نتایج جستجو برای: digitial elevation model dem

تعداد نتایج: 2176518  

Journal: :Trans. GIS 2004
Stefan Kienzle

It is well known that the grid cell size of a raster digital elevation model has significant effects on derived terrain variables such as slope, aspect, plan and profile curvature or the wetness index. In this paper the quality of DEMs derived from the interpolation of photogrammetrically derived elevation points in Alberta, Canada, is tested. DEMs with grid cell sizes ranging from 100 to 5 m w...

2012
Katherine Arrell Steve Wise Jo Wood Danny Donoghue

Spectral filtering was compared with traditional mean spatial filters to assess their ability to identify and remove striped artefacts in digital elevation data. The techniques were applied to two datasets: a 100 m contour derived digital elevation model (DEM) of southern Norway and a 2 m LiDAR DSM of the Lake District, UK. Both datasets contained diagonal data artefacts that were found to prop...

2015
Katherine Arrell Steve Wise Danny Donoghue

Spectral filtering was compared with traditional mean spatial filters to assess their ability to identify and remove striped artefacts in digital elevation data. The techniques were applied to two datasets: a 100 m contour derived digital elevation model (DEM) of southern Norway and a 2 m LiDAR DSM of the Lake District, UK. Both datasets contained diagonal data artefacts that were found to prop...

1999
R. Guritz M. Ayers T. Logan S. Li O. Lawlor

The Alaska SAR Facility has developed an automated procedure for production of a digital elevation model (DEM) from ESA tandem mission data. This software processes from ASF Computer Compatible Signal Data (CCSD) or Level Zero (raw) products to a map-projected, ground-range 30m DEM. Several advanced techniques have been integrated into the procedures to improve accuracy and to allow full automa...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2007
QinKe Yang Tim R. McVicar Tom G. Van Niel Michael F. Hutchinson LingTao Li Xiaoping Zhang

A hydrologically correct digital elevation model (DEM) forms a basis for realistic environmental modelling, especially in complex terrain. We have performed a study in the Coarse Sandy Hilly Catchments (CSHC) of the Loess Plateau, China, which demonstrates pragmatic, yet effective methods for improving the quality of the DEM by: (1) identifying and correcting source topographic data errors and ...

2004
D. Skarlatos A. Georgopoulos

The need for Digital Elevation Model (DEM) checking has raised since the automated matching techniques emerged. The use of reference data is a luxury and therefore cannot be used in all cases. This article presents a completely new mathematical model, which translates discrepancies between two orthophotographs created from different photographs, into precise corrections of the DEM. These correc...

2012
Hai Li Renbiao Wu

Synthetic aperture radar interferometry (InSAR) is an important remote sensing technique to retrieve the terrain digital elevation model (DEM)[1][2]. Image coregistration, InSAR interferometric phase estimation (or noise filtering) and interferometric phase unwrapping[3][4][5][6] are three key processing procedures of InSAR. It is well known that the performance of interferometric phase estimat...

Journal: :Computers & Geosciences 2007
R. Jana T. V. Reshmidevi P. S. Arun T. I. Eldho

A digital elevation model (DEM) of a watershed can be used to acquire various parameters such as basin-wide information about overland flow direction, flow accumulation and area contributing flow to any point. The resolution and quality of a DEM are important to achieve a significant level of accuracy in derived parameters. Inadequate elevation information exacerbated by applied interpolation m...

Journal: :Environmental Modelling and Software 2007
Simon Wu Jonathan Li Guo H. Huang

The spatial uncertainty of a topography based rainfall runoff model (TOPMODEL) is addressed in this study to assess its variability in simulating watershed hydrologic response with regards to the change of digital elevation model (DEM) resolution. Twelve DEM realizations of different grid sizes ranging from 30 m to 3000 m for each of two case watersheds are used for comparative examinations. Th...

Journal: :J. Geographic Information System 2011
B. S. Jacoby E. W. Peterson T. Dogwiler

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...

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