Research On Change Detection Method Of Vector Spatial Data Oriented To National Geographic Conditions Monitoring

The change detection technology of vector spatial data plays an important role in GIS data updating.At the same time,it is also a key technology to acquire data change information in National Geographic Conditions Monitoring(NGCM)rapidly and to realize the updating of the geographic conditions data dynamicly.However,there still exists some prominent problems on the change detection for vector data such as low efficiency and accuracy,especially to the demand of NGCM with the larger amount of geographic data.In this paper,a change detection model based on Grid-Based Clustering and Spatial Overlay is put forward.The algorithm of rapid change detection for vector data is implemented,and the theory of change detection for vector data has been developed,which provides supports for the dynamic monitoring of national geographic conditions.The main contents and achievements of this paper are as follows:(1)Having referenced for the theory of change detection for vector data and considered the characteristics of the complicated NGCM data,a new change detection model based on Grid-Based Clustering and Spatial Overlay model(GCNO_CD)is put forward.Through the multi-level detecting algorithm of grid detecting and overlay detecting,the complexity of change detection for vector data has been significantly reduced,thus accelerating the process of change detection and enhancing the accuracy.(2)Based on the GCNO_CD model,the change detecting algorithms for NGCM data are implemented.Firstly,combine with the Detection Quadtree(DQ-Tree),the spatial grid partitioning and spatial index construction are carried out for specific point data,line data and polygon data.Then,given the characteristics of land coverage data,the method of overlay analysis are applied.(3)Using the national geographic census data and the dynamic monitoring data of the region in Lishui,Zhejiang Province,the prototype system of change detection for NGCM data has been designed and implemented.In addition,the efficiency and accuracy of the proposed GCNO_CD model have been verified,which is applicable for the change detection of NGCM data.