Practical use of SRTM data in the tropics – Comparisons with digital elevation models generated from cartographic data

Abstract

Topography is basic to many earth surface processes. It is used in analyses in ecology, hydrology, agriculture, climatology, geology, pedology, geomorphology, and many others, as a means both of explaining processes and of predicting them through modeling. Our capacity to understand and model these processes depends on the quality of the topographic data that are available. Most countries have much of the land surface covered by cartographic maps at varying scales and of varying accuracies. In most tropical countries, these maps are produced through manual interpretation of stereo pairs of aerial photos, and in some cases the topographic data can be erroneous or missing where cloud was present. With the advent of satellite imagery covering the globe, various global datasets of topography have been produced, of increasingly better resolution, from 10 arc-minutes (approximately 18 km at the equator) to 30 arc-seconds (approximately 1 km at the equator) using the United States Geological Survey (USGS) product, GTOPO30. This topography dataset was widely used for almost a decade, mainly for broadscale assessments. However, the 1-km spatial resolution prevented its use in modeling more detailed earth surface processes, especially in fields such as hydrology, pedology, or small-scale geomorphology. Researchers in these areas had to rely on local maps for the topography. Digitization or photogrammetry, time-consuming and costly processes, was needed to produce high-resolution digital elevation models (DEMs)...