Algorithms are presented which use a digital elevation model (DEM) to extract topographic patterns. The algorithms have been applied to extracting natural topographic automatically from the regular grid DEM of a testing area. The experimental results have proved that the automatic extracting algorithms are effective.

Nowadays there is a wide range of systems that provide an efficient and fast data capture for the DEM generation and the spread of the computer systems has allowed the use of DEM to a high number of technicians. Unfortunately, the DEM analysis tools do not have similar development. Actually, the analyses are mainly based in the application of local scale operators that provide additional inform...

High-altitude Himalayan terrain exhibits extreme geometric distortion along north-facing (dilation) and south-facing (compression) slopes as observed in satellite stereo data with high look angles. In the present study, Cartosat-1 stereo pairs have been used for generating Digital Elevation Model (DEM) using Differential Global Positioning System based Ground Control Points. DEM quality assessm...

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...

Terrain modeling is a fast growing field with many applications such as computer graphics, resource management, Earth and environmental sciences, civil and military engineering, surveying and photogrammetry and games programming. One of the most widely used terrain model is the Digital Elevation Model (DEM). A DEM is a simple regularly spaced grid of elevation points that represent the continuo...

Cave levels, passages found at similar elevations and formed during the same constant stream base level event, reveal information about paleoclimates and karst geomorphology. The investigation presented here examines how Stream Power Index (SPI) relates to cave levels. The study area, Carter Caves State Resort Park (CCSRP), is a fluviokarst system in northeastern Kentucky containing multiple ca...

There are many kinds of DEM (Digital Elevation Model) generation methods such as a stereomatching from aerial photograph or satellite image, an interferometry from SAR data and an interpolation of topographic maps. On the other hand, we can use some accomplished DEMs. For example, NGDC NOAA offers global land one-km base elevation (GLOBE). And USGS offers Digital Chart of the World that has ele...

DEM(Digital Elevation Model)-based digital differential rectification is a very popular method for producing Digital Orthophoto Model(DOM) out of central perspective imagery. However, it is by not the unique way. Three other non-DEM methods are proposed and discussed technically in the paper. (1) If central perspective-sensed images are in the form of stereopair, then parallax can be computed b...

Partial randomization dynamic element matching (DEM) was recently introduced as a promising DEM technique for low harmonic distortion digital-to-analog conversion. The DEM technique is well suited for applications such as direct digital synthesis in wireless communication systems for which low hardware complexity is essential in addition to low harmonic distortion. Previously reported simulatio...

Users of GIS are faced with the ongoing and difficult problem of estimating the validity of a GIS output given the uncertainty of the quality of cLgital mapped data. This research project examines the manner in which error from a digital elevation model (DEM) results in error in an estimate of a viewshed. The data set includes two DEMs for the same study area. A 10-metre DEM serves as the contr...