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| author | Frank Warmerdam <warmerdam@pobox.com> | 1999-03-18 16:34:52 +0000 |
|---|---|---|
| committer | Frank Warmerdam <warmerdam@pobox.com> | 1999-03-18 16:34:52 +0000 |
| commit | 565a4bd035b9d4a83955808efef20f1d8dfa24cf (patch) | |
| tree | 75785fc897708023f1ccdaf40079afcbaaf0fd3a /src/pj_inv.c | |
| download | PROJ-565a4bd035b9d4a83955808efef20f1d8dfa24cf.tar.gz PROJ-565a4bd035b9d4a83955808efef20f1d8dfa24cf.zip | |
New
git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@776 4e78687f-474d-0410-85f9-8d5e500ac6b2
Diffstat (limited to 'src/pj_inv.c')
| -rw-r--r-- | src/pj_inv.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/pj_inv.c b/src/pj_inv.c new file mode 100644 index 00000000..16dd90dd --- /dev/null +++ b/src/pj_inv.c @@ -0,0 +1,32 @@ +/* general inverse projection */ +#ifndef lint +static const char SCCSID[]="@(#)pj_inv.c 4.5 93/06/12 GIE REL"; +#endif +#define PJ_LIB__ +#include <projects.h> +#include <errno.h> +# define EPS 1.0e-12 + LP /* inverse projection entry */ +pj_inv(XY xy, PJ *P) { + LP lp; + + /* can't do as much preliminary checking as with forward */ + if (xy.x == HUGE_VAL || xy.y == HUGE_VAL) { + lp.lam = lp.phi = HUGE_VAL; + pj_errno = -15; + } + errno = pj_errno = 0; + xy.x = (xy.x * P->to_meter - P->x0) * P->ra; /* descale and de-offset */ + xy.y = (xy.y * P->to_meter - P->y0) * P->ra; + lp = (*P->inv)(xy, P); /* inverse project */ + if (pj_errno || (pj_errno = errno)) + lp.lam = lp.phi = HUGE_VAL; + else { + lp.lam += P->lam0; /* reduce from del lp.lam */ + if (!P->over) + lp.lam = adjlon(lp.lam); /* adjust longitude to CM */ + if (P->geoc && fabs(fabs(lp.phi)-HALFPI) > EPS) + lp.phi = atan(P->one_es * tan(lp.phi)); + } + return lp; +} |