Drawing method for vector graphic map symbols

Abstract

The invention relates to a computer drawing method for vector map symbols with image smoothing characteristic. In the method, the image display characteristic is analyzed by taking image characteristic of aliasing phenomenon of the vector map symbol on a display device as a start point under the condition that the resolution of the device is not increased; and the vector map symbol is smoothly drawn through sampling and image filtering according to categories of points, lines and planes of the map symbol. The drawing method overcomes the defects of rough display of the conventional vector mapsymbol and large superimposition display contrast with image data and the vector drawing is converted into image processing and output, so that computer fine drawing of all map symbols can be realized and the drawing method has great significance for the field of geographic information visualization.

Description

technical field [0001] The present invention belongs to the technical field of geographic information, and more specifically relates to a computer drawing method for multi-grayscale smooth display of vector graphics, in particular to a vector map symbol displayed on a computer using a raster graphics display after multi-grayscale smoothing processing Methods. Background technique [0002] Map symbols are the basic means to express the content of maps. They are composed of graphics or characters of different shapes, sizes, and colors. They have a clear reference to geographical elements and are important clues for visual perception of maps and important for interpreting maps. The basis is an important content of the visual expression of geographic information. At present, geographic information system (GIS) and various map software mainly use map symbols to complete the symbolic expression of geographic information. Except for a small number of point symbols that use picture...

AI Technical Summary

Problems solved by technology

There are the following deficiencies: first, the geometric description of the graphics in the object space must be known, and anti-aliasing smoothing cannot be performed on unknown or complex graphics, such as TrueType characters; second, the geometric graphics known in the object space Even if it is processed, it can only achieve smooth processing of lower gray levels (generally no more than 3 gray levels)

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