Dynamic tolerance setup method based on scan line arithmetic

A scanning line and tolerance technology, which is applied in the field of scanning line algorithm, can solve problems such as great difference in numerical range, inability to avoid errors, and inability to guarantee correctness, so as to achieve the effect of ensuring correct implementation, ensuring correctness, and accurate geographic information

Inactive Publication Date: 2009-06-17
北京中科通图信息技术有限公司
View PDF0 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the scanning line algorithm cannot avoid the existence of errors in practical applications; and when it is applied in geographic information systems, it may encounter geographical data of different coordinate systems, and the numerical ranges of these data are very different, for example: in units of latitude and longitude If the value is less than 1000; when the unit is kilometers, the value may be tens of thousands; when the unit is meters, the value may be millions
Therefore, the static setting tolerance cannot guarantee the correctness of the scan line algorithm in judging whether the event point is on the line segment

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Dynamic tolerance setup method based on scan line arithmetic
  • Dynamic tolerance setup method based on scan line arithmetic
  • Dynamic tolerance setup method based on scan line arithmetic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0021] Regarding the method of error analysis, the actual situation of scientific calculation is complicated. Each calculation will generate new rounding errors and propagate the existing errors in previous steps, and the number of calculations is often very large, often tens of millions. It is not advisable to simply estimate the monotonous growth, because the error bounds obtained in that way will be far beyond the actual situation, and even completely cover up the useful results. In practical applications, the actual error should be much smaller due to the rounding off in multiple calculations.

[0022] The error transfers of multiple operations are independent of each other, and it is impossible to obtain extreme values ​​at the same time, so an optimistic approach should be used for error analysis. According to the "3σ principle" of normal distribution, the cumulative error of n operations is guaranteed with 99.97% probability:

[0023] | ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention provides a scanning line algorithm, comprising calculating an absolute error of an intersection point coordinate based on a formula for calculating tolerance and a process for calculating a line segment intersection point; calculating a tolerance of whether a judging point is on the line segment or not, based on the formula for calculating tolerance, the absolute error of the intersection point coordinate and the calculating process for determining whether the point is on the line segment or not; determining whether the point is on the line segment or not. The invention can determine the tolerance after floating point number operating, further, under the precondition that the operation of floating point values representing the point coordinate and the line segment and so on exists the error, rightly judging whether the event point is on the line segment or not, thereby ensuring the correctness of the scanning line algorithm.

Description

technical field [0001] The invention relates to a scanning line algorithm applied in a geographic information system, in particular to a dynamic tolerance setting method based on the scanning line algorithm. Background technique [0002] Geographic Information System (GIS) is a specific and very important spatial information system. It is a technical system that collects, stores, manages, calculates, analyzes, displays and describes the relevant geographical distribution data in the entire or part of the earth's surface (including the atmosphere) space with the support of computer hardware and software systems. The core of geographic information system is to process spatial geographic data, including point-surface overlay, line-surface overlay and area-surface overlay. All overlay analysis is based on the processing of associated line segment clusters and line segment intersections. [0003] The scanline algorithm is a classic algorithm that outputs the intersection points ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/10G06F17/30
Inventor 朱效民齐林程振林方金云
Owner 北京中科通图信息技术有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap