Extraction And Processing Of Contour Lines In Color Scanned Map

Topographic contour lines is an important part of map information, the automatic extraction of contour lines from color scanned topographic map is one of the key techniques of geographic data attainment. Firstly, the color modal and its conversion are discussed thoroughly. The algorithms of color segmentation available are researched earnestly and valued rightly. Base on map algebra theory, this paper brings forward a new method of color segmentation: automatic color segmentation of real color topographic map based on minimal cover.The brown map that includes contour lines has many conglutinations and ruptures due to the map own quality, scanned effect, overlay of other map objects. Because of the bad quality of contour line map, the work of contour lines extraction and recognition from color map becomes very hard. This paper improves on the current thinning algorithm aiming at the contour characteristic and resolves the contour conglutinations successfully. The causation of contour ruptures is researched earnestly and this paper gives some reserved methods.