I tried to warp a raster image being in latlong representation
into some projected systems like Aitoff, but the world being
rotated, the poles being not at the center of the top of the
In proj4 you can use +ob_tran +o_lon_p=0 +o_lat_p=0 +proj=anything
to achieve this.
However, since OGRSpatialReference reimplements (a subset of)
the proj parameter parsing, +ob_tran is not available.
- is my goal somehow simply achievable, just I can't figure how?
If so, please show me how!
- if it is not:
Basically what happens is that when I give gdalwarp a proj4
projection definition, it parses it, then it stores it in
a tree similar to the strukture of WKB. It gives the
WKB to a function which in turn converts it back to proj4,
and then initializes the proj4 projection objects with that
I tried to manually intervene into the last step, and I
succeded, I achieved my goal.
Now I am planning to create a patch that makes OGRSpatialReference
similar to a Perl scalar variable: When it is initialized with
a proj4 definition, it keeps that definition, and uses that if
only that is needed. However, when something else is also needed,
OGRSpatialReference automatically coerces itself into the
The goal is to achieve that through a simple gdalwarp session
OGRSpatialReference should be happy with either representation,
which makes it possible to use any proj4 projections. (I
beleive it is always a design flaw to reimplement an interface
of a library, sync keeping in sync the features is not a possible
task to do.)