The magnitude of absolute and relative errors of DEMs data has been examined. The absolute accuracy is a measurement of the error between a DEM and the coordinates of the terrain. Accuracy is evaluated by indices such as the absolute mean error (AME), standard deviation (SD) and the root mean square error (RMSE), whereas shape reliability is evaluated through statistical analysis of a parameter set characterizing the spatial properties of a surface such as slope and aspect. Absolute accuracy is expressed as the vertical RMSE, who is an overall error indicator that takes into account both random and systematic errors introduced during the data generation process. The relative vertical accuracy is especially important for derivative products that make use of the local differences among adjacent elevation values, such as slope and aspect. A DEM with good relative accuracy is one that models the shape and dimensions of the terrain accurately, but may not necessarily be accurately registered to real geographic coordinates. The relative accuracy is expressed as the standard deviation of the vertical error [Jung Hum Yu, 2011]. The accuracy of the DEM95 is determined as the difference between the CPs and DEM95 and is denoted as CP - DEM95; similarly, the accuracy of the ASTER and TINITALY is denoted as CP - ASTER and CP - TINITALY. In order to describe and compare the elevation distributions in each DEM, elevations at the locations of CPs have been extracted from all DEMs and compared with the elevations of CPs to determine several descriptive statistic measures.