LiDAR guide · an IPR project
Coverage and limits
Where data exists
According to DGT, data is available for about 90% of mainland Portugal; the north-west is still in production. The survey covers the mainland only: the Azores and Madeira are not part of it. Always check your area in the Data Centre before planning work that depends on it.
What accuracy to expect
DGT states 10 cm vertical and 30 cm horizontal accuracy, with an average density of 10 points per m². In practice, the 50 cm DTM is excellent for reading landforms: watercourses, ridges, terraces, slopes. It is not a certified topographic survey: for permitting, cadastre or works with tight tolerances, you still need a surveyor.
Where to take care
- Water. The laser barely returns from water: reservoirs and ponds appear flat, at the surface level on the day of the flight.
- Very dense vegetation. In closed scrub and young eucalyptus stands, fewer points reach the ground and the DTM is interpolated.
- Bridges and culverts. In the DTM, a bridge can look like a wall closing the valley. Correct it before computing flow.
- Time. The data shows the ground between 2024 and 2025. Later works, tracks or ponds are not there.
How to cite
"Source: Direção-Geral do Território, LiDAR of mainland Portugal, 2024–2025". DGT releases the data as open data, with no restrictions on use, and states a CC BY 4.0 licence.