Geospatial Techniques for Terrain Analysis of Gombe State, Nigeria

Terrain analysis is useful in so many areas ranging from military operations to landuse and agricultural planning, urban planning, forestry management, drainage, hydrology and site suitability assessment of agricultural, settlement, industrial and transportation projects. Gombe State is one of the newest states in Nigeria; they need industrial growth, agricultural development, transport planning and development and most especially sustainable use of the general environment, hence, the state is in need of reliable spatial information of the terrain. SRTM DEM data acquired online was used in conjunction with other complimentary maps of Gombe State to analyze the terrain of the State in ArcGIS environment. The raster surface modules of ArcGIS 9.3 was used in this paper to generate, classify and analyze the Digital Elevation Models (DEM) using the SRTM data of the state into four classes: highlands, uplands, plains and river basins. Cultural features such as settlement and transportation were also analyzed, while various topographical features such as DEM, slope, hill-shading and contour lines were derived from the DEM data for the analysis of the terrain of the state. The 2013 NIGER_SAT image of the state was classified into six landuse and landcover classes through the classification modules of ERDAS IMAGINE 9.2 for the analysis of the vegetation and landcover of the state. The study revealed that 33.06% and 34.81% of the land area of Gombe State comprised of the River Basin and plains respectively, while 26.65% and 5.48% are of uplands and highland areas respectively. Yamaltu/Deba, Funakaye and Balanga LGAs have more than half of their land area located within the Basin of River Gongola, while Kaltungo, Balanga and Shongom have more highland areas than the other LGAs. It was recommended that remotely sensed data and GIS techniques be used for terrain analysis because of its accuracy and reliability of data output, and its time saving over conventional methods.