Spaced Out ::

As mentioned in an earlier post, the OS has now released, what was somewhat sketchy, Terrain 5. The website and technical specs are both quite scant of detail but looks to be photogrammetrically derived and on a rolling 3-5 year programme of maintained updates however “only required when real-world change has occurred; for example, a new motorway cutting.” Note that this appears to be new photography, infilled with Landform PROFILE for about 16% of the total area. This isn’t good news, but they do envisage this will become a 100% “full coverage” eventually. For changes to the natural environment (e.g. a meandering river), how do they know how often they need to re-survey? Positional accuracy is 1.5-2.5, although I can’t obviously see a statement on vertical accuracy. Height data rounded to the nearest centimetre.

This’ll be interesting to play with!