When I project longitude -60, latitude 0 to mercator, I get the expected answer:
> echo "-60 0" | cs2cs +proj=lonlat +to +proj=merc -6679169.45 0.00 0.00
However, when I project it to oblique mercator with very similar parameters, I get a very different result:
> echo "-60 0" | cs2cs +proj=lonlat +to +proj=omerc +k=1.0 +lat_0=0 +alpha=0.0001 +lonc=0.00001 -8416502.68 -4.68 0.00
Shouldn't the results be approximately equal?
I couldn't use exactly 0 for parameters, since omerc won't initialize there.
I sense I'm doing omerc wrong: what's the right way?
EDIT: I am aware that omerc might have a minor bug for alpha<0: http://permalink.gmane.org/gmane.comp.gis.proj-4.devel/5773 but this shouldn't affect what I'm doing.