Add return_back_azimuth: bool to _inv_or_fwd_intermediate

pyproj4 · Dec 19, 2022 · 3f1de5b · 3f1de5b
1 parent b0b0d4f
commit 3f1de5b
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diff --git a/pyproj/_geod.pyi b/pyproj/_geod.pyi
@@ -55,6 +55,7 @@ class Geod:
         out_lons: Any,
         out_lats: Any,
         out_azis: Any,
+        return_back_azimuth: bool,
     ) -> GeodIntermediateReturn: ...
     def _line_length(self, lons: Any, lats: Any, radians: bool = False) -> float: ...
     def _polygon_area_perimeter(

diff --git a/pyproj/_geod.pyx b/pyproj/_geod.pyx
@@ -244,6 +244,7 @@ cdef class Geod:
         object out_lons,
         object out_lats,
         object out_azis,
+        bint return_back_azimuth,
     ) -> GeodIntermediateReturn:
         """
         .. versionadded:: 3.1.0
@@ -335,6 +336,11 @@ cdef class Geod:
                 lats_buff.data[iii] = plat2
                 lons_buff.data[iii] = plon2
                 if store_az:
+                    # by default (return_back_azimuth=True),
+                    # forward azimuth needs to be flipped 180 degrees
+                    # to match the (back azimuth) output of PROJ geod utilities.
+                    if return_back_azimuth:
+                        pazi2 =_reverse_azimuth(pazi2, factor=180)
                     azis_buff.data[iii] = pazi2
 
         return GeodIntermediateReturn(