公司