טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentLichtenstein Alon
SubjectAccuracy Analysis of DTMs Combined with Breaklines
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Yerach Doytsher


Abstract

Digital Elevation Databases (DED) constitute a central component of the great boost to all mapping and GIS fields, as the variety of applications that are supported by it is practically infinite. A variety of sophisticated Technologies brought a huge availability of automatic elevation data. The surface data obtained applying these automatic techniques is not sufficiently reliable, and requires addition characteristic data such as break-lines. Merging break-lines and DTM is a part of a bigger challenge of modeling three-dimensional surfaces. An analysis is presented on the improvement in the accuracy of surface representation after applying different techniques for break-lines incorporation. Numerous experiments were carried out in different areas, based on very accurate measurements, which enabled profound analysis and conclusions. The research demonstrates a proven ability using sparse grids combined with break-lines for reliable and accurate modeling. Two appropriate techniques are proposed for merging break-lines with DTM. The first one, some how, extend the existing (commercial packages) technique, while the other one has been developed to combine DTM and break-lines in a different approach. The two proposed techniques represent two different approaches for DTM and break-lines incorporation, described in the theoretical review. One of the major conclusions of the research is that a combination between the two techniques, will, probably, yield the best resultant surface. Comparative reports of the proposed techniques as well as efficiency analysis comparing the cost-effectiveness of sparse grids merged with break-lines verses dense grids are presented. Some future research activities dealing with the challenging field of modeling elevation data are also proposed.