Research On The Space Modeling Based On Data Field

Since GIS was first introduced,space analysis has been an important aspect of GIS.As space analysis is based on space data model,whether to build a good space data model should responsible for the result of space analysis.Nowadays the system of GIS space modeling is not perfect,our research will be hopeful.This paper introduced and compared space modeling methods,including Common Kriging method,Yang Chi-zhong's filtering method,Least Square Collocation method,Inverse Distance Weighted method,Multiple Regression method.Furthermore,this paper adopt matlab 7.0 combine with vc++ has carried out realization on relevance algorithm,and realized the drawing of isoline by openGL. In the algorithm module,the DEM data with any scale can be produced from scatter data,which is of significance.In research of the Kriging method and Yang Chi-zhong method,the problem of Negative-weight was found.The problem was inevitable,and could produce abnormal value.The mathematical model of the Negative-weight was common in quadratic programming,and therefore,this paper studied many algorithms for convex quadratic programming,and finally selected the Quasi-Newton method for solving the problem of Negative-weight which is testified in Matlab 7.0.In this paper, we give two algorithms:nonnegative Kriging method and nonnegative Yang Chi-zhong method.T_ he two methods combined Common Kriging method and Yang Chi-zhong's filtering method with Quasi-Newton method and were proved that the abnormal value could be eliminated.The project of this thesis is supported by"Application of EM Ajustment"of the program"863",this paper has finished the task of space data modeling.In the task,we combined heavy metal elements in Qixian,Shanxi Province,including 396 sampling points in area of about 400 km2,and high atmospheric,temperature,humidity,which are provided by IGS,analysed the result of interpolating by Common Kriging method,Ya_ ng Chi-zhong's filtering method, nonnegative Kriging method and nonnegative Yang Chi-zhong method,testified the problem of Negative-weight.In contrast,it is thought the nonnegative Kriging method and nonnegative Yang Chi-zhong method could improve the precision of DEM and remove abnormal points.