Lansdown LiDAR at last!

While we have been doing geophysics on Lansdown since 2018, we have been hampered by very poor LiDAR coverage to supplement earthwork images and provide height data.

Now, the Environment Agency has issued new data with one metre resolution, available as DSM (showing trees and houses) and DTM (showing ground level, even under tree cover). Thanks to Tim Lunt, who noticed the new material, John Oswin has been able to construct a LiDAR map for all of Lansdown and surrounding area. The new data comes in 5 km square blocks, and needless to say, two blocks join on Lansdown.

He has constructed a 10 km square map (see below). Bath is just off the bottom of the map, Lansdown can be seen as the flat, uniform grey area bottom left, while Marshfield can be seen at the top right. Note this is DTM (so trees and buildings have been removed).

Needless to say, 100 square kilometres at 1 metre resolution makes for an enormous data file, but the benefits are worth it. This can be seen when we home in on Little Down Field, shown at the top of this page and repeated below, complete with added 1 m contours in blue, with the earthworks showing up very clearly and now complementing our resistance and magnetometry surveys. The only thing you cannot see is the snow that was on the ground when we did the survey!

Little Down Field is at the north east tip of the Lansdown plateau and is an Iron Age and Roman site. BACAS did geophysics surveys there in 2018 and the report is available to download.

LiDAR data is available under the Open Government licence v3.0 © Crown Copyright 2020