Digital elevation models (DEMs) cover a wide range of scales, and allow statisticalanalysis of geomorphometric parameters. At global or continental scale, DEMs covering rectangular quadrangles can be considered random samples. Average quadrangle values can be compared at different DEM scales, and for different physiographic provinces. Three independent variables provide valuable descriptions of...

The German satellites TerraSAR-X and TanDEM-X are flying in a close orbit formation as a bistatic interferometer to generate a high precision Global Digital Elevation Model (DEM). DEM data is acquired in bistatic operation with one active satellite illuminating the swath and both satellites receiving the ground echoes. This mode requires synchronization between the independent oscillators on Te...

TanDEM-X is a mission proposal for a TerraSAR-X add-on satellite to enable high-resolution single-pass SAR interferometry. The TanDEM-X mission has the goal of generating a global Digital Elevation Model (DEM) with an accuracy corresponding to the DTED-3 specifications (12 m posting, 2 m relative height accuracy for flat terrain). This paper describes the mission concept and requirements, inclu...

Topographic data collected using RTK‐DGPS‐equipped farm vehicles during field operations could add additional benefits to the original capital investment in the equipment through the development of high‐accuracy field DEMs. Repeated surveys of elevation data from field operations may improve DEM accuracy over time. However, minimizing the amount of data to be processed and stored is also an imp...

Delineation of drainage basins is a popular terrain analysis method for digital elevation model (DEM) data. Currently, a deterministic delineation method is available in a number of terrain analysis software applications. The method uses elevation data for defining flow directions for each elevation point of a DEM and then follows flow paths from a pour point to all upstream points. The influen...

Various methods have been applied to generate Digital Elevation Models (DEM) but whatever method is used, DEM estimates will always be affected by errors. Comparing interpolated values with the actual elevation values, obtained with a high precision field survey, allows us to assess DEM accuracy. At every spot height location it is possible to subtract the actual values from the DEM values to o...

Digital Elevation Models are a central information source for scene analysis, including specific tasks such as building localization and reconstruction. Whatever application is envisaged, DEM segmentation is a critical step, due to the great variability of landscapes and above-ground structures in urban areas. Moreover, a DEM may contain erroneous isolated 3D points, which have to be identified...

Interferometric synthetic aperture radar (InSAR) processing relies on phase unwrapping to convert interferometric phase to topographic height. Phase unwrapping is a di cult non-linear process that is still the subject of on-going research. Rather than processing the complete phase image to extract a digital elevation model (DEM), we use existing coarse DEMs as an integral part of the InSAR algo...

Intercomparison of backscatter collected by SAR sensors at heterogeneous radar look angles gives rise to highly variable ground areas being associated with each pixel location within a radar geometry (slant or ground range) image. Many elements within a digital elevation model (in map geometry) can be mapped to a single location in the radar image (range / Doppler coordinates). An image simulat...

A new Swiss glacier inventory is to be compiled from satellite data for the year 2000. The study presented here describes two major tasks: (1) an accuracy assessment of different methods for glacier classification with Landsat Thematic Mapper (TM) data and a digital elevation model (DEM); (2) the geographical information system (GIS)-based methods for automatic extraction of individual glaciers...