Analyses of Watershed Characteristics Based on Different Sources of Digital Elevation Model

Watershed characteristics, such as hydraulic length, total area, total river length and perimeter, can be obtained from an analysis of a Digital Elevation Model (DEM). There are many sources of DEM. In this study, DEM were obtained from two different sources, i.e. Jabatan Ukur dan Pemetaan Malaysia (JUPEM) and Google Earth (GE). The attributes examined in this study include the shape and area of a watershed (km(2)), total river length (km) and hydraulic length (km) of the river using a Geographical Information System (GIS) software. The data from JUPEM was used as the benchmark. It was found that the extracted DEM from GE showed encouraging results. The hydraulic length of the rivers reached very good argument, with only a 3% difference when compared to JUPEM. Additionally, the shape of watershed from GE was slightly smaller than JUPEM, with a difference of about 17%. This study concludes that the DEM from GE can be used as an alternative source of DEM data, especially for studies related to hydrology.