I'm playing around with R Rayshade, which creates lovely 3D terrain images using GeiTIFFs. I've been testing it out with SRTM 1 Arc-second images from USGS, but these are quite low resolution. OS provides large scale elevation data in Terrain 50. These come as ESRI shapefiles; when I load them into QGIS they appear as contour lines. How can I convert these into a DTM TIFF? I have tried the TIN interpolation tool but it crashes QGIS hard every time, so I suspect I'm not doing something right.

The data is also available in GML, ASCII Grid & GML, and Geopackage, if any of those are easier to work with.

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    ASCII Grid is a raster format, that should do what you're after; hopefully they're zipped for download as ASCII is the 2nd worst wasteful raster storage (XYZ is the worst). Convert to GeoTIFF with GDAL Translate -of GTIFF from command line or QGIS Raster::Translate. Apr 27, 2020 at 7:05
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    At the OS Opendata site you chose the wrong download format. You need the ASCII Grid (.asc) files.
    – nhopton
    Apr 27, 2020 at 7:27

1 Answer 1


As mentioned in the comments, you need to download the .asc grid format from the download page (see image below). After that you can use QGIS > Raster > Translate to convert the .asc grids to GeoTIFF. The data does download in individual tiles so you may also need to mosaic them or create a virtual raster or similar

  • Thanks. I found an R script to merge .asc files into one which worked well.
    – user36735
    Apr 28, 2020 at 12:08

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