Wales is 21,000 square kilometres.

COWI Mapping undertook to create and edit a new bare earth height model coverage of Wales with a 5 m resolution to meet an accuracy of 1.5 m RMSE.

Wales is covered by 7500 aerial images taken in 2006 by COWI, using their UltraCamD cameras.

Resolution of the imagery is approximately 40 cm, which proved more than adequate to meet the accuracy requirements.

The project was run in the UK, using Socet Set 5.3. The new ATE algorithms provided a superb raw data set which reduced the editing time.

Wales is extremely forested and the largest time factor in the DTM editing was removing woodland and forest areas.

A QA check of data, using over 1500 known points gave a RMSE result of 1.48 m for the resulting edited DTMs.

The project ran for 15 weeks with three weeks for data delivery.