Drawing method for complex linear symbol pattern unit

Abstract

The invention provides a drawing method for a complex linear symbol pattern unit. The method comprises the following steps of: step 1, determining a basic element of a complex linear symbol to be drawn; step 2, determining an unallocated basic element length; step 3, calculating the number of basic elements which can be accommodated in the unallocated length of the basic element, calculating the modified basic element length; step 4, judging whether the modified basic element length meets the allocation requirement; step 5, gradually processing length variation; step 6, calculating whether a bounding rectangle of the basic element, of which length variation is gradually processed, intersects with a neighboring angular bisector. In the method, by the classification of virtual parts and the real parts of the linear symbol elements and the introduction of visual limited insertion variation, the linear symbols are processed more flexibly, thus the visual sense of continuity of the linear symbols at an inflection point part is enhanced; different processing methods are selected according to the threshold of the number of elements drawn between two inflection points, so that the complexity of the processing procedure is simplified, and the processing phase can be more efficient.

Description

technical field [0001] The invention belongs to the technical field of linear symbol drawing in a GIS system, and in particular relates to a drawing method for complex linear symbol pattern units. Background technique [0002] In recent years, with the development of computer science and technology, the development of geographic information system (GIS for short) is also making great strides forward. In the GIS system, great emphasis is placed on the processing and analysis of spatial data and the interaction between humans and machines based on spatial data. Based on this requirement, the visualization of GIS should be one of the functions that the geographic system should have. [0003] GIS processing methods for spatial data mainly include data input, update, maintenance, display, analysis and mapping. The GIS system provides spatial data to the user in the form of simple geometry composed of points, lines, and surfaces, so that the user can conduct effective analysis a...

AI Technical Summary

Problems solved by technology

At present, many computer softwares are made by circulating the basic units of these linear symbols in a certain order and interval along the positioning line. This method will cause some problems at the inflection point: first, the linear symbol may be at the inflection point. Very serious deformation occurs, such as incomplete drawing of basic primitives at the inflection point of the national boundary line, and out-of-shape at the bend; secondly, when the angle of the positioning line is small, the pattern will have serious self-intersection or overlap , such as the crossing phenomenon of symbol elements appearing at the inflection point of small angle symbols; thirdly, some line symbols may have blank inflection points where the trend of the positioning line changes significantly, resulting in visual discontinuity of the line symbols, giving people With the sense of fracture, the visual aesthetics of the symbol is not strong, such as the blank phenomenon at the inflection point of the seasonal river symbol

[0005] Patent Publication No. 101783022A "Integral Road Network Symbolization Method Based on Painter's Algorithm" discloses the structure method of linear symbols and proposes a color rendering method for simple linear symbols, but there is no such thing as a design method for complex linear symbols. mention

Due to the particular complexity of the linear symbol structure, the above method cannot be used as a general solution for linear feature configuration

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