Terrain feature extraction at different levels

Pao Yue-kong Library Electronic Theses Database

Terrain feature extraction at different levels


Author: Yan, Jingya
Title: Terrain feature extraction at different levels
Degree: M.Sc.
Year: 2011
Subject: Hong Kong Polytechnic University -- Dissertations
Geomorphology -- Data processing
Department: Dept. of Land Surveying and Geo-Informatics
Pages: viii, 62 leaves : ill. (chiefly col.) ; 30 cm.
InnoPac Record: http://library.polyu.edu.hk/record=b2412273
URI: http://theses.lib.polyu.edu.hk/handle/200/5972
Abstract: Digital terrain analysis in three dimensions has been one of the most important research areas and applications in the geo-information sciences. Describing terrain surface in different levels not only helps to reduce the size of database and improve the efficiency, but also meets the various requirements of digital terrain analysis. The terrain morphological features play an important role in digital terrain analysis. This study aims to extract terrain features at different levels. The data of this project is one part of Port Navalo, in which one part of this area is over sea level and the other undersea. Because the landform is made up of various features, this study classifies the terrain morphological features into four levels, which are point level, line level, area level and shape level. The point level includes peak, pit and pass. The line level has ridge and channel. The area level has plane, which is used to build shape. The shape level contains uphill area, downhill area and flat area. In the segmentation, the slope value and slope direction are used to segment DTM in different levels. In order to represent terrain morphometric features in three dimensions, the feature areas should be merged as shapes. At last, the results of terrain morphometric features extraction have been discussed at the different levels of segmentation. Meanwhile, the partonomy relationship of terrain morphometric is used to classify landform. In addition, different kinds of data structure were used to store the data, attributions and relationships of DTM at the different levels. From the limited technique carried out in this study, some conclusions are made as follows: Based on the partonomy relationship, the three levels of terrain morphometric features can extract and represent terrain morphometric features in the DTM of three demensions. After comparing the terrain morphometric features at different levels of segmentation, it is easy to know the more details of terrain morphomertic features will be detected at the higher levels of segmentation. Meanwhile, based on the partonomy relationship, the different types of shape can be separated and represented clearly.

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