[Talk-GB] Environment Agency LIDAR datasets OGL licensed now available

[Phil Endecott]

Chris Hill wrote:
> I've had a go at extracting the height of buildings from the Environment 
> Agency LIDAR, and it seems possible.
>
> I loaded the EA data into a database and found all the height points 
> within the polygon of an existing building outline. The highest value is 
> the height of the building.

Well it's the altitude above sea level of the roof of the building.
Presumably what OSM wants to record is the height above natural ground
level or adjacent road level or similar.  I can think of various ways
of doing that, e.g. looking for the lowest point near but outside the
building outline.

I can also imagine looking at the distribution of heights within the
building outline and working out if it is a flat or a pitched roof.
And maybe working out which direction the ridge runs in i.e. which
wall it is parallel to.


Cheers,  Phil.