Digital Terrain Model DTM - Instantly export ASC, DXF, XYZ, DWG: FINDmaps.co.uk
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Digital Terrain Model


The Digital Terrain Model (DTM) is a representation of the ground surface after the vegetation and built structures have been digitally removed. You can download the regular grid of points containing elevation values allowing the terrain of an area to be viewed in 3D. This is particularly useful during the planning and design stages of a development when terrain characteristics can be included in site analysis and incorporated into proposed schemes. It can also be used when carrying out environmental assessments where profiles and cross sections are required, such as in flood modelling.

The usefulness of a DTM is directly dependent on the grid interval and the data source it is generated from. FIND provides data collected by LiDAR (Light Detection and Ranging), RADAR (Radio Detection and Ranging) and photogrammetry methods:

  • LiDAR

This is a method of collecting elevation information from the air where a high degree of vertical accuracy is required. The the Blom DTM with 50cm grid spacing is produced using this method.

  • RADAR

This is also an airborne method of collecting information, using radio waves instead of light waves. RADAR is generally considered a less accurate method of collecting elevation information but it is suitable for more generalised studies of landscape where high detail accuracy is less important and cost is a consideration. The NEXTMap 5m DTM data available on FIND was produced using this method.

  • Photogrammetry

This is a method of deriving elevation information from high-resolution aerial photographs. For practical comparison, photogrammetry derived height data is within a few centimetres of LiDAR in open areas but is actually better than LiDAR when it comes to building heights. The Getmapping DTM with 5m grid spacing available on FIND was produced using this method.

Coverage areaLiDAR Sporadic throughout Britain (RADAR full coverage)
ExportableYes (not printable or viewable)
Export formatsDWG, DXF, XYZ, ASC

Data providerBlom Aerofilms
Vertical accuracy of data+/- 15cm
Horizontal accuracy of data+/- 100cm (1m)
Version date of datasetAugust 2007
Frequency of update cycleNo update planned
Maximum export size via internet50 hectares (0.5 km²)

Data providerIntermap NEXTMap
Vertical accuracy of data+/- 100cm (1m)
Horizontal accuracy of data+/- 250 cm (2.5m) on slopes less than 20 degrees
Version date of dataset2002-2004
Frequency of update cycleNo update planned
Maximum export size via internet300 hectares (3 km²)

Data providerGetmapping
Vertical accuracy of data+/- 100cm (1m)
Horizontal accuracy of data+/- 40 cm
Version date of dataset2005-2009
Frequency of update cycleRegular updates
Maximum export size via internetUnlimited (order delivered offline)

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