Somewhat quietly the UK’s Environment Agency recently released their LIDAR data for much of England. Most people are probably thinking “so what!” but the myriad of wireless broadband operators are likely to be jumping with joy once they get to grips with what’s been released.

The LIDAR data is provided as digital elevation data suitable for GIS systems, including wireless propagation modelling tools, but that sets this data apart from the many other free elevation data is twofold:

  • It’s extraordinarily accurate!
  • It includes both terrain and surface models

Accurate? To put this in perspective, each pixel in the Ordnance Survey opendata terrain data is 50m by 50m while the Environment Agency pixels are just 1m across and some areas are just 25cm square. Most datasets provide a general feel for the landscape at a point but this data is incredibly granular showing every crease in the landscape.

But the really useful benefit is the release of surface models. Most elevation data is only released as terrain models, showing the underlying ground, which is perfect for civil engineering work but only partially useful for radio coverage models which also needs to know about tall trees and buildings – clutter.

If the OS opendata elevation data included a surface model its pixel size would miss many building completely but the EV data would not only capture a house, it might even pinpoint someone mowing their grass!

Together this means Environment Agency data provides a resource that should revolutionise that way wireless operators plan their network coverage.

As a quick example, I loaded a small area into QGIS and generated a 3d model using the 1m surface data.

As you can see it clearly shows the houses, trees, hedge rows – you can even see  vehicles on the roads! This is from the 1m model – the 25cm data would be far more detailed, probably too detailed for most modelling work and the files would be too big to sensibly work with.

The data has been released as ASCII Grid files which should load easily into most GIS and modelling tools, and can be downloaded here.

A word of warning. The data I downloaded contained an extraordinary number of decimal places suggesting that the EV has measured elevations down to the scale of a carbon atom. This made the files unnecessarily huge. I reduced the accuracy down to cm scale and it reduced the file sizes by over 60%. For example, the data for West Oxfordshire reduced from 16Gb to 6Gb by accepting I wouldn’t be able to resolve anything shorter than 1cm.

I suspect the EV may not be aware of the importance of what they’ve released but their engagement with open data will be applauded by many rural communities beyond the reach of reliable broadband.

  1. Alastair Duncan says:

    Thanks for the really interesting blog post. When we announced the release of LIDAR data back in June 2015, we set ourselves an ambitious target of making the data available by September. The complexity and size of the data meant that we needed to develop a delivery service that was robust, easy to use and able to deliver more data to a wider range of people than our current platform could manage.

    The issue with the double precision data values being used in the ASCII files, which you have raised in your article, was noted three weeks ago. It would however have been impractical to fix it at the time and still hit our deadline of releasing the data on 1 September. In the coming weeks the zip file of many 1x1km ASCII tiles will be replaced by a single 10x10km zipped ASCII tile, and the Z values in the new tiles will be to 3 decimal places (no more femtometers and attometers).

    We are very keen to make our fantastic LIDAR and other datasets as useful and usable as possible, and we hope that by removing the cost barriers to the data will make it possible for businesses and local communities to develop new innovative tools and techniques to further benefit the environment.

    • Adrian Wooster says:

      Thanks for commenting – this is a fantastic resource which I hope will make a massive difference to rural communities in the same way the OS had when they released their open data sets. I fully understand the z-value issue, and really look forward to seeing the updates.

    • Adrian Wooster says:

      Bob, you are right but when I downloaded the tiles for West Oxfordshire, the 1m resolution data included a very large proportion of the district. What I’ve loaded is impressive and extensive. The other operators I’ve spoken to about it are finding similar results in their initial forays as well.

  2. ian says:

    as far as we can tell, here in Scotland, you still have to pay for Lidar. This is very disappointing. The data revolution is, for now, on hold in Scotland!

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