Getmapping Height Data

Getmapping’s height data provides the most up to date and detailed national height data for Great Britain. Derived from our digital aerial photography, it is the product of a DTI-funded research program to create accurate elevation data using semi-automated extraction algorithms.

The result provides a product which is much more accurate than other medium resolution height datasets on the market. Comparable to LiDAR in detail and definition, Getmapping height data comes at a fraction of the cost of LiDAR and provides national coverage.

The availability of matching aerial photography also provides working ‘intelligence’ and the ability to create 3D environments for further investigation or display.

Getmapping height data is available as a Digital Surface Model (DSM) and as a Digital Terrain Model (DTM).

·          2m posting DSM and 5m DTM. (1m posting is available as a bespoke product)

·          Horizontal accuracy less than +/- 40cm RMSE.

·          Vertical accuracy less than +/- 60cm RMSE.

Digital Surface Model (DSM)

The first surface model is produced using the digital stereo aerial photography acquired by Getmapping. The data is acquired and processed independent of any OS datasets and is therefore free from any third party copyright. The process takes advantage of semi-automatic algorithms and the superior quality of the digital camera technology to produce a clean first surface model. This requires only minimal manual editing to remove gross errors and to accurately map the drainage network. The result is a DSM with a 2m posting and a vertical accuracy RMSE of around 50cm, with sub-pixel horizontal accuracy. For practical comparison, the accuracy of our data in open areas is directly comparable with LiDAR.

Digital Terrain Model (DTM)

The DSM is edited to produce a 5m DTM product. Getmapping uses a suite of algorithms to semi-automatically edit the DSM and remove unwanted surface features such as buildings and vegetation. These algorithms include a routine which reduces the woodland canopy areas based on a bounding polygon. This requires some manual intervention to create bounding polygons for woodland extents and identify true ground level. In addition, break lines are captured where required to ensure true terrain features are not removed and that bodies of water, such as lakes, remain flat. The result is a 5m posted DTM with a vertical accuracy of less than 60cm RMSE.

Call us on +44 (0) 1252 845 444 or