In developing countries there is a general lack of environmental data for land resource appraisal. Digital terrain modeling is increasingly being used to assist land survey and mapping procedures. Until recently, the only available source of elevation information in Nigeria has been topographic maps, but these are not countrywide. The worldwide 30-foot digital elevation model (GTOPO30) from the U.S. Geological Survey provides a digital alternative to analog topographic maps, but only at a coarse one-kilometer resolution. This paper explores how far GTOPO30 can be used for digital terrain modeling to map landform units and features for a case study catchment in southeastern Nigeria. Comparison is made with digital terrain modeling using digitized 1:50,000-scale topographic maps and aerial photograph stereoscopic analysis, with field surveying. ARC GRID commands are used to derive, statistically explore, and utilize terrain attributes.