The Assize Courts, Devizes, a 3D model

 

https://timdaw37.github.io/assize-courts-3d

Wiltshire Museum is redeveloping the old Assize Courts. To help me visualise the plans I built a 3D model from the planning drawings so you can see the building as it is now and as it's planned. You can walk round it, look inside the courtrooms and entrance hall, and switch between the two views.

I'm an amateur, and this is version 1. It was made without specialist architectural tools, from the published planning drawings, LiDAR and open map data. It won't be perfect, but I don't think it's bad. Corrections are welcome.  The interiors still need refining.

Explore it here: https://timdaw37.github.io/assize-courts-3d

The model is open source and free to reuse. The code is on GitHub at TimDaw37/assize-courts-3d under the MIT licence, so you can copy it, adapt it and share it, as long as you keep the credits. If you spot something wrong, such as a window in the wrong place, a missing detail or a height that looks off, please tell me in the comments or raise an issue on GitHub.  Please keep the data credits (Environment Agency LiDAR, OpenStreetMap, Historic England and OS) when you reuse it.

Avebury and Stonehenge in 3D, rebuilt on the LIDAR

The two landscape fly-throughs, Avebury and Stonehenge, have been rebuilt from the ground up. Both were first made on Ordnance Survey Terrain 50, a 50 m height grid with 10 m colour bands. That is fine for the shape of the downs, but nothing archaeological survives in it: Silbury Hill had to be cut out of the terrain and modelled, and every bank and barrow was drawn on top of a surface that could not show it.

Both models now stand on the Environment Agency's 1 m LIDAR terrain model. The ground is a 5 m (Avebury) or 6 m (Stonehenge) mesh for shape, shaded from the full 1 m data, so the henge ditch, the barrow groups, the lynchets and the hollow-ways are the surveyed surface rather than a drawing of it.

As it is today, and as built

Each model now has two views.

• As it is today shows the LIDAR surface alone, with the barrows as rounded stumps, the Cursus banks a few centimetres high, and the roads, plantations and Larkhill camp alongside them.
• As built cuts the ground away under each monument and lays a fresh-chalk reconstruction on the ground beneath. The phase buttons add each period's earthworks in turn, from the Mesolithic posts to the Middle Bronze Age fields.

The reconstructions are indicative: the plan is the surveyed one; the heights and depths are typical original dimensions, not measurements.

Avebury: what the LIDAR changed

• The henge. The ditch now follows the line the LIDAR traces, 161 to 200 m from the centre, not a 210 m circle. The four causeways sit where the LIDAR ditch shallows, at bearings of about 73°, 165°, 254° and 331°, rather than exactly north, south, east and west. The ditch is still five to six metres below the bank today.
• The stones. The outer circle has 98 stones (it had 44), the inner circles 27 and 29 (they had 12 each), with the Cove and the Obelisk added.
• West Kennet long barrow. The surviving mound is 3.3 m high and 94 m long, and its high, broad end is to the east (bearing 85°). The earlier model had the façade at the west end.
• East Kennett long barrow. It lies NW–SE, broad end to the south-east, 28 m from the OpenStreetMap position.
• Round barrows. Eight of the 25 were matched to mounds that survive in the LIDAR. The rest have been ploughed out and stay at their recorded positions.
• Silbury Hill is the LIDAR mound itself. The as-built view recuts its quarry ditch.

Stonehenge: monuments from Historic England's aerial mapping

The Stonehenge model goes further. Its monuments now come from Historic England's aerial investigation mapping, the bank and ditch outlines plotted from aerial photographs and LIDAR, rather than from OpenStreetMap points. That data puts 843 prehistoric bank and ditch features in the frame, sorted into the phases by monument type and period.

• Early Neolithic: the cursuses, the causewayed enclosures and the long barrows.
• Late Neolithic: Stonehenge, Durrington Walls, Woodhenge and Coneybury.
• Beaker and Early Bronze Age: more than five hundred round barrows and ring ditches, and the Avenue.
• Middle Bronze Age: field systems and lynchets.

For each mapped earthwork, the as-built view lays down a 2 m surface: the LIDAR with the surviving earthwork smoothed away, and the bank and ditch rebuilt on the mapped plan.

• The Greater Cursus. The old model drew it as a straight east–west line at one northing. The mapped cursus is angled, with about 340 m of northing between its ends, and closes on the long barrow Amesbury 42 at the east. Where Historic England's mapping has gaps in the banks, the model leaves them.
• The fields. The earlier model had a generated coaxial grid, labelled as indicative. That has gone. The Middle Bronze Age view now picks out only the field banks and lynchets that are mapped.
• The Mesolithic posts stand at their surveyed positions in the old car park (Cleal et al. 1995). They no longer appear in the Neolithic views; they did not stand for four thousand years.
• Names and phases. Bluestonehenge is now West Amesbury henge, and the Avenue is shown with the Beaker period, when it was dug.

The stones, the timber circles at Woodhenge and Durrington, Larkhill causewayed enclosure and West Amesbury henge are placed by hand from published plans. Larkhill and West Amesbury leave nothing visible in the LIDAR.

Using them

• Moving: drag to turn, scroll to zoom toward the pointer, right-drag to pan; W, A, S and D walk across the ground. Double-click anywhere to move the centre of rotation there.
• Readout: shows the grid reference and height of whatever you are looking at.
• Save still: writes the current view as a PNG at twice screen resolution, with the labels and credits drawn in.
• LIDAR grey: swaps the landscape colour for a plain hillshade.
• Guided tour: still runs through each period with captions.
• Vertical slider: the vertical scale is exaggerated so the chalk reads; at ×1 it is true to life.

They are heavy pages, built for a desktop or a large screen. On a phone, adding ?lite to the address loads a coarser mesh without shadows; very old phones may still not manage the Stonehenge textures.

The Stonehenge model is the phased, as-built companion to the Stonehenge landscape flyover, which stays the place for the ground as it is now, the sky and alignment checks.

Ground: Environment Agency LIDAR Composite DTM 1 m, © Environment Agency copyright and/or database right 2022 (Open Government Licence). Monuments: contains Historic England data © Historic England 2026 (Open Government Licence), aerial investigation mapping; © OpenStreetMap contributors (ODbL). Reconstructions are indicative.

Cheddar to Bath , via Bristol November 1940 Aerial Film

The previously blogged Wiltshire run is the second half of a much longer sortie. NARA holds 254 prints from the two cameras under box GX 10484, and the item records place them on a single loop. The aircraft crossed the Devon coast at Sidmouth (L 1), flew north past Honiton to the Blackdown Hills, then north-east by Taunton, Bridgwater and the Levels to Cheddar, the Mendips and Bristol. North of Filton it turned east and south, and came back by Doynton and Keynsham to Bath and Freshford, where the Wiltshire frames begin at L 109. After Wiltshire it crossed the New Forest and left the coast at Barton-on-Sea (L 148): some 255 km on the long-lens camera alone.

The film above joins the long-lens frames from Cheddar to Freshford, L 56 to L 108. Fair-weather cumulus covers much of the Mendips, Dundry and Bristol (L 62–88); the ground still matches between the clouds, so the frames join, but the clouds sit far above the ground and shift between exposures. Exposure 86 and exposure 91 are not in the NARA set. L 86 is bridged by a small overlap between 85 and 87; L 91 leaves a short break in the film.

Over Bristol the frames come closer together. Over the Mendips successive frames are about 1,000 scanned pixels apart, over the city about 600, and the camera clocks agree: roughly one exposure every 20 seconds from L 56 to L 76, against one every 10 seconds from L 76 to L 85 (minute-hand readings by eye, good to about half a minute). NARA lists L 87–92, north of Filton, as obliques, although at least L 88 appears near-vertical; the label may reflect the aircraft banking into the turn. No record found names a target.

Bath is clear. On L 105 the Royal Crescent and the Circus stand out above Royal Victoria Park, seventeen months before the air raids of April 1942.

Bath on L 105, 29 November 1940: the Royal Crescent (centre) facing Royal Victoria Park, with the Circus above it. Turned to read roughly north-up. Luftwaffe, NARA RG 373, GX 10484.

Bristol through broken cloud, Bedminster to Ashley Down, L 76–84.

Notes on the film

The landscape film runs at about four times real speed and is turned so that the aircraft flies left to right. Each frame is captioned with its exposure number, NARA's nearest place name and its clock reading. The Cheddar to Bath film is a director's cut, without captions, and ends where the Wiltshire film begins. The music is original.

Sources

• National Archives and Records Administration. German Flown Aerial Photographs, 1939–1945. RG 373, series NAID 306065; file units GX 10484 SG. catalog.archives.gov/id/306065
• National Archives and Records Administration. Target Dossiers Pertaining to the British Isles, 1938–1945. RG 242, series NAID 3371016. catalog.archives.gov/id/3371016
• National Collection of Aerial Photography. German Air Force (Luftwaffe), GB 551 NCAP/4. ncap.as.atlas-sys.com
• Luftwaffedata Wiki. Aufkl. Gr. 123 1940. luftwaffedata.co.uk
• Luftwaffedata Wiki. Aufklärungsgruppe Ob.d.L. luftwaffedata.co.uk
• Daw, T. 2026. The Luftwaffe's Wiltshire. sarsen.org; map at wiltshire-luftwaffe.netlify.app

All photographs: Luftwaffe, 29 November 1940; US National Archives, RG 373, GX 10484, listed as Use: Unrestricted. Frame matching, measurements and film: T. Daw. Methods and scripts: github.com/TimDaw37/wessex-films.

Rising Sea levels at Woolacombe and Saunton

This is a side-hustle from my Ramson Cliff erratic post. While I was looking through the 1940 German reconnaissance photos for that, I wondered whether we could show the effect of rising sea levels on the beaches at Woolacombe and Saunton.

The result is a small interactive map: Woolacombe and Saunton at 12:44 BST, 31 August 1940.

Making it a fair comparison

To make it fair, we matched the position in the tide cycle as closely as we could with modern satellite photographs, then overlaid them. Matching the tide height alone isn't enough. On a flat beach, where the water's edge appears also depends on:

• Time after low water. The 1940 photos were taken about 90 minutes after low water.
• Rising or falling. A falling tide leaves wet sand and pools behind it, so the edge seen from the air lags the real water level. A rising tide pushes in over drier sand.
• The size of the tide. 1940 was a mid-sized tide (6.8 m range at Ilfracombe). Big spring tides move faster and push the waves further up the beach.

For example, a Sentinel-2 image from 27 September 2018 caught the sea at almost exactly the 1940 height. But the tide was falling, 100 minutes before low water, on an 8.3 m spring tide. It looks similar, but it isn't the same moment. So I kept only modern images taken on a rising tide, within 20 minutes of the 1940 timing, and with a tide range within 1.5 m of 1940's.

How the photographs were matched

The photographs were matched in the following manner:

• Time. Each German frame shows the camera's clock. It ran on German summer time (CEST), one hour ahead of British Summer Time, so the Woolacombe photos were taken at about 12:44 BST. A tide model for Ilfracombe, checked against Newlyn's real 1940 record, gives the tide at that minute.
• Tilt. The camera wasn't pointing straight down. It was tilted about 12°, from roughly 8 km up. I worked out the camera's position and tilt and laid each photo over the Environment Agency LiDAR ground heights, so that hills and cliffs fall in the right place.
• Pinning. Each photo was then pinned to thousands of features that haven't moved since 1940: roads such as Marine Drive at Woolacombe and the Saunton road, buildings, and hedge and field corners.
• Accuracy. On fixed features the 1940 photos typically sit within 2–3 m of today's imagery. Marine Drive lines up within 3 m. Among the Saunton dunes, where there is little to pin to, it is about 10 m.
• Modern images. These are Sentinel-2 and Landsat scenes from 1985 to 2023, each timed against the same tide model.

What we'd expect to see

Newlyn, the gold-standard tide gauge, shows about 20 cm of sea-level rise since 1940. On Woolacombe's gentle beach, 20 cm moves the waterline only about 8 m. On the flatter sand at Saunton the LiDAR puts it at around 20–30 m.

Conclusion

On these sorts of beaches it's invisible. Sand moving about and the natural spread of the waterline swamp it. On 1940 film, wet sand and shallow water look alike, so the 1940 edge alone can shift by up to 50 m depending on how it's read. Of 106 modern Landsat and Sentinel-2 readings, 27 match the 1940 tide. On those, the water's edge sits a median of −0.08 m from the predicted tide at Woolacombe and +0.16 m at Saunton. Neither shows a trend that stands out from the noise. The rise is real, but you measure it with a tide gauge, not on a sandy beach.

Explore the map. 1940 photos: U.S. National Archives, RG 373. Contains modified Copernicus Sentinel data. LiDAR © Environment Agency (OGL).

Looking for the Ramson Cliff Erratic in 1940 - the film

The Ramson Cliff boulder has had me hooked for over a year now (the mystery, the 2025 visit, the second thin section and last month's post), and the full story is in the paper in Quaternary Newsletter 167. One question kept nagging at me. The stone was found in 1969 at SS 4356 4070, out in the field on Baggy Point, and moved to the field edge in the early 1970s. Was it already sitting there in 1940, and would a wartime aerial photograph show it?

So I flew in to have a look, using a Luftwaffe reconnaissance photograph taken over North Devon in the summer of 1940.

How I made it

The photographs come from Luftwaffe sortie GX 10006 SD, flown on 31 August 1940. Each frame has the camera's clock photographed in the corner. The clock in the neighbouring frame reads 12:45 BST, which puts the frame over the find spot at about the same moment. I lined the frames up against the modern map, tightening the fit around Baggy Point using the field banks that show on the Environment Agency LiDAR. Then I stitched them into a mosaic and flew a virtual camera in from the south over Croyde, descending and tilting down until it looks straight down on the target.

On the approach: the 1940 fields of Baggy Point, built from sortie GX 10006 SD.

The limit is resolution. The National Archives scans of these frames come out at about 1.5 m per pixel on the ground. The boulder is 105 x 55 x 38 cm and weighs 378 kg, so it is smaller than a single pixel. I never expected to see the stone itself. What I was looking for were the things a big stone in a field does to the land around it: livestock tracks converging on it, a trampled or poached patch, ploughing that bends round it, or an unploughed island left where the plough couldn't go.

Over the target: the circle marks the 1969 find spot, SS 4356 4070, on the 31 August 1940 photograph.

What it shows

Honestly, nothing. In 1940 the find spot lies in a strip of grass inside the cliff-top boundary. With the contrast pushed up there are no tracks running to it, no worn patch, and no sign of cultivation avoiding it. The other photographs I have looked at, GX 11967 (23 March 1941) and RAF 106G/LA/132 (14 February 1945), are no clearer. That doesn't prove the stone wasn't there: a stone smaller than a pixel in a grass field could easily leave no trace. But the wartime air photos can't settle it either way.

The film ends on the LiDAR, which picks out the cliff-top field edge where the stone sits today.

Credits

Aerial photographs: US National Archives, Record Group 373. LiDAR: Environment Agency, contains public sector information licensed under the Open Government Licence v3.0.

LiDAR Lens Ynys Môn

 

Mae LiDAR Lens Ynys Môn yn dangos Môn gyfan mewn LiDAR 1 m, mewn gwyliwr cyflym am ddim sy'n gweithio cystal ar ffôn mewn cae ag ar gyfrifiadur. Mae LiDAR Llywodraeth Cymru yn cwmpasu'r ynys gyfan bron, ac mae pob teil yn cael ei gadw gyda'r lens, felly mae'n llwytho'n gyflym ble bynnag yr ydych. Mae Bryn Celli Ddu i'w weld yn ei dirwedd, Barclodiad y Gawres ar ei bentir, strydoedd a muriau Caergybi yn dod i'r golwg, a'r cytiau crwn a'r hen gaeau ar Fynydd Tŵr yn neidio allan o lethrau'r mynydd. Mae'r enwau lleoedd yn Gymraeg yn gyntaf, gyda'r Saesneg mewn cromfachau, ac mae pob un o 147 heneb gofrestredig Cadw ar yr ynys wedi'u marcio, gyda dolen i'w hadroddiad. Does dim angen mewngofnodi, dim cyfrif a dim hysbysebion.

Sut mae'n gweithio

Symudwch a chwyddwch ar draws yr ynys, neu defnyddiwch y blwch Go to i neidio i le neu gyfeirnod grid. Ar ffôn, mae Use my location yn eich rhoi ar y map yn y fan lle rydych yn sefyll, sy'n ddefnyddiol yn y maes. Daw'r 146 enw lle o restr Comisiynydd y Gymraeg o enwau lleoedd safonol, er enghraifft Biwmares (Beaumaris) a Llangefni. Cliciwch ar heneb gofrestredig i agor ei hadroddiad gan Cadw, a dilynwch y dolenni i Archwilio a Coflein am y cofnod amgylchedd hanesyddol ehangach.

Defnydd teg

Nid oes unrhyw ddata o'r cofnod amgylchedd hanesyddol wedi'i gopïo i'r lens; mae'n cysylltu ag Archwilio a Coflein, sy'n parhau i fod y lle i chwilio. Parchwch dirfeddianwyr, a chofiwch fod henebion cofrestredig wedi'u diogelu gan y gyfraith. Nid yw gweld rhywbeth yn y LiDAR yn rhoi caniatâd i fynd i edrych arno.

Cydnabyddiaeth

• LiDAR: DTM 1 m Llywodraeth Cymru (MapDataCymru), Trwydded Llywodraeth Agored f3
• Enwau lleoedd: Comisiynydd y Gymraeg, rhestr o enwau lleoedd safonol Cymru
• Henebion cofrestredig: Cadw, Trwydded Llywodraeth Agored
• Dolenni: Archwilio a Coflein (CBHC)

Am Gymru a Lloegr gyfan, a'r lensys eraill, ewch i lidarlens.sarsen.org. Mae'r cod ar GitHub. Croeso i chi adael sylwadau, ac unrhyw beth diddorol a welwch, isod.

LiDAR Lens Anglesey

LiDAR Lens Ynys Môn puts the whole of Anglesey in 1 m LiDAR into a fast, free viewer that works as well on a phone in a field as on a desktop. The Welsh Government's LiDAR covers essentially the entire island, and every tile is stored with the lens, so it loads quickly wherever you are. Bryn Celli Ddu sits in its landscape, Barclodiad y Gawres crowns its headland, the walls and streets of Caergybi (Holyhead) show through, and the old hut circles and fields on Mynydd Tŵr (Holyhead Mountain) leap out of the hillside. Place names are Welsh first, with English in brackets, and all 147 of Cadw's scheduled monuments on the island are marked and linked. There is no login, no account and no adverts.

How it works

Pan and zoom across the island, or use Go to box to jump to a place or grid reference. On a phone, Use my location puts you on the map where you are standing, which is handy in the field. The 146 place names come from the Welsh Language Commissioner's list of standardised Welsh place names, such as Biwmares (Beaumaris) and Llangefni. Click a scheduled monument to open its Cadw report, and follow the links out to Archwilio and Coflein for the wider historic environment record.

Fair use

No historic environment record data is copied into the lens; it links to Archwilio and Coflein, which remain the places to look things up. Please respect landowners, and remember that scheduled monuments are protected by law. Seeing something in the LiDAR is not permission to go and look.

Credits

• LiDAR: Welsh Government 1 m DTM (DataMapWales), Open Government Licence v3
• Place names: Welsh Language Commissioner, list of standardised Welsh place names
• Scheduled monuments: Cadw, Open Government Licence
• Links: Archwilio and Coflein (RCAHMW)

For England and Wales as a whole, and the other lenses, see lidarlens.sarsen.org. The code is on GitHub. Comments and anything interesting you spot are welcome below.