Vertical Accuracy Assessment of ALOS PALSAR, GMTED2010, SRTM and Topodata Digital Elevation Models

Three-dimensional data of the Earth's surface can support several types of studies, such as hydrological, geomorphological, environmental monitoring, among many others. But, due to the difficulty of acquiring these data in the field, freely available Digital Elevation Models (DEM) have been widely used, and therefore, it is increasingly necessary to check their accuracy to ensure their correct applicability according to the appropriate scale. However, there are no studies which have assessed specifically the vertical accuracy of the ALOS PALSAR, GMTED2010, SRTM and Topodata DEMs according to Brazilian Cartographic Accuracy Standard (PEC). In this sense, this paper aims to evaluate the quality of the above-mentioned DEMs by using the official high accuracy altimetric network data of the Brazilian Geodetic System. Statistical analysis of errors results demonstrated that the DEMs have applications compatible with 1:100,000 scales or smaller than this, and although the GMTED2010 presented a lower accuracy than the other DEMs, it also could be classified in the same accuracy category according to the Brazilian PEC. We conclude that DEMs assessment is very important to ensure their correct application as they can be used in many researches since these data are available for practically all areas of the planet.