From b38d0143a65fff72635b95a61ed6c4c41802889e Mon Sep 17 00:00:00 2001 From: Even Rouault Date: Wed, 11 Nov 2020 23:56:58 +0100 Subject: Polar stereographic at pole: make it return (0,0) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Due to the improved accuracy of pj_tsfn(), it no longer returns 0 when phi=90° due to the conversion in radians. Some GDAL tests are very sensitive to the pole transforming to (0,0) exactly, so add a special case for that. master only --- src/projections/stere.cpp | 5 ++++- test/gie/builtins.gie | 26 ++++++++++++++++++++++++++ 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/src/projections/stere.cpp b/src/projections/stere.cpp index abc4aa13..3fff722d 100644 --- a/src/projections/stere.cpp +++ b/src/projections/stere.cpp @@ -86,7 +86,10 @@ static PJ_XY stere_e_forward (PJ_LP lp, PJ *P) { /* Ellipsoidal, forwar sinphi = -sinphi; /*-fallthrough*/ case N_POLE: - xy.x = Q->akm1 * pj_tsfn (lp.phi, sinphi, P->e); + if( fabs(lp.phi - M_HALFPI) < 1e-15 ) + xy.x = 0; + else + xy.x = Q->akm1 * pj_tsfn (lp.phi, sinphi, P->e); xy.y = - xy.x * coslam; break; } diff --git a/test/gie/builtins.gie b/test/gie/builtins.gie index def30206..add5d925 100644 --- a/test/gie/builtins.gie +++ b/test/gie/builtins.gie @@ -5419,6 +5419,32 @@ accept -200 -100 expect -0.001790493 -0.000895247 +------------------------------------------------------------------------------- +operation +proj=stere +ellps=GRS80 +lat_0=90 +lat_ts=70 +------------------------------------------------------------------------------- +tolerance 1e-15m +accept 0 90 +expect 0 0 +roundtrip 1 + +tolerance 0.1 mm +accept 20 70 +expect 748315.3282 -2055979.4669 +roundtrip 1 + +------------------------------------------------------------------------------- +operation +proj=stere +ellps=GRS80 +lat_0=-90 +lat_ts=-70 +------------------------------------------------------------------------------- +tolerance 1e-15m +accept 0 -90 +expect 0 0 +roundtrip 1 + +tolerance 0.1 mm +accept 20 -70 +expect 748315.3282 2055979.4669 +roundtrip 1 + =============================================================================== # Oblique Stereographic Alternative # Azimuthal, Sph&Ell -- cgit v1.2.3