GPU-based method for drawing linetype map symbol with gradually-varied width

Abstract

The invention relates to a symbolization rendering technology in the GIS field and the digital map drawing field, provides a GPU-based method for drawing a linetype map symbol with a gradually-varied width, and realizes efficient rendering and drawing of gradual varying on width of a linear vector element based on the method. The method comprises the following steps: firstly determining a coordinate sequence of the line element needing to be drawn, initializing maximum and minimum line widths, according to the maximum width, building a line triangulation network subjected to triangularization, and transmitting a U parameter along a line direction and a V parameter vertical to the line direction to each vertex in the triangulation network; according to a map symbol unit needing to be filled, generating a corresponding color structural table, and transmitting the color structural table, a U-V parameter, the maximum line width and the minimum line width into a tinter program; by using Shader language, according to a U-V value on each vertex and the line widths, drawing pixels of the line element one by one based on a specified width gradual-varying function, thus realizing drawing of the vector linetype map symbol with the gradually-varied width.

Description

technical field [0001] The present invention relates to a symbolic rendering technology in the field of GIS and electronic map, and provides a method for drawing map symbols of width gradient line type based on the GPU (Graphics Processing Unit) programmable pipeline Shader language, and realizes the method based on the method. High-quality rendering and drawing of wide linear vector elements, which can smoothly express feature entities such as rivers and boundaries that have gradient attributes in space. Background technique [0002] The symbolization method of geospatial entities is an important research content in the field of geographic information and cartography. Compared with commonly used point symbols and surface symbols, line symbols are often more difficult and time-consuming because they need to be filled and drawn along the direction of linear elements. In addition to the commonly used solid lines and dashed lines, the line symbols required in map representatio...

AI Technical Summary

Problems solved by technology

This gradual widening drawing needs to be adapted to a variety of line map symbols, and the original vector line data cannot be changed

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