OVERVIEW
The NEXTMap topographic data was collected using Intermap’s Star-3i IFSAR (Interferometric Synthetic Aperture Radar) producing a Digital Surface Model (DSM), a Digital Terrain Model (DTM) and orthorectified radar imagery (ORI) for the whole of the England, Scotland and Wales. Intermap and Geosense have produced a wide variety of products which are ready to buy off-the-shelf from Geosense in a wide variety of GISand CAD ready formats.
Remotely sensed imagery, such as satellite data, with known solar elevation and azimuth are combined with the NEXTMap terrain models to remove the variation in image brightness caused by topographic effects. This process is known as topographic normalisation. Geosense as a reseller of all commercial satellite data can use the NEXTMap models to remove these topographic effects.
Contact Geosense for prices on all NEXTMap Britain and Other NEXTMap datasets from around the world including USA and Indonesia.
The NEXTMAp Orthorectified Radar Image (ORI) is a greyscale image formed from the return of the radar pulse. The image produced is a representation of surface texture and as the radar looks at a angle can give more indication of height of features than is possible with aerial photography.
The NEXTMap ORI is at 1.25m resolution and available from Geosense in geotiff, jpg, ecw and MrSid format.
NEXTMap Digital Terrain Model is available with postings at 5m, 10m and 50m intervals. The DTM is devoid of vegetation, buildings and other features, leaving a bald earth model.
Formats avaialble form Geosense include ArcGrid, ASCII, DXF, NTF, DGN and DWG.
The NEXTMap Digital Surface Model contain heights of man-made structures and vegetation at postings every 5m. These heights are derived from the first surface the radar signals strike and are a representation of any object large enough to be resolved.
Formats available from Geosense include ArcGrid, ASCII, DXF, NTF, DGN and DWG.
The difference in height between the DSM and DTM shows the non-terrain features such as tree canopy and building heights. Formats from Geosense include ArcGrid, ASCII, dxf, DGN and DWG.
Geosense has generated cartographic contours at 5m intervals from the NEXTMap Britain DTM5 for the whole of the UK. These highly accurate contours are supplied with spotheights at regular intervals, and are a more detailed alternative to existing national datasets.
The NEXTMap Contours are aimed at those users who prefer to use contours instead of a regular gridded DTM, or for those working in 2D who require contours to represent slope and aspect on drawings and maps.
Formats available from Geosense include DXF, NTF, DGN and DWG.
Geosense have devised semi-automatic routines to enhance the NEXTMap Britain product by using photogrammetrically derived heights of buildings from Getmapping stereo aerial photography. The building models are accurate up to 50cm and are either embedded into the NEXTMap terrain models or as 3D outlines to be placed on top. Formats include 3D shapefiles and dxf.
Geosense NEXTMap Britain shaded relief of the UK is an invaluable tool, especially in education, for showing how the land has been sculptured by rivers and glaciers. This dataset can be merged in with other imagery such as satellite data to give a better indication of height. Formats include geotiff, jpg, ecw and MrSId.
Slope maps derived from the NEXTMap Britain DTM show the change in height or elevation over a distance, and are essential for road planning, slope stability and are used to identify wildlife habitats or classify vegetation species that are terrain-sensitive.
