Fix logic for no geoviews explorer (#1451)

Co-authored-by: maximlt <mliquet@anaconda.com>

Author: ahuang11

hvplot/converter.py

@@ -76,6 +76,7 @@
     process_derived_datetime_pandas,
     _convert_col_names_to_str,
     import_datashader,
+    import_geoviews,
     is_mpl_cmap,
 )
 from .utilities import hvplot_extension
@@ -647,6 +648,10 @@ def __init__(
 
         self.dynamic = dynamic
         self.geo = any([geo, crs, global_extent, projection, project, coastline, features])
+        # Try importing geoviews if geo-features requested
+        if self.geo or self.datatype == 'geopandas':
+            import_geoviews()
+
         self.crs = self._process_crs(data, crs) if self.geo else None
         self.output_projection = self.crs
         self.project = project
@@ -656,17 +661,6 @@ def __init__(
         self.tiles_opts = tiles_opts or {}
         self.sort_date = sort_date
 
-        # Import geoviews if geo-features requested
-        if self.geo or self.datatype == 'geopandas':
-            try:
-                import geoviews  # noqa
-            except ImportError:
-                raise ImportError(
-                    'In order to use geo-related features '
-                    'the geoviews library must be available. '
-                    'It can be installed with:\n  conda '
-                    'install geoviews'
-                )
         if self.geo:
             if self.kind not in self._geo_types:
                 param.main.param.warning(

hvplot/tests/testui.py

@@ -1,5 +1,6 @@
 import re
 from textwrap import dedent
+from unittest.mock import patch
 
 import numpy as np
 import holoviews as hv
@@ -415,3 +416,9 @@ def test_max_rows_sample():
     ui = hvplot.explorer(df, x='x', y='y', by=['#'], kind='scatter')
     assert len(ui._data) == MAX_ROWS
     assert not ui._data.equals(df.head(MAX_ROWS))
+
+
+def test_explorer_geo_no_import_error_when_false():
+    da = ds_air_temperature['air'].isel(time=0)
+    with patch('hvplot.util.import_geoviews', return_value=None):
+        assert hvplot.explorer(da, x='lon', y='lat', geo=False)

hvplot/tests/testutil.py

@@ -18,6 +18,7 @@
 
 from hvplot.util import (
     check_crs,
+    import_geoviews,
     is_list_like,
     process_crs,
     process_xarray,
@@ -383,3 +384,8 @@ def test_is_geodataframe_spatialpandas_dask():
 def test_is_geodataframe_classic_dataframe():
     df = pd.DataFrame({'geometry': [None, None], 'name': ['A', 'B']})
     assert not is_geodataframe(df)
+
+
+@pytest.mark.geo
+def test_geoviews_is_available():
+    assert import_geoviews()

hvplot/ui.py

@@ -10,7 +10,7 @@
 
 from .converter import HoloViewsConverter as _hvConverter
 from .plotting import hvPlot as _hvPlot
-from .util import is_geodataframe, is_xarray, instantiate_crs_str
+from .util import is_geodataframe, is_xarray, instantiate_crs_str, import_geoviews
 
 # Defaults
 KINDS = {
@@ -361,17 +361,10 @@ class Geographic(Controls):
     _widgets_kwargs = {'geo': {'type': pn.widgets.Toggle}}
 
     def __init__(self, data, **params):
-        gv_available = False
-        try:
-            import geoviews  # noqa
-
-            gv_available = True
-        except ImportError:
-            pass
-
         geo_params = GEO_KEYS + ['geo']
-        if not gv_available and any(p in params for p in geo_params):
-            raise ImportError('GeoViews must be installed to enable the geographic options.')
+        gv_available = None
+        if any(params.get(p) for p in geo_params):
+            gv_available = import_geoviews()
         super().__init__(data, **params)
         if not gv_available:
             for p in geo_params:

hvplot/util.py

@@ -729,6 +729,18 @@ def import_datashader():
     return datashader
 
 
+def import_geoviews():
+    geoviews = None
+    try:
+        import geoviews
+    except ModuleNotFoundError:
+        raise ModuleNotFoundError(
+            'The `geoviews` package must be installed in order to use '
+            'geographic features. Install it with pip or conda.'
+        ) from None
+    return geoviews
+
+
 def relabel(hv_obj, **kwargs):
     """Conditionally relabel a HoloViews object"""
     if kwargs: