NEXTMap Britain digital terrain model dataset, produced by Intermap, was derived from airborne Interferometric Synthetic Aperture Radar (IFSAR). It enabled large areas of the country to be covered rapidly and at very high spatial resolution. The data were acquired by the British Geological Survey (BGS) and are for use by NERC funded researchers only.

It was originally commissioned by Norwich Union Insurance to aid in the estimation of flood risk, but has tremendous potential as a scientific research tool.

The dataset covers all of England, Wales and Scotland.

Data are arranged into Ordnance Survey / British National Grid tiles of 10 x 10 km, each denoted by a 4-charcter name, e.g. TL63 based on the OS National Grid coordinates of the southwest corner of the square. Products provided include:

Digital surface mode (dsm)
Digital terrain model (dtm)
Difference model (dsm - dtm)
Digital terrain model at 10m resolution
Digital terrain model at 50m resolution
Digital terrain model, enhanced (manually edited to remove embankments etc.)
Orthorectified radar image (ori)

The data covering Northern Scotland (North of the Midland Valley) are only available as diff, dsm, dtm and ori products.

This dataset has been archived at the NEODC for the use of NERC scientists outside of BGS and CEH (who have made their own arrangements for internal distribution of the data).