Fix error in implementation of Inverse ellipsoidal orthographic proje…

…ction (oblique case) that cause convergence to sometimes fail (fixes #2844)
OSGeo · Sep 15, 2021 · 3bd64e8 · 3bd64e8
1 parent 47fb85b
commit 3bd64e8
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/src/projections/ortho.cpp b/src/projections/ortho.cpp
@@ -254,7 +254,7 @@ static PJ_LP ortho_e_inverse (PJ_XY xy, PJ *P) {           /* Ellipsoidal, inver
         const double J11 = -rho * sinphi * sinlam;
         const double J12 = nu * cosphi * coslam;
         const double J21 = rho * (cosphi * Q->cosph0 + sinphi * Q->sinph0 * coslam);
-        const double J22 = nu * Q->sinph0 * Q->cosph0 * sinlam;
+        const double J22 = nu * Q->sinph0 * cosphi * sinlam;
         const double D = J11 * J22 - J12 * J21;
         const double dx = xy.x - xy_new.x;
         const double dy = xy.y - xy_new.y;

diff --git a/test/gie/builtins.gie b/test/gie/builtins.gie
@@ -4531,6 +4531,16 @@ tolerance   0.1 mm
 accept      0               -6343600
 expect      0               -59.966377950099655436
 
+-------------------------------------------------------------------------------
+# Oblique
+# Test case from https://github.com/OSGeo/PROJ/issues/2844
+-------------------------------------------------------------------------------
+operation   +proj=ortho +ellps=WGS84 +lon_0=23.0 +lat_0=37.0
+tolerance   0.1 mm
+accept      120.0           84.0
+expect      663929.0678     5118338.2423
+roundtrip   1
+
 
 -------------------------------------------------------------------------------
 # Equatorial