AN INVESTIGATION INTO MAPPING WETLANDS FROM SATELLITE IMAGERY – A CASE STUDY IN THE MIDMAR SUB CATCHMENT, SOUTH AFRICA

摘要

Wetlands are important components of a hydrological ecosystem due to their flood mitigation and sediment control capabilities as well as being an important biodiversity node. As a signatory to the Ramsar convention, South Africa is obligated to conserve wetlands. Conservations attempts therefore need to be concentrated on mapping, inventory and monitoring. In South Africa sporadic projects have attempted to map wetlands in different areas, but these have lacked a holistic scientific approach that focuses on the wetland as a dynamic spatial entity in a varied landscape. This paper tests a procedure to map wetlands in the Midmar catchment in South Africa using both summer and winter Landsat ETM data. This study concluded that LANDSAT ETM+ satellite imagery was useful for detecting both large and small wetlands areas during summer by using a fine classification method of 255 classes. The study also concluded that ancillary data such as a DEM, rainfall data and land surveyed verified data played a decisive role in aiding the classification and promoting the identification of wetlands