Geographic Information Systems (GIS)-based spatially distributed model for runoff routing

A method is proposed for routing spatially distributed excess precipitation over a watershed to produce runoff at its outlet. The land surface is represented by a (raster) digital elevation model from which the stream network is derived. A routing response function is defined for each digital elevation model cell so that water movement from cell to cell can be convolved to give a response function along a flow path and responses from all cells can be summed to give the outlet hydrograph. An example application of analysis of runoff on Waller Creek in Austin, Texas, is presented.Waller Creek Working Grou

Mapping Terrestrial Impact Craters with the TanDEM-X Digital Elevation Model

The TanDEM-X mission generates a global digital elevation model (DEM) with unprecedented properties. We use it for mapping confirmed terrestrial impact craters as listed in the Earth Impact Database. Both for simple and complex craters detailed investigations of the morphology of the particular structure and of the surrounding terrain can be performed

Pembuatan Digital Elevation Model Resolusi 10m dari Peta RBI dan Survei GPS dengan Algoritma ANUDEM

This study proposes the generation of Digital Elevation Model (DEM) with spatial resolution of 10m x 10m by re-interpolation of elevation data. Data input for this study includes: (1) digitized datum coordinate from RBI map, (2) sample points surveyed by GPS, (3) digitized contour data fromSRTM DEM and ASTER GDEM2, and (4) digitized stream-network layer from RBI. All collected data were converted to mass point coordinats. On the top of Topogrid-ArcGIS, all points data were interpolated to produce DEM. After that the produced DEM were compared and evaluated to the SRTM and ASTER DEMvisually. The result shows that produced DEM are more accurate to represent the detailed topography of the study areas

Height Accuracy of Radargrammetric Generated Digital Elevation Model

The stereoscopic concept used in photogrammetry was successfully extended to the optical sensor of SPOT (System Probatoire d'Observation de la Terre) to generate the digital elevation model (DEM) and to extract the planimetric features. Following this success, scientists are impressively encouraged to explore the feasibility of using stereoscopy on synthetic aperture radar (SAR) images, applying the radargrammetric technique. In the regions where cloud cover or darkness prevails, active microwave remote sensing data such as SAR can be fully utilized to procure information about land surface and forest canopy. The objective of this study is to analyze the accuracy of the elevations extracted from the DEM generated using the radargrammetric technique as compared with the elevations generated from the photogrammetric technique. The capability of the radargrammetric technique and its potential in extracting the altimetric information were subsequently assessed. The stereo RADARSAT images of Klang Valley with coverage of 100 Ian by 100 Ian were acquired. A total of 199 Ground Control Points (GCPs) were selected on relatively low terrains as backscattering radar data is very sensitive to the slope and high terrains. The primary input data was the coordinates of GCPs which were extracted from the topographical maps. When the errors produced in the GCP collection report were acceptable, the next process was creating epipolar images and generating DEM. It was then followed by generating the geocoded DEM

Influence of camera distortions on satellite image registration and change detection applications

Applications such as change detection and digital elevation model extraction from optical images require a rigorous modeling of the acquisition geometry. We show that the unrecorded satellite jitter during image acquisition, and the uncertainties on the CCD arrays geometry are the current major limiting factors for applications requiring high accuracy. These artifacts are identified and quantified on several optical satellites, i.e., SPOT, ASTER, QuickBird, and HiRISE

Bathymetric digital elevation model for the Tennessee River

A seamless digital elevation model (DEM) of Chattanooga, TN containing the Tennessee River bathymetry was needed for a hydrodynamic modeling project. Geospatial bathymetric data for the Tennessee River was not available in digital form. Depth contour maps downloadable as a PDF files were the only readily available data. A strategy was thus developed to create a GIS of the contour maps and “burn in” this bathymetry data into USGS DEMs which lack information on river depth. Two PDFs were digitized pertained to “Nickajack Lake” and “Chickamauga Lake.” Each PDF contained multiple pages of maps that split up bathymetric data for different sections of the river. Each page was georeferenced using the software ERDAS Imagine. Georeferenced maps were imported into ArcGIS Pro and contour lines were traced as point shapefiles with stored depth data. A polygon of the Tennessee River was created covering the extent of the point depth data to be used as a mask for geoprocessing. Depth point data were converted to raster through the Topo to Raster spatial interpolation tool for burning into the DEM. The Raster Calculator tool was then used to stitch the DEMs together. The resulting raster seamlessly combines the Tennessee River bathymetry data with the original USGS DEM and can be used for hydrodynamic modeling

Comparison Between Topographic Expression of RADARSAT and DEM in Simpang Pulai to Pos Selim, Malaysia

Radar and digital elevation model had been utilised in many structural studies. The main objective of this study is to compare the RADARSAT and digital elevation model for lineament interpretation which probably represent the main joints or faults along the Simpang Pulai to Pos Selim highway, Malaysia. These joints and faults may influence the instability along the highway. Manual comparison in terms of topographical aspect was undertaken between RADARSAT with 25 m spatial resolution and digital elevation model derived from 20 m contour interval of the topographical map. The previously interpreted lineaments of more than 2 km in the study area was draped over the RADARSAT and digital elevation model to compared whether the lineament concurred with the topographical representation. The interpreted lineaments were derived from Landsat TM of 1990 and 2002, where the DEM had been utilised in the negative lineament determination. It is concluded that the application RADARSAT is not very useful in terms of topographical expression in the structural geological interpretation for the study area compared to DEM derived from contour data. Further work is suggested before any conclusion can be confidently derived