Research On DLG Geometric Accuracy Decrypt Model Based On Radial Basis Functions

Digital Line Graphic(DLG)is the vector data set of fundamental geographical data.It has been widely use in urban planning,electronic maps,land surveys and many other areas.As a strategic resource of national information,DLG data plays an important role on social development,economic development and national defense,which require decryption and other technical means to turn secret surveying achieve-ment into public surveying result for public use.DLG data characteristics,relevant policies and regulations and decrypt ways pro-pose the need of reduce accuracy,security,maintaining topological and decryption reversible.According the application range,geometric precision decryption can be divided into global geometric precision decryption and local geometric precision de-cryption.This paper propose that global transform geometric precision decryption model should satisfy smooth continuous,control points precise correction and high security.Local geometric precision decryption model should satisfy transform com-pactly supported,smooth continuous and control points precise correction.This paper analysis existing global and local geometric accuracy decryption models,proposed its shortcomings.On the basis of analysis of the existing models,this paper proposed a global geo-metric accuracy decryption and recovery model based on radial basis functions(RBF),and a local geometric accuracy decryption and recovery model based on compactly supported radial basis functions(CSRBF).In addition,this paper proposed an itera-tive control of decryption error algorithm and discrete topology maintenance algorithm in data decryption.The main research contents and conclusions are as follows:1.Research of DLG global geometric precision decryption model.Based on analysis of DLG data model,China's decryption policies and decryption methods,this paper study global geometric precision decryption model.Using radial basis functions to constructed DLG global geometric precision decryption model.Then proposed restoration model using two ways of inverse iteration by decryption parameters and obtained restoration parameters by decryption parameters.2.Research of DLG local geometric precision decryption model.Based on the study on the characteristics of local geometric precision decryption,this paper study local geometric precision decryption model.Using compactly supported radial ba-sis functions to constructed DLG local geometric precision decryption model.Then proposed restoration model using inverse iteration by local decryption parameters.3.Research of decryption error control algorithm.This paper analyzes the re-lationship between the decrypt model parameters and decryption data's root mean square(RMS),then present an algorithm to control RMS by iterative to ensure global and local geometric precision decryption data's RMS to meet the requirements.4.Research of discrete topology maintenance algorithm in DLG geometric pre-cision decryption.For the discrete characteristic of DLG data,this paper proposed topology maintenance algorithm in nonlinear transform.This paper applied the algo-rithm in global and local decryption to maintain the topological incariant.