182 reputation
9
bio website craig.stanton.net.nz
location Auckland, New Zealand
age 34
visits member for 3 years, 2 months
seen Jan 9 at 1:44

http://pct2007.org http://onemanwalking.com


Mar
6
revised Not seeing the actual data value in getObservation response from MapServer 6
showing more of my source code
Mar
6
asked Not seeing the actual data value in getObservation response from MapServer 6
Mar
6
answered MapServer SOS (Sensor Observation Service) Configuration
Feb
22
awarded  Student
Nov
4
comment Tiling rgba geotiffs using vrt rather than gdal_warp
I've written up the whole process on my blog incase anyone comes here and is starting from scratch. craig.stanton.net.nz/2011/06/07/usgs-map-tile-sets
Nov
3
comment Tiling rgba geotiffs using vrt rather than gdal_warp
The final command that build a valid VRT was gdalbuildvrt -srcnodata b4 -hidenodata map.vrt *.tif. See MerseyViking's answer for how I got there
Nov
2
awarded  Scholar
Nov
2
accepted Tiling rgba geotiffs using vrt rather than gdal_warp
Nov
2
comment Tiling rgba geotiffs using vrt rather than gdal_warp
Ah HA! I cracked it. The final command that build a valid VRT was gdalbuildvrt -srcnodata b4 -hidenodata map.vrt *.tif. After that the regular gdal2tiles.py worked a treat and I have the output I wanted.
Oct
26
comment Tiling rgba geotiffs using vrt rather than gdal_warp
Thank you for spending time on this. I'm still getting messed up results. With these two commands I get mostly transparent tiles with tiny little slivers between the original maps. gdalwarp TILED=YES -srcnodata "255 255 255" -dstnodata "255 255 255" translated.tif warped.tif and gdalbuildvrt -srcnodata 255 255 255 -hidenodata temp.vrt <warped files>.tif and in tiles that are no near the boundary I get the background (between the contour lines) being transparent too.
Oct
26
awarded  Teacher
Oct
24
comment Tiling rgba geotiffs using vrt rather than gdal_warp
Oh right. I avoided reszing the tifs in anyway, just cleared the unwanted borders with map noes etc. If I allowed white to be the transparent colour the output tiles would be largely transparent except for the contour lines and would look very bad laid over Google Maps. You said GDAL supports a mask layer, and I know gdal_merge is able to understand transparency, how would I get gdalbuildvrt to to do the right thing so I don't have to hunt for a colour that doesn't exist in any of the 30+ tifs I'm playing with?
Oct
23
comment Tiling rgba geotiffs using vrt rather than gdal_warp
What are the GCPs for? this images area already fully georeferenced so if they are for that then I'll leave them out. Unfortunately pure white is used in the map, as is pure black and it'd be pot-luck if I tried to guess at a colour that wasn't already in use.
Oct
23
awarded  Editor
Oct
23
revised Tiling rgba geotiffs using vrt rather than gdal_warp
added 275 characters in body
Oct
23
asked Tiling rgba geotiffs using vrt rather than gdal_warp
Oct
23
answered Is there any way of merging two sets of tiles with gdal2tiles?
Oct
23
awarded  Supporter
Sep
7
awarded  Autobiographer