A Laser Altimetry (LIDAR) system aboard an aircraft can yield highly accurate data about the ground surface and vegetation below. Raw LIDAR points must be processed to generate a digital elevation model (DEM), i.e. a digital map of the terrain surface. A number of techniques can be used to generate the DEM, and in this report I investigate several of these including a new algorithm based on rec...

During the implementation of the DGPF-project on Digital Photogrammetric Camera Evaluation a team “Digital Elevation Models” was established. The main goal was to use the test’s framework for documentation and evaluation of the current state-of-the-art on photogrammetric 3D data capture from automatic image matching. During these investigations the accuracy and reliability of DSM rasters and 3D...

Introduction: Martian gullies are defined by [1] to be slope features comprised of an upslope alcove, a midslope channel, and a downslope depositional fan. Due to their relative youth and similarities to waterrelated features on Earth, the Martian gullies have attracted much attention since their discovery by the Mars Orbiter Camera [1]. Many erosional agents for the gullies have been proposed ...

Despite the relatively high cost of airborne lidar-derived digital elevation models (DEMs), such products are usually presented without a satisfactory associated estimate of accuracy. For the most part, DEM accuracy estimates are typically provided by comparing lidar heights against a finite sample of check point coordinates from an independent source of higher accuracy, supposing a normal dist...

We study the accuracy of data on some local topographic attributes derived from digital elevation models (DEMs). First, we carry out a test for the precision of four methods for calculation of partial derivatives of elevations. We ® nd that the Evans method is the most precision algorithm of this kind. Second, we produce formulae for root mean square errors of four local topographic variables (...

A Digital Elevation Model (DEM) represents the height of a patch of terrain. Accuracies of DEMs vary depending upon the requirements of different applications. DEMs have been applied to a wide range of civil engineering and military planning tasks. Besides the conventional methods of creating DEMs, such as photogrammetry and manual field survey, airborne laser scanning and radar interferometry ...

According to the perception that subjects have about geographic objects, people can evaluate their proximity. The answers to the question if a geographic object is near other will be different according to the environment that the objects belong to. Also, when we consider geographic objects that do not have well defined boundaries, the perceptions of people with respect to the distance will be ...

A digital representation of a terrain surface is an approximation of reality and is inherently prone to some degree of error and uncertainty. Research in uncertainty analysis has produced a vast range of methods for investigating error and its propagation. However, the complex and varied methods proposed by researchers and academics create ambiguity for the dataset user. In this study, existing...

In recent years, collection and processing techniques for Digital Elevation Models (DEMs) generation have improved rapidly, allowing surfaces to be represented with more detail and accuracy. Fusion of overlapping DEMs, generated from data captured with different acquisition techniques, or from different times, allows to find inconsistencies, improve density, accuracy and currency, and eliminate...