Add WRF lon-lat projection (#224)

* add map_proj = 6 (Lat-lon) (#221) * add test and remove geogrid simulator Co-authored-by: Matthias Demuzere <mdemuzere@gmail.com>
fmaussion · Sep 6, 2022 · b9e353c · b9e353c
1 parent c42d3e5
commit b9e353c
Show file tree

Hide file tree

Showing 3 changed files with 28 additions and 6 deletions.
diff --git a/salem/__init__.py b/salem/__init__.py
@@ -46,7 +46,7 @@ def _lazy_property(self):
 if not path.exists(download_dir):
     makedirs(download_dir)
 
-sample_data_gh_commit = 'd975954c9bbd6505b2e7a2e06aa42f4696a0ad6b'
+sample_data_gh_commit = '57e6d694aa470b967336f5ca2d4fc743c5c8efd6'
 sample_data_dir = path.join(cache_dir, 'salem-sample-data-' +
                             sample_data_gh_commit)
 

diff --git a/salem/sio.py b/salem/sio.py
@@ -140,6 +140,8 @@ def _wrf_grid_from_dataset(ds):
         if ds.PROJ_NAME in ['Lambert Conformal Conic',
                             'WRF Lambert Conformal']:
             proj_id = 1
+        elif ds.PROJ_NAME in ['lat-lon']:
+            proj_id = 6
         else:
             proj_id = 99  # pragma: no cover
     else:
@@ -172,6 +174,12 @@ def _wrf_grid_from_dataset(ds):
              '+lon_0={center_lon} ' \
              '+x_0=0 +y_0=0 +a=6370000 +b=6370000'
         p4 = p4.format(**pargs)
+    elif proj_id == 6:
+        # Lat-long
+        p4 = '+proj=eqc ' \
+             '+lon_0={lon_0} ' \
+             '+x_0=0 +y_0=0 +a=6370000 +b=6370000'
+        p4 = p4.format(**pargs)
     else:
         raise NotImplementedError('WRF proj not implemented yet: '
                                   '{}'.format(proj_id))
@@ -515,11 +523,6 @@ def roi(self, ds=None, **kwargs):
             kwargs.setdefault('grid', grid)
 
         mask = self.grid.region_of_interest(**kwargs)
-        # coords = {self.y_dim: self._obj[self.y_dim].values,
-        #           self.x_dim: self._obj[self.x_dim].values}
-        # mask = xr.DataArray(mask, coords=coords,
-        #                     dims=(self.y_dim, self.x_dim))
-
         out = self._obj.where(mask, other=other)
 
         # keep attrs and encoding

diff --git a/salem/tests/test_datasets.py b/salem/tests/test_datasets.py
@@ -370,6 +370,25 @@ def test_wrf_polar(self):
         np.testing.assert_allclose(reflon, mylon, atol=1e-4)
         np.testing.assert_allclose(reflat, mylat, atol=1e-4)
 
+    @requires_geopandas
+    def test_wrf_latlon(self):
+
+        d = GeoNetcdf(get_demo_file('geo_em.d01_lon-lat.nc'))
+        mylon, mylat = d.grid.ll_coordinates
+        reflon = np.squeeze(d.get_vardata('XLONG_M'))
+        reflat = np.squeeze(d.get_vardata('XLAT_M'))
+
+        np.testing.assert_allclose(reflon, mylon, atol=1e-4)
+        np.testing.assert_allclose(reflat, mylat, atol=1e-4)
+
+        d = GeoNetcdf(get_demo_file('geo_em.d04_lon-lat.nc'))
+        mylon, mylat = d.grid.ll_coordinates
+        reflon = np.squeeze(d.get_vardata('XLONG_M'))
+        reflat = np.squeeze(d.get_vardata('XLAT_M'))
+
+        np.testing.assert_allclose(reflon, mylon, atol=1e-4)
+        np.testing.assert_allclose(reflat, mylat, atol=1e-4)
+
     def test_longtime(self):
         """There was a bug with time"""