A Research And Realization For Vector Of Bar Images In Geography Information System

On the demand of vector electronic maps in the geography information system, this paper designs and realizes a vector system of paper topographic maps. By means of math morphology and theories connected with it, the paper succeeds to separate the scanning image and classify the linear elements which have the same type but different width in the scanning. In the thinning of the target image, an edge detection method based on four structure elements template and a morphological sequential homotypic skeleton abstraction method based on eight structure elements template are developed. These methods adopt the parallel processing manner and improve the rate of thinning at the same time upgrade the image processed. As the result of the framework of the thinning, vector method is formed in which its track is monitored by using dynamic change of pace about Freeman's chain code. Under the premise of ensuring its accuracy of point positions, this algorithm has many advantages, such as faster rate, higher accuracy and less storage space.