Use of thematic mapper imagery with a geographic information system for geomorphic mapping in a large deltaic lowland environment

Landform mapping in the deltaic lowland environment is complicated by the rapid and significant changes of many fluvial forms and lowland coasts and the poor topographic expressions of the landforms. The timely updating of landform maps is of criticalsignificancebeyond geomorphology itself, into broader fields of environmental management and sustainable development. Existing techniques need to be tailored and refined towards the operational mode for full functioning of landform mapping. This study presents an example of the application of Landsat Thematic Mapper (TM) data and image processing and geographic information system (GIS) techniques to geomorphologic mapping in a large deltaic lowland environment. Data acquisition, processing, integration, analysis, interpretation and presentation were performed under a GIS environment, in which a terrain mapping unit database linking both geospatial and attribute data was built up. A terrain classification map was produced and further validated with Global Positioning System-guided field checks and observations. Results show that TM interpretation with a GIS allows an accurate geomorphological classification of terrain in accordance with the level of mapping scale used. With some caution, this method might be used in highly dynamic deltaic environments.