Urban Built-up Area Boundary Information Extraction And Spatial Expansion Analysis

Based on Landsat images,the study explores the concept and definition of built-up areas through literature review.With the help of RS and the best RGB combination,spatial,spectral and texture information of buildings of Tangshan is studied.Through the multiple experiments to determine the segmentation scale,the object-oriented of constructing interpretation rule by constructing the remote sensing index was used to extract the boundary.By visual contrast and accuracy,it was found that the accuracy of object-oriented is between maximum likelihood and SVM,but the spots are obviously less,and the boundary is more complete and continuous.Therefore,it is feasible to extract the boundary by the rule-based object-oriented classification method.Based on the information of the boundary of Tangshan extracted from 5 images,with GIS,the expansion and change of built-up areas of Tangshan center and county are analyzed from the aspects of expanding quantity,space form,expanding direction difference and rationality.The statistics quantitatively analyzed the driving factors for the expansion of built-up areas in Tangshan.The main results obtained are as follows:The expansion model of Tangshan center is high-speed epitaxy and high-speed filling alternation;the center of gravity is migrating to the northwest as a whole;the spatial forms are becoming more discrete and the internal relations are relatively distant;the differences in expansion direction are relatively large;the direction of expansion is quite different;the speed of expansion is not compatible with the population growth.The expansion difference of Tangshan counties is gradually narrowing.Counties are high-speed expansion,among of which the annual average expansion rate of Zunhua is the fastest and Qianxi is the slowest;all built-up areas become discrete,and boundary tends to twists and turns;Qian'an has relatively close internal links,while Luannan is the loosest;Direction differences of expansion are greater,but intensity and the scale difference are gradually reducing.The study suggests that the main driving forces for the expansion of Tangshan are economy and industrial structure after the earthquake,followed by the transportation development and construction industries,and the population and environmental factors have weak driving effects.