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

[Phil Endecott]

Chris Hill write:
> 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?

No, I've just processed the raw values in their OSGB form.

I don't really have the skills to do reprojection and tiling and
serving the tiles as a map layer; if people actually want to use
this, someone else will need to do that.

> 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.

The data does at least indicate its age.


Regards,  Phil.