From c08ab85a6910f33ccc5ab15855751af44c185c16 Mon Sep 17 00:00:00 2001
From: Greg Lucas <greg.m.lucas@gmail.com>
Date: Tue, 25 Jan 2022 21:48:52 -0700
Subject: [PATCH] FIX: Allow values less than -180 to be wrapped too

This adds a check for values less than -180, effectively clipping
all PlateCarree values to be between -180 and 180 after transforms.
---
 lib/cartopy/crs.py            |  2 +-
 lib/cartopy/tests/test_crs.py | 11 +++++++++++
 lib/cartopy/trace.pyx         |  2 +-
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/lib/cartopy/crs.py b/lib/cartopy/crs.py
index d7abbff5c..702c80036 100644
--- a/lib/cartopy/crs.py
+++ b/lib/cartopy/crs.py
@@ -402,7 +402,7 @@ def transform_points(self, src_crs, x, y, z=None, trap=False):
                     self.is_geodetic()):
                 # convert from [0,360] to [-180,180]
                 x = np.array(x, copy=True)
-                to_180 = x > 180
+                to_180 = (x > 180) | (x < -180)
                 x[to_180] = (((x[to_180] + 180) % 360) - 180)
             try:
                 result[:, 0], result[:, 1], result[:, 2] = \
diff --git a/lib/cartopy/tests/test_crs.py b/lib/cartopy/tests/test_crs.py
index 977494f58..1c737e05d 100644
--- a/lib/cartopy/tests/test_crs.py
+++ b/lib/cartopy/tests/test_crs.py
@@ -173,6 +173,17 @@ def test_transform_points_xyz(self):
         assert_arr_almost_eq(glon, soly)
         assert_arr_almost_eq(galt, solz)
 
+    def test_transform_points_180(self):
+        # Test that values less than -180 and more than 180
+        # get mapped to the -180, 180 interval
+        x = np.array([-190, 190])
+        y = np.array([0, 0])
+
+        proj = ccrs.PlateCarree()
+
+        res = proj.transform_points(x=x, y=y, src_crs=proj)
+        assert_array_equal(res[..., :2], [[170, 0], [-170, 0]])
+
     def test_globe(self):
         # Ensure the globe affects output.
         rugby_globe = ccrs.Globe(semimajor_axis=9000000,
diff --git a/lib/cartopy/trace.pyx b/lib/cartopy/trace.pyx
index 82ea1a431..2942d14c7 100644
--- a/lib/cartopy/trace.pyx
+++ b/lib/cartopy/trace.pyx
@@ -231,7 +231,7 @@ cdef class Interpolator:
             else:
                 raise
 
-        if self.to_180 and xx > 180 and xx != HUGE_VAL:
+        if self.to_180 and (xx > 180 or xx < -180) and xx != HUGE_VAL:
             xx = (((xx + 180) % 360) - 180)
 
         dest_xy.x = xx * self.dest_scale