REF: Reduce pyproj.CRS internal usage for speed (#242)

docs/history.rst

@@ -3,6 +3,7 @@ History
 
 Latest
 ------
+- REF: Reduce pyproj.CRS internal usage for speed (issue #241)
 
 0.2.0
 ------

rioxarray/_io.py

@@ -291,7 +291,7 @@ def _parse_tags(tags):
     2: np.char,  # NC_CHAR
     3: np.short,  # NC_SHORT
     4: np.int_,  # NC_INT, NC_LONG
-    5: np.float,  # NC_FLOAT
+    5: float,  # NC_FLOAT
     6: np.double,  # NC_DOUBLE
     7: np.ubyte,  # NC_UBYTE
     8: np.ushort,  # NC_USHORT

rioxarray/crs.py

@@ -5,11 +5,15 @@
 from distutils.version import LooseVersion
 
 import rasterio
+import rasterio.crs
 from pyproj import CRS
+from rasterio.errors import CRSError
 
 
-def crs_to_wkt(crs_input):
+def crs_from_user_input(crs_input):
     """
+    Return a rasterio.crs.CRS from user input.
+
     This is to deal with change in rasterio.crs.CRS
     as well as to assist in the transition between GDAL 2/3.
 
@@ -20,16 +24,22 @@ def crs_to_wkt(crs_input):
 
     Returns
     -------
-    str: WKT string.
+    rasterio.crs.CRS
 
     """
+    if isinstance(crs_input, rasterio.crs.CRS):
+        return crs_input
     try:
-        # rasterio.crs.CRS <1.0.14 and
         # old versions of opendatacube CRS
         crs_input = crs_input.wkt
     except AttributeError:
         pass
+    try:
+        return rasterio.crs.CRS.from_user_input(crs_input)
+    except CRSError:
+        pass
+    # use pyproj for edge cases
     crs = CRS.from_user_input(crs_input)
     if LooseVersion(rasterio.__gdal_version__) > LooseVersion("3.0.0"):
-        return crs.to_wkt()
-    return crs.to_wkt("WKT1_GDAL")
+        return rasterio.crs.CRS.from_wkt(crs.to_wkt())
+    return rasterio.crs.CRS.from_wkt(crs.to_wkt("WKT1_GDAL"))

rioxarray/raster_array.py

@@ -19,12 +19,11 @@
 import rasterio.mask
 import rasterio.warp
 import xarray
-from rasterio.crs import CRS
 from rasterio.enums import Resampling
 from rasterio.features import geometry_mask
 from scipy.interpolate import griddata
 
-from rioxarray.crs import crs_to_wkt
+from rioxarray.crs import crs_from_user_input
 from rioxarray.exceptions import (
     MissingCRS,
     NoDataInBounds,
@@ -430,9 +429,8 @@ def reproject_match(self, match_data_array, resampling=Resampling.nearest):
             Contains the data from the src_data_array, reprojected to match
             match_data_array.
         """
-        dst_crs = crs_to_wkt(match_data_array.rio.crs)
         return self.reproject(
-            dst_crs,
+            match_data_array.rio.crs,
             transform=match_data_array.rio.transform(recalc=True),
             shape=match_data_array.rio.shape,
             resampling=resampling,
@@ -697,7 +695,7 @@ def clip(
                 "CRS not found. Please set the CRS with 'rio.write_crs()'."
                 f"{_get_data_var_message(self._obj)}"
             )
-        crs = CRS.from_wkt(crs_to_wkt(crs)) if crs is not None else self.crs
+        crs = crs_from_user_input(crs) if crs is not None else self.crs
         if self.crs != crs:
             if LooseVersion(rasterio.__version__) >= LooseVersion("1.2"):
                 geometries = rasterio.warp.transform_geom(crs, self.crs, geometries)

rioxarray/rioxarray.py

@@ -12,7 +12,7 @@
 from affine import Affine
 from rasterio.crs import CRS
 
-from rioxarray.crs import crs_to_wkt
+from rioxarray.crs import crs_from_user_input
 from rioxarray.exceptions import (
     DimensionError,
     DimensionMissingCoordinateError,
@@ -151,6 +151,18 @@ def crs(self):
         if self._crs is not None:
             return None if self._crs is False else self._crs
 
+        # look in wkt attributes to avoid using
+        # pyproj CRS if possible for performance
+        for crs_attr in ("spatial_ref", "crs_wkt"):
+            try:
+                self.set_crs(
+                    self._obj.coords[self.grid_mapping].attrs[crs_attr],
+                    inplace=True,
+                )
+                return self._crs
+            except KeyError:
+                pass
+
         # look in grid_mapping
         try:
             self.set_crs(
@@ -207,7 +219,7 @@ def set_crs(self, input_crs, inplace=True):
         :obj:`xarray.Dataset` | :obj:`xarray.DataArray`:
             Dataset with crs attribute.
         """
-        crs = CRS.from_wkt(crs_to_wkt(input_crs))
+        crs = crs_from_user_input(input_crs)
         obj = self._get_obj(inplace=inplace)
         obj.rio._crs = crs
         return obj
@@ -316,7 +328,7 @@ def write_crs(self, input_crs=None, grid_mapping_name=None, inplace=False):
         data_obj.coords[grid_mapping_name] = xarray.Variable((), 0)
         grid_map_attrs = pyproj.CRS.from_user_input(data_obj.rio.crs).to_cf()
         # spatial_ref is for compatibility with GDAL
-        crs_wkt = crs_to_wkt(data_obj.rio.crs)
+        crs_wkt = data_obj.rio.crs.to_wkt()
         grid_map_attrs["spatial_ref"] = crs_wkt
         grid_map_attrs["crs_wkt"] = crs_wkt
         if transform is not None: