Imagery & Data Digital Elevation Models (DEMs)
Digital Elevation Models
A Digital Elevation Model (DEM) is a digital representation of ground surface topography or terrain. A DEM can be represented as a raster (a grid of squares) or as a triangular irregular network. DEMs are commonly built using remote sensing techniques; however, they may also be built from land surveying. DEMs are often used in geographic information systems and serve as the most common basis for digital relief maps and are commonly called Digital Surface Models (DSMs).
View Intermap NEXTMAP brochure (pdf)
Now Available: TerrainNow - www.TerrainNow.com
Intermap Technologies NEXTMap high-resolution countrywide elevation data is now available for online purchase on www.TerrainNow.com, an offshoot portal of Spatial on Demand ®, and on Spatial on Demand - the world's largest energy-specific online database- for current subscribers to discover for download and purchase through their existing subscription and portal.
- Instantly discover, purchase and download Digital Surface and Digital Terrain Models directly online
- Coming late 2011
- European and Global Data Sets available for clip, zip and ship from terrainnow.com
- Orthorectified Radar Image (ORI) available for clip, zip and ship from terrainnow.com
- Accuterra Layers WMS available as a subscription
Intermap Technologies®' NEXTMap® Elevation Data (DEMs)
Spatial Energy partners with industry-leading companies, like Intermap Technologies, to meet the needs of energy companies worldwide. Intermap is a digital mapping company that has set the industry standard for highly reliable 3D digital models (DEMs) of the earth’s surface, including digital elevation data and geometric images of unprecedented uniform accuracy.
Intermap has built national databases, called NEXTMap and Spatial Energy provides these DEMs to our customers. In addition to NEXTMap USA, NEXTMap Europe and NEXTMap Britain, a host of additional digital elevation datasets (DEMs) are available, including Indonesia, Jamaica, the Philippines, Puerto Rico, the Solomon Islands, and Vanuatu.
NEXTMap datasets are current, off-the-shelf products that can be purchased immediately and are available in different specifications and types. Verified by eleven, national independent agencies, these models provide a high degree of accuracy and have many applications within the energy industry.
This NEXTMap DSM shows an area in the Marcellus Basin where the data is being used to eliminate unnecessary, counterproductive guesswork and optimize investments in natural oil and gas exploration and production.
Available Products Include:
- Digital Terrain Models
- Digital Surface Models
- Orthorectified Radar Images
- Coverage: Varies
- Vintage: Archive
- Buy Now: DEM Online Data Store - coming soon!
- Pricing and Area of Interest: Email to firstname.lastname@example.org
Common uses of DEMs include:
- new venture planning
- modeling surface and ground water flow patterns
- view shed/line of sight analysis
- logistics planning
- seismic planning
- well site planning
- pipeline route planning
- facility planning
- drainage analysis
- cut-fill operations
- creation of relief maps
- extraction of terrain parameters
- rendering of 3D visualizations
- rectification of aerial photography or satellite imagery
Quality of DEMs
The quality of a DEM is a measure of how accurate elevation is at each pixel (absolute accuracy) and how accurately is the morphology presented (relative accuracy). Several factors play an important role for quality of DEM-derived products:
- terrain roughness
- sampling density (elevation data collection method)
- grid resolution or pixel size
- interpolation algorithm
- vertical resolution
- terrain analysis algorithm
ASTER GDEM was produced using ASTER data acquired from the start of observation to the end of August, 2008 in cooperation with the Japan-US ASTER Science Team.
ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is an imaging instrument flying on Terra, a satellite launched in December 1999 as part of NASA's Earth Observing System (EOS). ASTER is a cooperative effort between NASA, Japan's Ministry of Economy, Trade and Industry (METI) and Japan's Earth Remote Sensing Data Analysis Center (ERSDAC). ASTER is being used to obtain detailed maps of land surface temperature, reflectance and elevation.
ASTER GDEM is now released and its distribution started, after the validation and the distribution site design.
Spatial Energy Offers DSM and DTM Products:
In addition to DEMs, Spatial Energy can also provide either digital surface models (DSMs) or digital terrain models (DTMs) when digital representations of the earth with buildings and vegetation removed are needed.
Spatial Energy Offers the Following DSM Products:
Spatial 1m Digital Surface Model (DSM)
This digital surface model represents the terrain elevations and surface elevation of tree canopy and the top of buildings. Break lines are not added to the DSM. Bodies of water are flattened. The post spacing is 5 meters with vertical accuracy in open flat terrain of f 1m (RMSE).
Spatial 7m Digital Surface Model (DSM)
This digital surface model represents terrain elevations and also represents the surface elevation of tree canopy and the top of buildings. Larger objects are edited to the ground except in areas of dense canopy where the ground height cannot be determined. No break lines added to the DSM. Bodies of water are flattened. The post spacing is 30 meters with vertical accuracy in open flat terrain of 7m (RMSE).
Digital Terrain Model (DTM)
A Digital Terrain or “Bare Earth” Model can also be created when there is a requirement for a digital representation of the earth void of all buildings and vegetation. Pricing for DTMs can be provided on a custom project basis.
information and pricing, please
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