Merge pull request #335 from blaylockbk/accessors-to_180-and-to_360

add accessors to_180 and to_360

herbie/accessors.py

@@ -107,6 +107,19 @@ def center(self):
             self._center = (float(lon.mean()), float(lat.mean()))
         return self._center
 
+    def to_180(self):
+        """Wrap longitude coordinates as range [-180,180]."""
+        ds = self._obj
+        ds["longitude"] = (ds["longitude"] + 180) % 360 - 180
+        return ds
+
+    def to_360(self):
+        """Wrap longitude coordinates as range [0,360]."""
+        ds = self._obj
+        ds["longitude"] = (ds["longitude"] - 360) % 360
+        return ds
+
+
     @functools.cached_property
     def crs(self):
         """

tests/test_accessors.py

@@ -4,7 +4,7 @@
 """
 
 from herbie import Herbie
-
+import xarray as xr
 
 def test_crs():
     H = Herbie(
@@ -16,6 +16,15 @@ def test_crs():
     crs = ds.herbie.crs
     assert crs
 
+def test_to_180():
+    z = xr.Dataset({"longitude": [0, 90, 180, 270, 360]})
+    z = z.herbie.to_180()
+    assert all(z["longitude"] == [0, 90, -180, -90, 0])
+
+def test_to_360():
+    z = xr.Dataset({"longitude": [-90, -180, 0, 90, 180]})
+    z = z.herbie.to_360()
+    assert all(z["longitude"] == [270, 180, 0, 90, 180])
 
 def test_polygon():
     H = Herbie(