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Terrain Elevation for Real Locations

Postby martink » Sat May 05, 2018 2:36 pm

Making a flat model with lots of buildings presents one set of challenges; making a reasonably accurate model of open and hilly country (e.g. Blea Moor) presents another set entirely.

There is a UK government website that has free-to-download aerial LIDAR (laser-radar) elevation data for much of the country, at 1m and 2m resolutions. The files are in a simple text format, so can be easily read and processed by suitable software. For a quick feasibility study, I simply downloaded some into Excel and plotted that as a surface chart, and was very impressed by the results. So, it looks like I will have to write some custom software to convert this into something that can be used directly.

I'll post more on this when I've written the software and improved the techniques.

FWIW, the data for Ribblehead is at https://environment.data.gov.uk/ds/surv ... ?grid=SD77

And here is a sample Excel plot showing the Blea Moor end of the Ribblehead viaduct at 2m resolution. It even shows the stone walling and footpaths!

rh-lidar1.jpg
rh-lidar1.jpg (159.64 KiB) Viewed 632 times
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Re: Terrain Elevation for Real Locations

Postby martink » Thu May 10, 2018 1:17 pm

Doing some more experiments on this, working towards a tool to help with building the track beds, making cutout elevation profiles as supports for the scenery, and 3d printed full-terrain models. The next addition is superimposing the baseboards.

The Ribblehead / Blea Moor area, flattened to remove the 1 in 100 gradient, with 5m contours (10mm on the model)...

test1.jpg
(389.41 KiB) Not downloaded yet


For a bit of contrast, just to the west of Plymouth, with 10m (20mm) contours and no adjustments...

test2.jpg
(429.19 KiB) Not downloaded yet
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Re: Terrain Elevation for Real Locations

Postby dkightley » Thu May 10, 2018 8:42 pm

I recognise that last image!! ;) ;)

And the website you've quoted is where I got the data from when I wanted to sort out contours for The Bridges at Saltash. But I'can't fully remember exactly how I processed the data....but I did end up with 5m contour lines overlaid onto a Google Earth image:
Capture1.PNG
Capture1.PNG (2.22 MiB) Viewed 577 times

At scale size, 5m works out at 11.1 mm...which is quite easy to gauge if you work with insulation foam as a ground material. I have some cheap vernier callipers that have a piece of wire as a depth gauge, and simply pierce the wire into the foam to measure the depth.
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk
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Re: Terrain Elevation for Real Locations

Postby martink » Sun May 13, 2018 5:32 pm

After another few hours fiddling, all still in rough form, but getting close to usable.

Ready to 3d print...

test43d.jpg
test43d.jpg (98.01 KiB) Viewed 539 times


Cutout diagrams for foam sheets at selected elevations/contours with a 300mm grid...

test5.jpg
test5.jpg (69.3 KiB) Viewed 539 times


Clipping to the actual baseboards (the bottom one is deliberately distorted to compensate for some compression)...

test4.jpg
test4.jpg (133.96 KiB) Viewed 539 times
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