[OSM-talk] Skybox for good imagery test

[Stephan Knauss]

I had a closer look at the imagery provided under the Skybox for good grant.
https://mapsengine.google.com/00979750194450688595-08887688179650036554-4/mapview/?authuser=0

Opening the GeoTiff directly in JOSM using the ImportImage plugin works 
but JOSM gets quite slow due to the large file size. So I decided to 
tile the image for easier viewing.

Alignment of the imagery looks fine. There is some distortion of the 
imgery compared to the existing OSM data. Without GPS tracks its 
difficult to say what is more accurate.

See for yourself around this area:
https://www.openstreetmap.org/#map=16/29.7137/91.7383

Data is here:
http://downloads.osm-tools.org/sb4g/

Browse either using a web browser or by adding a TMS layer to JOSM
tms[18]:http://downloads.osm-tools.org/sb4g/{zoom}/{x}/{-y}.png

I created the tiles from a 1.4 GB tif, resulting directory was 875MB. 
Creation took 16 minutes.

gdal2tiles.py -z 0-18 s02_20141006T032553Z-geo.tif sb4g

Keep in mind that the above imagery was no HOT activation. So using it 
for OSM is not allowed.
I assume someone at HOT will replicate the tiling once imagery is 
available and provide a TMS server.

Stephan