A Study Of Extracting Terrain Character Lines Automatically And Exchange Of Data Format

With the developments of Geographic Information System, Digital Elevation Model, as a kind of base data of Geographic Information System, plays more and more important role in the geoscience area, and it has already become an important component of the Geographic Information System. The quality of Digital Elevation Model is the priority factor in determining use value. At the same time, extracting terrain character lines automatically and exchange of data format are worthy to research. In this paper, the main works include:Firstly, the author discusses the theories and methods on constructing high quality Digital Elevation Model based on terrain feature from digital contour line. The main problems and current research of DEM are analyzed, extracting terrain character lines automatically and exchange of data format are the main directions in current research and application, which vital theory and methods based on are the base of this thesis.Secondly, on the basis of referencing the theories on cartographic generalization, the author makes the study and experiment on automatic extraction of terrain character lines from digital contour by using principle and method of curve. The implementation process explained in detail include segmentattion of contour lines by inflection point, extraction of character points segment-by-segment,link terrain character lines by attribute.Thirdly, in order to improving modeling efficiency and model accuracy, the author studies the method on constructing high quality Digital Elevation Model based on different vector data, involve common algorithms of constructing TIN based on irregular discrete points,modeling method and improving measures on constructing constraint D-TIN considering the terrain character, algorithms of constructing TIN based on contourlines.Nextly, theory and methods on constructing Regular Grids based on Various data sources are researched, and the interpolation algorithm - Smoothing Function interpolation arithmetic of interpolating Regular Grid DEM from Triangulated Irregular Network is improved.Finally, Universal algorithm of tracing contour line automatically from Triangular Irregular Network and Regular Grids are researched. According to the similar topological relations of the two kinds of data storage format, universal algorithm is point out to tract contourlines from these two data Format.At last, the paper summarizes research productions and development direction.