Fix handling wkt strings and add pyproj.CRS support

hvplot/tests/testutil.py

@@ -217,6 +217,14 @@ def test_proj_to_cartopy(self):
 
         assert isinstance(crs, self.ccrs.CRS)
 
+    def test_proj_to_cartopy_wkt_string(self):
+        from ..util import proj_to_cartopy
+        crs = proj_to_cartopy('GEOGCRS["unnamed",BASEGEOGCRS["unknown",DATUM["unknown",ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1,ID["EPSG",9001]]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8901]]],DERIVINGCONVERSION["unknown",METHOD["PROJ ob_tran o_proj=latlon"],PARAMETER["o_lon_p",0,ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]],PARAMETER["o_lat_p",37.5,ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]],PARAMETER["lon_0",357.5,ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]]],CS[ellipsoidal,2],AXIS["longitude",east,ORDER[1],ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]],AXIS["latitude",north,ORDER[2],ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]]]')  # noqa: E501
+
+        assert isinstance(crs, self.ccrs.RotatedPole)
+        assert crs.proj4_params["lon_0"] == 357.5
+        assert crs.proj4_params["o_lat_p"] == 37.5
+
 
 class TestDynamicArgs(TestCase):
 

hvplot/util.py

@@ -79,8 +79,11 @@ class Dummy:
         out = pyproj.Proj(crs.to_wkt(), preserve_units=True)
     elif isinstance(crs, dict) or isinstance(crs, str):
         if isinstance(crs, str):
-            # quick fix for https://github.com/pyproj4/pyproj/issues/345
-            crs = crs.replace(' ', '').replace('+', ' +')
+            try:
+                crs = pyproj.CRS.from_wkt(crs)
+            except RuntimeError:
+                # quick fix for https://github.com/pyproj4/pyproj/issues/345
+                crs = crs.replace(' ', '').replace('+', ' +')
         try:
             out = pyproj.Proj(crs, preserve_units=True)
         except RuntimeError:
@@ -124,10 +127,10 @@ def proj_to_cartopy(proj):
     except ImportError:
         has_gdal = False
 
-    proj = check_crs(proj)
-
-    if proj_is_latlong(proj):
-        return ccrs.PlateCarree()
+    input_proj = proj
+    proj = check_crs(input_proj)
+    if proj is None:
+        raise ValueError(f"Invalid proj projection {input_proj!r}")
 
     srs = proj.srs
     if has_gdal:
@@ -167,19 +170,23 @@ def proj_to_cartopy(proj):
         except:
             pass
         if k == 'proj':
-            if v == 'tmerc':
+            if v == "longlat":
+                cl = ccrs.PlateCarree
+            elif v == 'tmerc':
                 cl = ccrs.TransverseMercator
                 kw_proj['approx'] = True
-            if v == 'lcc':
+            elif v == 'lcc':
                 cl = ccrs.LambertConformal
-            if v == 'merc':
+            elif v == 'merc':
                 cl = ccrs.Mercator
-            if v == 'utm':
+            elif v == 'utm':
                 cl = ccrs.UTM
-            if v == 'stere':
+            elif v == 'stere':
                 cl = ccrs.Stereographic
-            if v == 'ob_tran':
+            elif v == 'ob_tran':
                 cl = ccrs.RotatedPole
+            else:
+                raise NotImplementedError('Unknown projection {}'.format(v))
         if k in km_proj:
             if k == 'zone':
                 v = int(v)
@@ -228,7 +235,8 @@ def process_crs(crs):
       1. EPSG codes:   Defined as string of the form "EPSG: {code}" or an integer
       2. proj.4 string: Defined as string of the form "{proj.4 string}"
       3. cartopy.crs.CRS instance
-      4. None defaults to crs.PlateCaree
+      4. WKT string:    Defined as string of the form "{WKT string}"
+      5. None defaults to crs.PlateCaree
     """
     missing = []
     try:
@@ -252,13 +260,12 @@ def process_crs(crs):
     errors = []
     if isinstance(crs, str) and crs.lower().startswith('epsg'):
         try:
-            crs = crs[5:].lstrip().rstrip()
-            return ccrs.epsg(crs)
+            crs = pyproj.CRS.from_epsg(crs).to_wkt()
         except Exception as e:
             errors.append(e)
     if isinstance(crs, int):
         try:
-            return ccrs.epsg(crs)
+            crs = pyproj.CRS.from_epsg(crs).to_wkt()
         except Exception as e:
             crs = str(crs)
             errors.append(e)
@@ -270,7 +277,10 @@ def process_crs(crs):
     if isinstance(crs, ccrs.CRS):
         return crs
 
-    raise ValueError("Projection must be defined as a EPSG code, proj4 string, cartopy CRS or pyproj.Proj.") from Exception(*errors)
+    raise ValueError(
+        "Projection must be defined as a EPSG code, proj4 string, "
+        "WKT string, cartopy CRS, or pyproj.Proj."
+    ) from Exception(*errors)
 
 
 def is_list_like(obj):