LiDAR Lens for Wiltshire

This post has a companion short film A LiDAR lens for Wiltshire, which shows the Lens at work in two minutes: the sun turning over the field banks in Great Ridge Wood, six ways of drawing the same ground, Stonehenge, and What's here? on a barrow beside it.

Anyone who has walked Wiltshire for long knows the ground is full of lumps and dips that the aerial photographs don't explain. Crops, hedges and trees hide a great deal. LiDAR takes the vegetation away and leaves the bare earth, and the Environment Agency has kindly flown most of the country and made the results free. The snag has always been getting the best from it without a GIS degree and a lot of patience.

So I have built something to make it easier, and it is now open to anyone: the LiDAR Lens for Wiltshire. It is free, there is no login, and it works on a phone as well as a desktop.

What it does

It covers all of Wiltshire and Swindon, about 3,800 km², using the Environment Agency's 1 m LiDAR composite terrain model laid over Esri aerial imagery, with OpenTopoMap as a background map.

The idea is simple. A circular lens sits on the aerial photo, and you drag it about and resize it to see the bare ground underneath. Inside the lens you can choose how the ground is drawn:

• hillshade, lit from a single direction or from several
• slope
• local relief model
• sky-view factor
• red relief

There are controls for sun angle, vertical exaggeration and colour, so you can tease out the faint stuff. Low sun, a bit of exaggeration and a slow sweep across a field is surprisingly addictive.

What’s here?

Click a spot and the "What’s here?" panel gives you plain measurements: local relief, size, elongation and edge slope. It also lists nearby recorded sites from Historic England's open data (scheduled monuments, listed buildings and aerial investigation mapping) and from OpenStreetMap, with links to the records.

Other bits

• Historic OS maps from the National Library of Scotland (25-inch, six-inch and one-inch, roughly 1880s to 1920s) as overlays, handy for comparing old field boundaries and tracks with the ground today
• Wiltshire Council public rights of way
• Go to a grid reference, place name or postcode, or "Use my location" when you're out in the field
• An elevation profile, share links, keyboard shortcuts and a help panel

Please use it responsibly

The public version contains no county Historic Environment Record data but a link to where the data can be obtained from is provided, observing uncertain copyright restrictions. Please respect landowners and stick to rights of way. Never dig or metal-detect on sites; scheduled monuments are protected by law. If you think you have found something new, report it to the Wiltshire HER at archaeology@wiltshire.gov.uk. They would much rather hear about it than have it dug.

Other counties welcome

There is nothing special about Wiltshire here, apart from it being the best county. The code is on GitHub under the MIT licence, and PROTOCOL.md walks through, step by step, how to build the same thing for your own patch. If you fork it for another county, do let me know.

I built it with a good deal of help from Grok Bot, and it is hosted on Cloudflare. It will have bugs and rough edges, so please leave a comment below with feedback, ideas, or anything interesting you spot.

Credits

• LiDAR: Environment Agency, Open Government Licence
• Aerial imagery: Esri
• Recorded sites: Historic England, Open Government Licence
• Historic maps: National Library of Scotland, CC-BY. Reproduced with the permission of the National Library of Scotland
• Public rights of way: Wiltshire Council, Open Government Licence; contains OS data. This is not the legal Definitive Map
• Map data © OpenStreetMap contributors
• Background map: OpenTopoMap, CC-BY-SA

Notes on the film

Every shot is a screen capture of the public LiDAR Lens, made frame by frame with the viewer's own controls, so what the film shows is what the site shows. Places: Great Ridge Wood (field banks under the trees), West Woods near Lockeridge, Stonehenge, and the disc barrow 220 m south-west of Stonehenge (NHLE 1012385). The background throughout is the National Library of Scotland's six-inch Ordnance Survey map (one-inch for the county view), reproduced with the permission of the National Library of Scotland (CC-BY). LiDAR: Environment Agency LIDAR Composite DTM 1 m (OGL). Music: original.