Evaluation of digital surface model using digital elevation models

Madhusudhan, K (2014) Evaluation of digital surface model using digital elevation models. Masters thesis, Manipal Institute of Technology, Manipal.

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Digital elevation models (DEMs) have been an important topic in geography and surveying sciences for decades due to their geo morphological importance as the reference surface for gravitation driven material flow, as well as the wide range of uses and applications. When DEM is used in terrain analysis, for example in automatic drainage basin delineation, errors of the model collect in the analysis results. Investigation of this phenomenon is known as error propagation analysis, which has a direct influence on the decision-making process based on interpretations and applications of terrain analysis. Additionally, it may have an indirect influence on data acquisition and the DEM generation. The focus of the thesis was on the fine toposcale DEMs, which are typically represented in a 800-1000m grid and used in the application scale 1:10 000-1:50 000. The thesis presents a three step framework for investigating error propagation in DEM based terrain analysis. The framework includes methods for visualising the morphological gross errors of DEMs exploring the statistical and spatial characteristics of the DEM error, making analytical and simulation-based error propagation analysis and interpreting the error propagation analysis results. The DEM error model was built using geo statistical methods. The results show that appropriate and exhaustive reporting of various aspects of fine toposcale DEM error is a complex task. This is due to the high number of outliers in the error distribution and morphological gross errors, which are detectable with presented visualisation methods. In addition, the use of global characterisation of DEM error is a gross generalisation of reality due to the small extent of the areas in which the decision of stationary is not violated. This was shown using exhaustive high-quality reference DEM based on airborne laser scanning and local semi variogram analysis. The error propagation analysis revealed that as expected an increase in the DEM vertical error will increase the error in surface derivatives. However, contrary to expectations, the spatial autocorrelation of the model appears to have varying effects on the error propagation analysis depending on the application

Item Type: Thesis (Masters)
Subjects: Engineering > MIT Manipal > Instrumentation and Control
Depositing User: MIT Library
Date Deposited: 13 Nov 2014 10:45
Last Modified: 13 Nov 2014 10:45
URI: http://eprints.manipal.edu/id/eprint/141063

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