Better error message and exception for out-of-bound data

geoviews/tests/test_util.py

@@ -0,0 +1,20 @@
+import cartopy.crs as ccrs
+import pytest
+
+from geoviews.util import project_extents
+
+
+
+def test_outside_extents():
+ # extents outside bounds of map 32635, see https://epsg.io/32635
+ extents = (-2036817.4174174175, 577054.6546546547, -1801982.5825825825, 867745.3453453453)
+ dest_proj = ccrs.Mercator()
+ src_proj = ccrs.epsg(32635)
+
+ msg = (
+ "Could not project data from '.+?' projection to '.+?' projection\. "
+ "Ensure some data is inside the bounds \+\/\- the threshold of the CRS\. "
+ "For '.+?' this is \(xmin, xmax, ymin, ymax\) = \(.+?\)\."
+ )
+ with pytest.raises(ValueError, match=msg):
+ project_extents(extents, src_proj, dest_proj)

geoviews/util.py

@@ -100,13 +100,33 @@ def project_extents(extents, src_proj, dest_proj, tol=1e-6):
  try:
  geom_in_crs = dest_proj.project_geometry(geom_in_src_proj, src_proj)
  except ValueError:
- src_name =type(src_proj).__name__
- dest_name =type(dest_proj).__name__
- raise ValueError('Could not project data from %s projection '
- 'to %s projection. Ensure the coordinate '
- 'reference system (crs) matches your data '
- 'and the kdims.' %
- (src_name, dest_name))
+ src_name = type(src_proj).__name__
+ dest_name = type(dest_proj).__name__
+ raise ValueError(
+ f'Could not project data from {src_name} projection '
+ f'to {dest_name} projection. Ensure the coordinate '
+ 'reference system (CRS) matches your data and the kdims.'
+ ) from None
+ except IndexError:
+ # 'unknown' is returned when crs has no name.
+ src_type_name = type(src_proj).__name__
+ src_name = getattr(src_proj, "name", src_type_name)
+ src_name = src_type_name if src_name == "unknown" else src_name
+
+ dest_type_name = type(dest_proj).__name__
+ dest_name = getattr(dest_proj, "name", dest_type_name)
+ dest_name = dest_type_name if dest_name == "unknown" else dest_name
+
+ # Calculate the limit of the src_proj
+ b = np.array(src_proj.bounds)
+ t = src_proj.threshold * np.array([1, -1, 1, -1])
+ limit = np.round(b + t).astype(int)
+ raise ValueError(
+ f"Could not project data from '{src_name}' projection "
+ f"to '{dest_name}' projection. Ensure some data "
+ f"is inside the bounds +/- the threshold of the CRS. "
+ f"For '{src_name}' this is (xmin, xmax, ymin, ymax) = {tuple(limit)}."
+ ) from None
  else:
  geom_in_crs = boundary_poly.intersection(domain_in_src_proj)
  return geom_in_crs.bounds