[Proj] Verification of inverse step in projection

José Luis García Pallero jgpallero at gmail.com
Sat Dec 12 12:10:00 EST 2009

I'm a new proj user and I have a doubt about the verification of
inverse step in projection. As the manual says (proj.4.3.pdf, page

"Some projections do not have inverse capability; a state that can be
determined by proj->inv==0."

But when I try to test:

projPJ pjStruct;
pjStruct = pj_init_plus("+proj=tcc +ellps=clrk66 +lon_0=90W");

At compilation time I obtain the error:

prueba.c: In function ‘main’:
prueba.c:22: warning: dereferencing ‘void *’ pointer
prueba.c:22: error: request for member ‘inv’ in something not a
structure or union

It says that inv is not a member of the projectios struct.
What is the correct way to check if a projection has inverse step?


José Luis García Pallero
jgpallero at gmail.com
/ / \
Use Debian GNU/Linux and enjoy!

More information about the Proj mailing list