Analysis Of Digital Elevation Models Research Articles

Rapid volume loss from two East Greenland outlet glaciers quantified using repeat stereo satellite imagery

The coastal portions of Kangerdlugssuaq and Helheim glaciers in southeast Greenland lost at least 51 ± 8 km3 yr−1 of ice between 2001–2006 due to thinning and retreat, according to an analysis of sequential digital elevation models (DEMs) derived from stereo ASTER satellite imagery. The dominant contribution to this ice loss was dynamic thinning caused by the acceleration in flow of both glaciers. Peak rates of change, including thinning rates of ∼90 m yr−1, coincided with the rapid increases in flow speed. Extrapolation of the measured data to the ice divides yields an estimated combined catchment volume loss of ∼122 ± 30 km3 yr−1, which accounts for half the total mass loss from the ice sheet reported in recent studies. These catchment‐wide volume losses contributed ∼0.31 ± 0.07 mm yr−1 to global sea level rise over the 5‐year observation period with the coastal regions alone contributing at least 0.1 ± 0.02 mm yr−1.

Higher Order Vagueness in a Dynamic Landscape: Multi-Resolution Morphometric Analysis of a Coastal Dunefield

Many environmental phenomena can be conceptualised as vague and so may be suitable for storage as fuzzy sets and analysis by fuzzy logic. Fuzzy sets directly address the vagueness in the information, but many consider that any statement about a vague phenomenon must itself be vague. This is known as higher order vagueness, and is handled in fuzzy set theory by type-2 and, by extension, type-n fuzzy sets. In this paper we use the recognition of, and change in, a system of coastal sand dunes as an environmental example in which to explore the use of type-2 fuzzy sets. The crests and troughs of the dunes are identified as fuzzy sets from geomorphometric analysis of high resolution digital elevation models from two years (1998 and 2000). By varying the parameters of the morphometric extraction, multiple instances of type-1 fuzzy sets can be defined, and these can be summarised to yield type-2 fuzzy sets. The logic of change analysis is presented, and two alternative approaches to change analysis of type-2 fuzzy sets implemented. In one approach changes in the multiple instances of type-1 fuzzy sets are analysed and summarised as type-2 sets. The second approach directly examines change in the parameters of type-2 fuzzy sets, viewing the results for the different parameters as separate instances of change. All analyses produce satisfactory results which, although they arc hard to verify, make sense, yielding a range of possible but small degrees of fuzzy change. In a rather sedentary dune system (as is usual in a coastal location in mid-latitudes) this is to be expected. Change analysis in most applications of type-2 fuzzy sets, which might be based on expert advice for defining memberships, would have to rely on this second approach, and it is therefore interesting to note that this yields the largest range of possible change results.

Bedrock landscape development modeling: Calibration using field study, geochronology, and digital elevation model analysis

Stream power–based models of bedrock landscape development are effective at producing synthetic topography with realistic fl uvial-network topology and three-dimensional topography, but they are diffi cult to calibrate. This paper examines ways in which fi eld observations, geochronology, and digital elevation model (DEM) data can be used to calibrate a bedrock landscape development model for a specifi c study site. We fi show how uplift rate, bedrock erodibility, and landslide threshold slope are related to steady-state relief, hypsometry, and drainage density for a wide range of synthetic topographies produced by a stream power–based planform landscape development model. Our results indicate that low uplift rates and high erodibility result in low-relief, high drainage density, fl uvially dominated topography, and high uplift rates and low erodibility leads to high-relief, low drainage density, mass wasting–dominated topography. Topography made up of a combination of flchannels and threshold slopes occurs for only a relatively narrow range of model parameters. Using measured values for hypsometric integral, drainage density, and relief, quantitative values of bedrock erodibility can be further constrained, particularly if uplift rates are independently known. We applied these techniques to three sedimentary rock units in the western Transverse Ranges in California that have experienced similar climate, uplift, and incision histories. The 10 Be surface exposure datincision of initially low-relief topography there occurred during the last ~60 k.y. We estimated the relative dependence of drainage area and channel slope on erosion rate in the stream power law from slope-area data, and inferred values for bedrock erodibility ranging from 0.09 to 0.3 m (0.2–0.4) k.y. –1 for the rock types in this study area.

EVENTOS TECTÔNICOS RECORRENTES IMPRESSOS NO ARCABOUÇO ESTRATIGRÁFICO DO GRUPO ITARARÉ NA REGIÃO DE VILA VELHA, ESTADO DO PARANÁ

O presente trabalho avalia o controle tectônico na deposição e deformação do intervalo basal doGrupo Itararé no sudeste do Estado do Paraná e sua influência na anisotropia de reservatórios análogos. Apartir da análise estrutural do arenito Vila Velha, a observação das relações espaciais entre a conformaçãodos estratos e as estruturas descritas e o mapeamento geológico de detalhe, propõe-se um modelo deevolução tectono-sedimentar para a área. O Grupo Itararé foi depositado em contexto glacial, glácio-marinhoe costeiro, tendo sido afetado por vários eventos tectônicos que influenciaram a sedimentação e deformarama seção sedimentar. A descrição do arcabouço estrutural/estratigráfico sugere uma história tectônica complexa,do Carbonífero ao Eocretáceo, com estruturas tectonicamente ativas durante a deposição e a suareativação em eventos tectônicos posteriores. A natureza da sedimentação e a deformação tectônicasuperimposta em múltiplos eventos imprimiram no arenito intensa anisotropia, com diferentes escalas deheterogeneidades estruturais e estratigráficas que limitam unidades de fluxo e controlam a circulação defluidos no meio poroso.

Sedimentation rates in relation to sedimentary processes of the Yangtze Estuary, China

Radioisotope analysis and Digital Elevation Model (DEM) method were combined to examine sedimentation rates and associated sedimentary processes in the Yangtze River Estuary. The major depocenter is validated at the delta front sedimentary facies above the normal wave base (NWB), where accumulation exceeds erosion. This alternated sedimentation does not accommodate Pb-210 and Cs-137 measurement, although sedimentation rates of less than 0.2–5.0 cm yr −1 were recorded in the fine-grained (silty) sediments, which were interbedded with coarse-grained (sandy) sediments. However, historical DEM data provide more detailed information on sedimentation in the delta front facies, where accumulation is dominant in the sandy shoals (1.73–8.30 cm yr −1) and delta front slope (5.22 cm yr −1) facies. The DEM data also show that erosion (1.61–7.32 cm yr −1) dominates in the northern estuarine distributaries, and accumulation (3.01–4.97 cm yr −1) prevails in the southern ones, primarily owing to the superimposed runoff and ebb tidal currents. Pb-210 and Cs-137 measurements reveal sedimentation rate from 2.0 cm yr −1 to 6.3–6.6 cm yr −1 in the delta front slope facies, which progressively decreases to <0.8 cm yr −1 in the prodelta facies and is unmeasurable in the delta-shelf transition zone. DEM analysis detects minor erosion in the delta front slope and prodelta facies, although accumulation predominates there. The present sedimentological database will be useful for estuarine environmental assessment after the Three-Gorges Dam is completed in 2009.

Long-term hydrodynamic response induced by past climatic and geomorphologic forcing: The case of the Paris basin, France

In the framework of safe underground storage of radioactive waste in low-permeability layers, it is essential to evaluate the mobility of deep groundwaters over timescales of several million years. On these timescales, the environmental evolution of a repository should depend upon a range of natural processes that are primarily driven by climate and geomorphologic variations. In this paper, the response of the Paris basin groundwater system to variations in its hydrodynamic boundary conditions induced by past climate and geodynamic changes over the last five million years is investigated. A three-dimensional transient modelling of the Paris basin aquifer/aquitard system was developed using the code NEWSAM (Ecole des Mines de Paris, ENSMP). The geometry and hydrodynamic parameters of the model originate from a basin model, NEWBAS (ENSMP), built to simulate the geological history of the basin. Geomorphologic evolution is deduced from digital elevation model analysis, which allows to estimate river-valley incision and alpine surrection. Climate forcing results from palaeoclimate modelling experiments using the LMDz atmospheric general circulation model (Institut Pierre Simon Laplace) with a refined spatial resolution, for the present, the Last Glacial Maximum (21 ka) and the Middle Pliocene Warmth (∼3 Ma). The water balance is computed by the distributed hydrological model MODSUR (ENSMP). Results about the simulated evolution of piezometric heads in the system in response to the altered boundary conditions are presented, in particular in the vicinity of ANDRA’s Bure potential repository site within the Callovo-Oxfordian argillaceous layer. For the present, the comparison of head patterns between steady state and time dependent simulation shows little differences for aquifer layers close to the surface but suggests a transient state of the current system in the main aquitards of the basin and in the deep aquifers, characterized by abnormally low fluid potentials. The dependence of the boundary-induced transient effects on the hydraulic diffusivity is illustrated by means of a sensitivity study.

A multidisciplinary approach to determine the structural geometry of hard-rock aquifers. Application to the Plancoet migmatitic aquifer (NE Brittany, W France)

Abstract A new multidisciplinary methodology is developed to determine the structural geometry of hard-rock aquifers. The Plancoët migmatitic basement, chosen as an example for the use of this methodology, is studied both at a regional (300 km2) and a local (4 km2) scale. The regional mapping, based on field mapping of the tectonic structures and the weathered layers, on geostatistics and on aerial photographs and Digital Elevation Model (DEM) analyses, demonstrates the influence of the tectonic structures on the weathering processes. Some geo-electric investigations, added to the first mapping at the local scale, lead to the building of a local geometrical model of the aquifer.

A Marked Point Process of Rectangles and Segments for Automatic Analysis of Digital Elevation Models

This work presents a framework for automatic feature extraction from images using stochastic geometry. Features in images are modeled as realizations of a spatial point process of geometrical shapes. This framework allows the incorporation of a priori knowledge on the spatial repartition of features. More specifically, we present a model based on the superposition of a process of segments and a process of rectangles. The former is dedicated to the detection of linear networks of discontinuities, while the latter aims at segmenting homogeneous areas. An energy is defined, favoring connections of segments, alignments of rectangles, as well as a relevant interaction between both types of objects. The estimation is performed by minimizing the energy using a simulated annealing algorithm. The proposed model is applied to the analysis of Digital Elevation Models (DEMs). These images are raster data representing the altimetry of a dense urban area. We present results on real data provided by the IGN (French National Geographic Institute) consisting in low quality DEMs of various types.

The late Quaternary stratigraphic record northwest of Montréal: regional ice-sheet dynamics, ice-stream activity, and early deglacial events

The Quaternary sediments of previously unstudied buried valleys and sections near Montréal are analyzed and other sites are revisited to further develop the stratigraphic framework of the St. Lawrence Lowland and to establish regional glacial and deglacial models. The southwest-trending buried valleys were investigated by stratigraphic drilling and high-resolution seismic profiling. The Quaternary succession consists, from base to top, of proximal glaciolacustrine sediments, two superposed till sheets (Argenteuil and Oka tills) of inferred Late Wisconsinan age, and Champlain Sea sediments. The glacial sediments of this sequence record an ice advance toward south (Argenteuil Till) followed by an abrupt ice-flow shift toward the southwest (Oka Till). Compositional and geomorphic data indicate that Oka Till is ubiquitous and is associated with a regional set of glacial landforms. The analysis of a regional digital elevation model in combination with published ice-flow indicators shows convergent flow patterns from the Ottawa–Montréal–Adirondack regions toward the Lake Ontario basin. Landforms produced by the inferred ice stream are locally crosscut by southward-trending ice-flow features. Hence southward flow in the upper St. Lawrence Valley seemingly took place in two distinct contexts: (1) during full glacial conditions, as ice margins stood at or near the late glacial maximum limits, and (2) during late deglaciation, as a post-ice stream reequilibration mechanism. Early deglacial events in the study area were also characterized by subglacial meltwater channelling and erosion along the valleys, subaquatic outwash deposition in glacial Lake Candona, and rapid infill of the valleys during the early stages of the ensuing Champlain Sea.

The application of lidar-derived digital elevation model analysis to geological mapping: an example from the Fundy Basin, Nova Scotia, Canada

High-resolution laser altimetry (lidar) is applied to geological problems such as bedrock and surficial mapping and the relationship to earth surface processes in the Fundy Basin of Nova Scotia. A "bald earth" lidar digital elevation model (DEM) is used in conjunction with field observations to map three flow units of the Jurassic North Mountain Basalt (NMB) based on contrasting terrain characteristics (slope, smoothness, and relief). The variable resistance of the flow units to erosion, documented by shatterbox experiments and down-core fracture density data, has a measurable control on incision by post-glacial consequent streams. In catchments where till cover is thick, greater surface runoff and weaker infiltration increase incision by as much as 43% for a given flow unit. Interpretation of field, petrologic, and digital topography data indicates previously unrecognized craters in the lower flow unit are the result of interaction between partially solidified lava and surface water or groundwater. Two new sets of surficial landforms have been identified that indicate ice was directed northwestward into the Bay of Fundy during the late stages of glaciation. Twice as many wave-cut terraces have been identified in the lidar DEM than previously mapped, and elevations have been extracted and compared with published values that are related to higher sea-levels at 12–14 ka. This paper demonstrates through a range of examples that the precision and enhanced resolution of lidar can improve our understanding of how landscapes form and evolve.

Urban texture analysis with image processing techniques: winds and dispersion

The focus is the analysis of urban Digital Elevation Models (DEMs) with image processing techniques. A brief review of existing methods to derive sky view factors, building energy consumption and space syntax shows how well established parameters that relate to airflow and dispersion (such as the height-to-width of urban canyons and the aerodynamic roughness length) can be calculated. Other measures of urban directionality and periodicity, inspired by traditional image processing, are also introduced, such as the Radon, Hough and Fourier transforms and the variance plot. Analyses of three case study sites in London, Toulouse and Berlin are compared, showing considerable variation in the chosen parameters. Results suggest that the DEM format is an extremely versatile tool to investigate the urban intermediate scale, allowing analyses that would be very difficult or impossible to carry out using traditional vectorial models.

Simultaneous Spline Approximation and Topographic Analysis for Lidar Elevation Data in Open-Source GIS

Application of a spline approximation method to computation and analysis of lidar-based digital elevation models is investigated to determine its accuracy and capability to create surfaces at different levels of detail. Quadtree segmentation that adapts to the spatial heterogeneity of data points makes the method feasible for large datasets. The results demonstrate the importance of smoothing for the surface accuracy and noise reduction. A tension parameter is effective for tuning the level of detail in the elevation surface. Simultaneous computation of topographic parameters is applied to extraction of sand dunes' features for assessment of dune migration and beach erosion.

Horizontal resolution and data density effects on remotely sensed LIDAR-based DEM

Terrain analysis of digital elevation models (DEM) has become an important technique to assess landscape and watershed scale hydrologic and pedologic processes and the spatial variability of soil and ecologic properties. Light detecting and ranging (LIDAR) elevation data sets provide the flexibility needed to produce multiple horizontal resolutions of DEM from the same data source. A series of 61 LIDAR tiles (100 ha) were collected from the North Carolina Flood Mapping Program covering the spatial extent of the Hofmann Forest in the Lower Coastal Plain of Eastern North Carolina. The LIDAR data set was reduced to 50%, 25%, 10%, 5%, and 1% of the original density. We created 5-, 10-, and 30-m DEM with 0.1 m vertical precision for each density level and used paired t-test to determine if the true mean of their differences were equal to zero. Differences indicated that for the 30-m DEM, LIDAR data sets could be reduced to 10% of their original data density without statistically altering the produced DEM. However, the 10-m DEM could only be reduced to 25% of the original data set before statistically altering the DEM. Data reduction was more limited for the 5-m DEM with possible reduction only to 50% of their original density without producing statistically different DEM. Our evaluation provides some indication as to the minimum required LIDAR data density to produce a DEM of a given horizontal resolution. However, evaluation of additional horizontal resolutions and additional density reduction is required to provide a clearer understanding of the effect of LIDAR data density.

The Lineage of the Line: Space Syntax Parameters from the Analysis of Urban DEMs

A number of shortcomings of space syntax—a well-known technique of urban analysis—were recently discussed in the scientific literature. They are mostly traceable to the reliance in space syntax on the ‘axial map’: a simplified line-of-sight description of the city, which is then analysed based on its topology. This paper explores how another type of urban representations—namely the urban digital elevation model (DEM), a raster map which stores building heights—could prove helpful in providing complementary information to space syntax. Although the use of DEMs is common in the geo-sciences, their application in urban studies is more recent and shows promise. This paper presents several analysis algorithms to derive urban lines of sight, viewsheds, travelling time maps, and simulations based on cellular automata. The relevance of the approach is discussed, suggesting that it could effectively complement traditional space syntax in the coming years.

Évolution géomorphologique de l'avant-pays du Sud-Ouest de la Nouvelle-Calédonie durant les derniers cycles glaciaires

We present the morphological analysis of a combined digital elevation model (DEM) obtained by merging data from terrestrial and coastal regions of southern New-Caledonia. Our aim is to describe the Quaternary morphotectonic evolution of the southwestern lagoon of New Caledonia, a region with a shallow average bathymetry (20 m), recently submerged in response to both tectonic and eustatic fluctuations. The marine DEM was obtained by interpolating 131 000 depth soundings from MOP–SHOM (‘Mission oceanographique du Pacifique’–‘Service hydrographique et oceanographique de la Marine’, France). We confirm that morphologies such as meandering channels and deeply incised canyons are the result of a sub-aerial fluviatile evolution during periods of low sea levels. The marine sedimentation in this region is very recent, probably corresponding to no more than two glacial–interglacial cycles. Geometrical relationships between submerged paleo-rivers and streams, including captures and incisions, strongly suggest that Quaternary active tectonics affected river development. We identify two hydrographic palaeo-networks suggesting outflow changes, from parallel to the present-day island axis to perpendicular. To cite this article: V. Chevillotte et al., C. R. Geoscience 337 (2005).

Digital close range photogrammetry for measurement of soil erosion

AbstractMany of the processes involved in soil erosion have dimensions on the millimetre scale. Modelling and quantification of such processes require information on soil surface topography with adequate resolution. The purpose of this study was to generate digital elevation models (DEMs) from soil surfaces with high spatial and temporal resolution. Digital photogrammetry was applied for measuring erosion rates on complex‐shaped soil surfaces under laboratory rainfall conditions. A total of 60 DEMs were generated, covering a planimetric area of 16 m2. The DEMs had a grid resolution of 3 mm. A vertical precision of approximately 1 mm was desired for DEM analysis. A consumer‐grade digital camera was used for image acquisition. The camera was calibrated using BLUH software. Homologous points in overlapping images were identified with least squares matching software. Irregularly spaced object coordinates were interpolated to a regular grid in a geographic information system. The resulting DEMs represented the soil surface well. A precision of 1·26 mm in the vertical was attained. The precision of DEM production was limited to camera calibration. Improvements of the setup presented could include the use of better control points and more advanced image matching strategies for identification of homologous points. The DEMs allowed for detailed analysis of soil surface evolution.

Energy consumption and urban texture

This paper explores the effects of urban texture on building energy consumption. It is based on the analysis of digital elevation models (DEMs)—raster models of cities which have proven to be very effective in the urban context. Different algorithms are proposed and discussed, including the calculation of the urban surface-to-volume ratio and the identification of all building areas that are within 6 m from a façade (passive areas). An established computer model to calculate energy consumption in buildings, the LT model, is coupled with the analysis of DEMs, providing energy simulations over extensive urban areas. Results for the three case study cities of London, Toulouse and Berlin are presented and discussed.

Removal of artifact depressions from digital elevation models: towards a minimum impact approach

Artifact depressions in digital elevation models (DEMs) interrupt flow paths and alter drainage directions. Techniques for removing depressions should enforce continuous flow paths in a way that requires the least modification of the DEM. Impacts on the spatial and statistical distributions of elevation and its derivatives were assessed for four methods of removing depressions: (1) filling; (2) breaching; (3) a combination of filling and breaching, with breaching constrained to a maximum of two grid cells; (4) a combination of filling and breaching based on an impact reduction approach (IRA). The IRA removes each depression using either filling or breaching, depending on which method has the least impact, in terms of the number of modified cells and the mean absolute difference in the DEM. Analysis of a LiDAR DEM of a landscape on the Canadian Shield showed significant differences in the impacts among the four depression removal methods. Depression filling, a removal method that is widely implemented in geographical information system software, was found to impact terrain attributes most severely. Constrained breaching, which relies heavily on filling for larger depressions, also performed poorly. Both depression breaching and the IRA impacted spatial and statistical distributions of terrain attributes less than depression filling and constrained breaching. The most sensitive landscapes to depression removal were those that contained large (i.e. >10%) flat areas, because of the occurrence of relatively large depressions in these areas. Copyright © 2005 John Wiley & Sons, Ltd.

DEM-based morphometry of range-front escarpments in Attica, central Greece, and its relation to fault slip rates

In this paper, we apply current geological knowledge on faulting processes to digital processing of Digital Elevation Models (DEM) in order to pinpoint locations of active faults. The analysis is based on semiautomatic interpretation of 20- and 60-m DEM and their products (slope, shaded relief). In Northern–Eastern Attica, five normal fault segments were recognized on the 20-m DEM. All faults strike WNW–ESE. The faults are from west to east: Thriassion (THFS), Fili (FIFS), Afidnai (AFFS), Avlon (AVFS), and Pendeli (PEFS) and range in length from 10 to 20 km. All of them show geomorphic evidence for recent activity such as prominent range-front escarpments, V-shaped valleys, triangular facets, and tilted footwall areas. However, escarpment morphometry and footwall geometry reveal systematic differences between the “external” segments (PEFS, THFS, and AVFS) and the “internal” segments (AFFS and FIFS), which may be due to mechanical interaction among segments and/or preexisting topography. In addition, transects across all five escarpments show mean scarp slope angles of 22.1°±0.7° for both carbonate and metamorphic bedrock. The slope angle equation for the external segments shows asymptotic behaviour with increasing height. We make an empirical suggestion that slope angle is a function of the long-term fault slip rate which ranges between 0.13 and 0.3 mm/yr. The identified faults may rupture up to magnitude 6.4–6.6 earthquakes. The analysis of the 60-m DEM shows a difference in fault patterns between Western and Northern Attica, which is related to crustal rheology variations.

Methods for Remote Engineering Geology Terrain Analysis in Boreal Forest Regions of Ontario, Canada

Research Article| March 01, 2004 Methods for Remote Engineering Geology Terrain Analysis in Boreal Forest Regions of Ontario, Canada PETER J. BARNETT; PETER J. BARNETT 1Ontario Geological Survey, Ministry of Northern Development and Mines, 933 Ramsey Lake Road, Sudbury, ON P3E 4V6 Search for other works by this author on: GSW Google Scholar VERNON H. SINGHROY; VERNON H. SINGHROY 2Canada Centre for Remote Sensing, Natural Resources Canada, 588 Booth Street, Ottawa, ON K1A 0Y7 Search for other works by this author on: GSW Google Scholar JIRO SHIROTA; JIRO SHIROTA 3Ontario Geological Survey, Ministry of Northern Development and Mines, 933 Ramsey Lake Road, Sudbury, ON P3E 4V6 Search for other works by this author on: GSW Google Scholar STEPHEN J. LENEY STEPHEN J. LENEY 4Geomatic Service Centre, Ontario Ministry of Natural Resources, 300 Water Street, Peterborough, ON K9J8M5 Search for other works by this author on: GSW Google Scholar Author and Article Information PETER J. BARNETT 1Ontario Geological Survey, Ministry of Northern Development and Mines, 933 Ramsey Lake Road, Sudbury, ON P3E 4V6 VERNON H. SINGHROY 2Canada Centre for Remote Sensing, Natural Resources Canada, 588 Booth Street, Ottawa, ON K1A 0Y7 JIRO SHIROTA 3Ontario Geological Survey, Ministry of Northern Development and Mines, 933 Ramsey Lake Road, Sudbury, ON P3E 4V6 STEPHEN J. LENEY 4Geomatic Service Centre, Ontario Ministry of Natural Resources, 300 Water Street, Peterborough, ON K9J8M5 Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 Copyright © 2004 Geological Society of America Environmental & Engineering Geoscience (2004) 10 (3): 229–241. https://doi.org/10.2113/10.3.229 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation PETER J. BARNETT, VERNON H. SINGHROY, JIRO SHIROTA, STEPHEN J. LENEY; Methods for Remote Engineering Geology Terrain Analysis in Boreal Forest Regions of Ontario, Canada. Environmental & Engineering Geoscience 2004;; 10 (3): 229–241. doi: https://doi.org/10.2113/10.3.229 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract The Ontario Geological Survey and Canada Centre for Remote Sensing have developed methods for engineering geology terrain analysis using digital elevation models (DEMs) and remotely sensed imagery for remote areas within the boreal forest region of the Canadian Shield. Traditional methods of terrain analysis would be expensive because of the limited access and the vast area involved. Four main components of the terrain are considered: material, landform, relief, and regional drainage conditions. Landform (roughness) and relief are derived automatically from an analysis of a detailed hydrological-conditioned DEM. Regional drainage conditions are estimated from RADARSAT imagery with a mask based on the use of aspect and slope to limit the effects of topography on backscatter. Various types of analysis of LANDSAT imagery are then combined with all the above digital data layers to interpret material type. An automated method that first determines the relationships of the various layers of digital information in areas of known terrain conditions and then predicts terrain conditions in adjacent unmapped areas, is discussed. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.