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

[Chris Hill]

On 24/09/15 18:41, Phil Endecott wrote:
> Chris Hill wrote:
>> Suitably processed this could provide a source of building outlines.
>
> Yes, I think it could be very useful for that.  I've had a play
> and rather than doing shaded relief I've just converted the height
> directly into a grey shade.  I've then applied ImageMagick's edge
> detection filter.  Here are a couple of fragments near Manchester
> taken from the 25cm resolution data; in each case the first image
> is the direct height-to-grey and the second is edge-detected:
>
> http://chezphil.org/tmp/lidar1.png
> http://chezphil.org/tmp/lidar1_ed.png
> This is at SJ 8099, or maybe search for Chaseley Road to find it
> on a map.  You could easily trace building outlines from this and
> determine roof shapes and could measure building heights by subtracting
> roof from ground, with some suitable tool.  You could also trace
> trees and some walls.
>
> http://chezphil.org/tmp/lidar2.png
> http://chezphil.org/tmp/lidar2_ed.png
> This is SE of the last one at SJ 8198.  The gasometers (presumably!)
> are at the junction of West Egerton Street and Liverpool Street.
> I find it interesting that you can count the number of ridges in
> the large warehouse roofs.  You can also easily identify carparks!
>
> How would people find this for tracing compared to photo imagery?

Looks interesting. Have you reprojected the images from the OS 
projection they come as to WGS84 that OSM uses?

Some of the data was gathered in 2009, so Bing aerial images can be more 
up-to-date, but for most buildings this isn't a problem.

-- 
Cheers, Chris
user: chillly