A lot is already done. Download away.

UK Lidar: https://data.gov.uk/dataset/lidar-composite-dsm-1m1

There's even some Unity plugins that will merge this lidar with satellite photos and openstreetmap and get you a 3d environment from all this data.

Does anyone know what the errors are and what accuracy the elevation data is?

All I can find is "spatial resolutions of between 25cm and 2 metres" and "Accurate elevation data ..."

Environment Agency LiDAR data has a vertical accuracy of 5-15cm +/- RMSE and a horizontal accuracy of 40cm +/- RMSE [1]

These kind of accuracy measures are usually relative to the national datum. They can be more accurate relative to other points in the same survey.

[1] http://www.getmapping.com/support/height-lidar-data/how-accu...

This has already been done for the Netherlands a few times, and is repeated every 5 or so years. See all the data in your browser here: http://ahn2.pointclouds.nl/

It has already been done for England too[0] (although the abstract says 'over 70% of England' so some parts must be missing).

I think someone made a Minecraft map out of the current data, will be interesting to see what is made from the update.

[0]https://data.gov.uk/dataset/lidar-composite-dsm-1m1

Not sure if this is the same map you're talking about, but Ordinance Survey made a map[0] using data they had in 2013, and then again in 2014. This was based on height data at 50m resolution.

It's hard to see how OS capture height exactly, I imagine via aircraft[1]. Not sure whether they are the source of the existing data the Environment agency has; I doubt it as their data has a max resolution of 5m while the government's is 1m.

[0] https://www.ordnancesurvey.co.uk/innovate/developers/minecra...

[1] https://www.ordnancesurvey.co.uk/international/knowledge/dat...

Most of the OS terrain data is now from pairs of aerial photos using photogrammetry. The older products were actually based on contours that were surveyed using more traditional techniques.

The Ordnance Survey converted their mapping data to a Minecraft world: https://www.ordnancesurvey.co.uk/innovate/developers/minecra...

So we are back to the IE6 days, I am supposed to open specific pages on specific browsers.

2017 is so retro, I wonder if I will be able not to use Chrome in 2018.

I guess it'll be just like the good old days with Firefox 1.5.

Done in Spain as well, free to download (RGB-colored .laz), but no online 3D viewer: http://centrodedescargas.cnig.es/CentroDescargas/buscadorCat...

Does not work in Firefox????

Nope it doesn't not, requires Edge or Chrome. Feels like IE wars again.

Some of the states in the US are doing this as well. For example, Tennessee.[1]

[1]: http://www.tngis.org/lidar.htm

Topographic (geodetic) shape is always changing with time. Radar inferometry from satellites gives the most repeated surveys, but has low spatial resolution. You can discern made-made, seasonal, and geological factors causing change. The American Geophysical Union meeting each December has several hundred papers on dynamic geodesy.

Any idea how the quality compares with just using Open Street Map elevation data?

OpenStreetMap does not have much of its own elevation data. (There is a way to tag elevation, but it is rather seldom done). Any project that shows you OSM data and elevation is probably pulling in third-party elevation data such as that from the Shuttle Radar Topography Mission (SRTM)[1].

[1] http://srtm.csi.cgiar.org/

I was pleasantly surprised to learn that Airbus sells a very nice Digital Elevation Model. It seems to be quite a lot better than the shuttle data everyone was using for a while.

http://www.intelligence-airbusds.com/worlddem/

The elevation data in OSM is mostly just an elevation data on peaks and such, not actually DEM stuff