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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_eck2.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_eck2.c')
| -rw-r--r-- | src/PJ_eck2.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/PJ_eck2.c b/src/PJ_eck2.c new file mode 100644 index 00000000..ebfdbda3 --- /dev/null +++ b/src/PJ_eck2.c @@ -0,0 +1,31 @@ +#ifndef lint +static const char SCCSID[]="@(#)PJ_eck2.c 4.1 94/02/15 GIE REL"; +#endif +#define PJ_LIB__ +# include <projects.h> +PROJ_HEAD(eck2, "Eckert II") "\n\tPCyl. Sph."; +#define FXC 0.46065886596178063902 +#define FYC 1.44720250911653531871 +#define C13 0.33333333333333333333 +#define ONEEPS 1.0000001 +FORWARD(s_forward); /* spheroid */ + xy.x = FXC * lp.lam * (xy.y = sqrt(4. - 3. * sin(fabs(lp.phi)))); + xy.y = FYC * (2. - xy.y); + if ( lp.phi < 0.) xy.y = -xy.y; + return (xy); +} +INVERSE(s_inverse); /* spheroid */ + lp.lam = xy.x / (FXC * ( lp.phi = 2. - fabs(xy.y) / FYC) ); + lp.phi = (4. - lp.phi * lp.phi) * C13; + if (fabs(lp.phi) >= 1.) { + if (fabs(lp.phi) > ONEEPS) I_ERROR + else + lp.phi = lp.phi < 0. ? -HALFPI : HALFPI; + } else + lp.phi = asin(lp.phi); + if (xy.y < 0) + lp.phi = -lp.phi; + return (lp); +} +FREEUP; if (P) pj_dalloc(P); } +ENTRY0(eck2); P->es = 0.; P->inv = s_inverse; P->fwd = s_forward; ENDENTRY(P) |