A Research Of Land-use Change Span Updating Based On Android Platform

Land use span updating is to do field survey of change spans in land use,and then update the grid data of land use span to the database.In the current update of land use maps,field investigators usually need to take a GPS walking site to collect points,manually record the spot attributes,and then manually process the collected data.The above-mentioned work is tedious,labor costs are high,and errors occur.In view of the above problems,this paper studies the land use span updating technology,which can help the field investigators to automatically generate the vector data of land use span with high accuracy in the target area,avoiding a lot of boring manual collection.The key technologies of land use span updating based on Android include the analysis and registration of vector data as well as raster data based on Android,the automatic vectorization algorithm based on multiband and the design and implementation of land use span updating technology.In the analysis and registration of vector data as well as raster data based on Android,this paper studies format and acquisition method of vector data as well as raster data on Android platform,and then studies the registration and maintenance method of vector data as well as raster data coordinate system based on Android platform.In automatic contouring algorithm,GVF algorithm,boundary tracking algorithm based on topological analysis,adaptive Canny algorithm and so on are combined to meet the requirement of real-time extracting and updating of contours in mobile terminal.Aiming at the situation that GVF algorithm is easy to be disturbed by noise,the image is closed and the Gaussian blurring is dealt with in conjunction with the smoothness of the land use span.Aiming at the loss of spectral information when the original algorithm is applied to grayscale,the algorithm above add RGB spectral information to solve this problem.Aiming at the huge computational complexity and problem that is easy to fall into the false edge,using the edge tracking algorithm based on topological analysis proposed by Suzuki and Abe(hereinafter referred to as SA algorithm),the initial contour is extracted,which greatly reduces the computational complexity and improves the accuracy of the algorithm.Aiming at the calculation of the gradient vector field of the traditional GVF algorithm,an adaptive Canny algorithm is used to calculate the gradient map to improve the accuracy of the algorithm.After that,the algorithm calculates the contours of the land use spans into vector format to save and update.Finally,based on the above algorithm,the design and implementation of the land use span update system based on Android platform is realized.The system can collect span data rapidly with Android mobile devices with 3S technology.The system,which benefit from its portability,can effectively improve the degree of automation,real-time and accuracy of land use patch update and reduce the intensity of field survey work and the working time of in-house work.