Automatic Extracting and Identifying of Point-shaped Symbols on Topographic Map
地形图点状符号的自动提取和识别

This paper presents a new method of extracting and identifying point-shaped symbols of scanned topographic maps based on distance transformation.First,we optimize the extracting results of element maps,and filter the lines which do not meet the features of point symbols according to camber density and line density,and detach the symbols from the map based on shelling transformation and molting transformation.Next,we measure the whole features of symbols by a weighed distance function and the geometry shape feature by the consistence of symbol skeleton,and identify symbols by these two features.The algorithm can identify the shear transform Chinese character and annotations of line symbols.