[gdal-dev] gdalwarp t_srs '+ortho +lat_0=90' projection problem

[Heiko Schröter]

Hello gdal list,

reprojecting raster images from epsg:4326 -> '+ortho +lat_0=90 lon_0=0' results in a not closed image, missing about 5-6°. (.i.e Pacman like)
Reproducable for '+lon_0=90,180 and 270'.

Now shifting 'lon_0=6/-6' resolves the issue and the map is closed.
Reproducable for every 'lon_0=84/96...'
Editing and fine tuning the .wld file won't resolve the issue.
The problem is reproducable with any image.

The wmap_work.gif image ca be downloaded here (185k):
http://iup.physik.uni-bremen.de/~schroete/wmap_work.gif

I need to display the closed images with viewprot from 'lon_0=0/90/270'.
What am i missing or doing wrong ?

Regards
Heiko



Commands used:
$ gdalwarp --version
GDAL 1.6.0, released 2008/12/04

$ gdalwarp -of GTiff -s_srs 'epsg:4326' -t_srs '+proj=ortho +lon_0=0 +lat_0=90' wmap_work.gif wmap_out.gif

The wmap_work.wld file:
0.1495016
0
0
-0.1495016
-180
90

$ gdalinfo wmap_work.gif | head -n 15
Driver: GIF/Graphics Interchange Format (.gif)
Files: wmap_work.gif
Size is 2408, 1208
Coordinate System is `'
Origin = (-180.074750800000004,90.074750800000004)
Pixel Size = (0.149501600000000,-0.149501600000000)
Corner Coordinates:
Upper Left  (-180.0747508,  90.0747508)
Lower Left  (-180.0747508, -90.5231820)
Upper Right ( 179.9251020,  90.0747508)
Lower Right ( 179.9251020, -90.5231820)
Center      (  -0.0748244,  -0.2242156)
Band 1 Block=2408x1 Type=Byte, ColorInterp=Palette
  NoData Value=126
  Metadata: