Application of digitalelevation and geological data in studies of morphotectonics and relief - a case study of the sub-Cambrian peneplain in south-western Sweden
Cambrian ; Geographical information system ; Numerical model ; Palaeogeography ; Palaeogeomorphology ; Peneplain ; Sweden ; Tectonics
This paper aims to apply high resolution digitalelevation and geological data, as well as GIS and geostatistics, in order to describe the fragmentation and the gross morphological features of a restricted part of the sub-Cambrian peneplain
Surface elevation change and high resolution surface velocities for advancing outlets of Jostedalsbreen
Aerial photography ; Digitalelevationmodel ; Geographical information system ; Glacier ; Glacier advance ; Glacier dynamics ; Norway ; Photogrammetry
Avancée du glacier ; Dynamique glaciaire ; Glacier ; Modèle numérique de terrain ; Norvège ; Photogrammétrie ; Photographie aérienne ; Système d'information géographique
Velocity fields for the 3 outlet glaciers Nigardsbreen, Bergsetbreen and Baklibreen of Jostedalsbreen, southern Norway, have been obtained from successive orthophotos by digital image processing. The orthophotos were generated with standard digital
Automated mapping of land components from digitalelevation data
Algorithme ; Cartographie automatique ; Géomorphologie ; Modèle numérique ; Nouvelle-Zélande ; Utilisation du sol ; Versant
Algorithm ; Automated mapping ; Geomorphology ; Land use ; New Zealand ; Numerical model ; Slope
An algorithm for automating the mapping of land components from digitalelevation data is described. Aspect regions, which generally span from stream to ridge, are first identifed by generalizing an aspect map derived from digitalelevation data
. The aspect regions are then split successively into land components by grouping pixels above or below an automatically determined contour of elevation or distance from stream. The contour approximates a slope break. The land components mapped in this way give
The concept of a geomorphological signature is developed for classifying and mapping slope units with an automated procedure for analysing digitalelevation and remote sensing data. Slope units are extracted from a digitalelevationmodel (DEM
Slope and aspects calculations on gridded digitalelevationmodels : examples from a geomorphometric toolbox for personal computers
Algorithme ; Etats-Unis ; Géomorphométrie ; Modèle numérique ; Mount St. Helens ; New York State ; Pente de versant ; Versant ; Washington ; West Point
Algorithm ; Geomorphometry ; New York State ; Numerical model ; Slope ; Slope gradient ; United States of America ; Washington
This paper discusses some results from analyses of slope and aspects computed with a geomorphometric program, MICRODEM. The results discussed here primarily deal with 2 digitalelevationmodels (DEMs) produced by the U.S. Geological Survey, although
with NE-SW trending ridges. Slope and aspects calculations from DEMs reflect the underlying terrain, the digitization process, and the chosen algorithm.
Geomorphometric measures for digitalelevationmodels
Algorithme ; Bassin-versant ; Bilan hydrologique ; Eau de fonte ; Géomorphométrie ; Honshū ; Japon ; Modèle numérique ; Ruissellement ; Réseau de drainage ; Traitement des données
Algorithm ; Data processing ; Drainage network ; Geomorphometry ; Honshu ; Japan ; Meltwater ; Numerical model ; Rill wash ; Water balance ; Watershed
Geomorphometric measures developed for contour maps are redefined here specifically for digitalelevationmodels (DEMs). The measures are of 3 types depending on the feature localized : point, window, or drainage basin - the principal focus
of this paper. A new algorithm for gridding digitized contours, based on a convergent calculation using the harmonic mean. Finally, a new processing algorithm of the flooding type is introduced for drainage-basin geomorphometry on DEMs. It fills spurious
Alberta ; Canada ; Chenal anastomosé ; Cours d'eau ; Dynamique fluviale ; Ecoulement fluvial ; Géométrie hydraulique ; Modèle numérique de terrain ; Photogrammétrie ; Rocky Mountains ; Rugosité ; Transport sédimentaire
Imagery acquired using a high-resolution digital camera and ground survey has been used to monitor changes in bed topography and plan form, and to obtain synoptic water-surface and flow-depth information in the braided, gravel-bed Sunwapta River
in the Canadian Rockies. Digital images were obtained during daily low flows during the summer meltwater season to maximize the exposed bed area and to map the water surface on the days with the highest flows. The good results allow the AA. to identify other
Arid area ; Australia ; Flood ; Geochemistry ; Model ; Northern Territory ; Remote sensing ; Sediment transport ; Watershed
at catchment scale. Survey elevation data are combined with contour data to produce digitalelevationmodels for terrain analysis, tracing of sediment flow paths and modelling of extreme floods. The resultant patterns are compared with observed radioelement
This paper proposes a technique, residual relief separation, to enhance landforms in DEMs prior to visualization and digital mapping. This is applied to a 600km2 region surrounding Lough Gara, Ireland, where drumlins overlie a regional relief
Mapping contemporary magnetic mineral concentrations in peat soils using fine-resolution digital terrain data
Cartography ; Digitalelevationmodel ; England ; Gully erosion ; Hydromorphic soil ; Magnetic susceptibility ; Peat bog ; Soil properties ; Topography ; United Kingdom ; Yorkshire
Cartographie ; England ; Modèle numérique de terrain ; Propriétés du sol ; Ravinement ; Royaume-Uni ; Sol hydromorphe ; Susceptibilité magnétique ; Topographie ; Tourbière ; Yorkshire
Recent adavances in the field od digital terrain analysis and the avaibility of fine-resolution digitalelevationmodels means that the relationship between the concentration of magnetic minerals in peat soils and topography can be explored using
The effects of the topographic data source and resolution on the hydraulic modelling of floods were analysed. Seven digital terrain models (DTMs) were generated from three different altimetric sources : a global positioning system (GPS) survey
and bathymetry; high-resolution laser altimetry data LiDAR (light detection and ranging); and vectorial cartography (1:5000). Selection criteria were established for the different topographic models in order to assess their generation and treatment in relation
to the time-cost ratio for each methodology. the hydraulic modelling was carried out on a 2 km reach of the Ted River near Sant Juliá de Ramis near Girona in NE Spain.
Alabama ; Drainage network ; Hydrology ; Model ; Numerical model ; Slope ; Slope gradient ; United States of America ; Watershed
Four scaling regimes are observed in DigitalElevationModels (DEMs) when the average local slope is calculated for pixels grouped according to the values of the contributing area. Threshold criteria, proposed by various researchers to identify
the extent of the channel network, are examined relative to the slope-area scaling diagram. The AA. are especially interested in examining the relationship between the threshold response of erosion resistance used by Willgoose et al. (1991a) in their model
Aerial photography ; Forest ; Gully erosion ; New Zealand ; North Island ; Numerical model ; Photogrammetry ; Reforestation ; Sediment load ; Watershed
In this paper, area and elevation differences derived from high-resolution digitalelevationmodels (DEMs) are used to estimate the amount of sediment contributed by gully erosion. tHE AA. describe the methodology and errors involved in determining
Canada ; Chenal anastomosé ; Cours d'eau ; Erosion des berges ; Modèle numérique de terrain ; Méthodologie ; Photogrammétrie ; Saskatchewan ; Traitement des données ; Télédétection
determination of detailed depth maps for inundated areas and, when combined with dry area data, creation of complete digitalelevationmodels. Error propagation methods were used to determine the erosion and deposition depths detectable from sequential digital
photogrammetry was used to quantify dry areas and water edge elevations. A methodology was then used to calibrate the spectral signature of inundated areas by combining established two media digital photogrammetric methods and image matching. This allowed
elevationmodels.
The AA. couple archival photogrammetric techniques with image processing methods and test these for quantification of sand-bed braided river dynamics, illustrated for a 500 m wide, 3 km long reach of the South Saskatchewan River, Canada. Digital
Spectral filtering as a method of visualising and removing striped artefacts in digitalelevation data
Comparative study ; Digitalelevationmodel ; England ; Error ; Geographical information system ; Geomorphometry ; Norway ; Research technique ; United Kingdom
England ; Erreur ; Etude comparée ; Géomorphométrie ; Modèle numérique de terrain ; Norvège ; Royaume-Uni ; Système d'information géographique ; Technique de recherche
Spectral filtering was compared with traditional mean spatial filters to assess their ability to identify and remove striped artefacts in digitalelevation data. The techniques were applied to 2 datasets : a 100 m contour derived digitalelevation
. Artefacts were found to be heterogeneous through the surfaces, a result of their strong correlations with spatially autocorrelated variables : landcover and landsurface geometry. Spectrally filtered digitalelevation datasets were found to provide a superior
model (DEM) of southern Norway and a 2m LiDAR DSM of the Lake District, UK. Both datasets contained diagonal data artefacts. Spectral filtering used fast Fourier transformation (FFT) frequency data to identify these data artefacts in both datasets
Extraction of coastal terraces and shoreline-angle elevations from digital terrain models, Santa Cruz and Anacapa Islands, California
California ; Cartography ; Coastal environment ; Digitalelevationmodel ; Geographical information system ; Island ; Tectonics ; Terrace ; United States of America
California ; Cartographie ; Etats-Unis ; Ile ; Littoral ; Modèle numérique de terrain ; Système d'information géographique ; Tectonique ; Terrasse
, and elevation of coastal terraces, and then demonstrate how the results can be used to describe patterns of tectonic deformation. The technique could also be applied to other problems involving coastal terraces, or to studies involving other similarly shaped
Improving digitalelevationmodel of antarctica using radar remote sensing data and GIS techniques
Antarctique ; Glaciologie ; Image satellite ; Modèle numérique de terrain ; Système d'information géographique ; Topographie ; Traitement des données ; Télédétection
Discussion de différentes améliorations apportées au modèle numérique de terrain de l'Antarctique publié par l'A. en 1999. Les AA. montrent aussi comment les données radar et les systèmes d'information géographique peuvent être utilisés pour
Identifying large-scale erosion and deposition proceses from airborne gamma radiometrics and digitalelevationmodels in a weathered landscape
Australie ; Bassin-versant ; Erosion des sols ; Géophysique ; Modèle ; Modèle numérique de terrain ; Météorisation ; New South Wales ; Rayon gamma ; Télédétection
Australia ; Geophysics ; Model ; New South Wales ; Remote sensing ; Soil erosion ; Watershed ; Weathering
patterns associated with erosion and deposition is described and applied to gamma ray data from small drainage basins in southeastern Australia. A short review of digitalelevationmodel (DEM) generation from geophysical survey data is also presented since
Evaluation on the accuracy of digitalelevationmodels
Chine ; Concept ; Erreur ; Modèle ; Modèle numérique de terrain ; Méthode des moindres carrés ; Méthodologie ; Rugosité ; Système d'information géographique
China ; Concept ; Error ; Geographical information system ; Least squares method ; Methodology ; Model ; Roughness
There is a growing interest in investigating the accuracy of digitalelevationmodel (DEM). However people usually emphasize DEM sampling errors, but ignore the impact of DEM resolution and terrain roughness on the accuracy of terrain representation