Fixed mpld3 exception. Revised availability checks for optional libs.

geoarray/baseclasses.py

@@ -2,6 +2,7 @@
 
 import os
 import warnings
+from importlib import util
 from collections import OrderedDict
 
 import numpy as np
@@ -1022,6 +1023,12 @@ class GeoArray(object):
         palette.set_over('1')
         palette.set_under('0')
 
+        # check availability of holoviews
+        if not util.find_spec('holoviews'):
+            warnings.warn("Interactive mode requires holoviews. Install it by running, e.g., "
+                          "'conda install --yes -c ioam bokeh holoviews'. Using non-interactive mode.")
+            interactive = False
+
         if interactive and image2plot.ndim == 3:
             import holoviews as hv
             from skimage.exposure import rescale_intensity
@@ -1079,23 +1086,27 @@ class GeoArray(object):
         :return:
         """
 
-        try:
-            from mpl_toolkits.basemap import Basemap
-        except ImportError:
-            warnings.warn('This function requires Basemap. You need to install basemap manually (see www./'
-                          'matplotlib.org/basemap) if you want to plot maps. It is not automatically installed.')
-            raise
-        try:
-            # noinspection PyUnresolvedReferences
+        if not util.find_spec('mpl_toolkits.basemap'):
+            raise ImportError('This function requires Basemap. You need to install basemap manually (see www./'
+                              'matplotlib.org/basemap) if you want to plot maps. It is not automatically installed.')
+
+        from mpl_toolkits.basemap import Basemap
+
+        mpld3_avl = util.find_spec('mpld3')
+        if not mpld3_avl:
+            warnings.warn('mpld3 is not available. Zooming disabled.')
+            zoomable = False
+
+        if zoomable:
             import mpld3
-            if zoomable:
-                mpld3.enable_notebook()
-            else:
+            mpld3.enable_notebook()
+        elif mpld3_avl:
+            import mpld3
+            # noinspection PyBroadException
+            try:
                 mpld3.disable_notebook()
-        except ImportError:
-            if zoomable:
-                zoomable = False
-                warnings.warn('mpld3 is not available. Zooming disabled.')
+            except Exception:
+                pass
 
         assert self.geotransform and tuple(self.geotransform) != (0, 1, 0, 0, 0, -1), \
             'A valid geotransform is needed for a map visualization. Got %s.' % list(self.geotransform)
@@ -1163,12 +1174,12 @@ class GeoArray(object):
     def show_map_utm(self, xlim=None, ylim=None, band=0, figsize=None, interpolation='none', cmap=None,
                      nodataVal=None, vmin=None, vmax=None, res_factor=None, return_map=False):
 
-        try:
-            from mpl_toolkits.basemap import Basemap
-        except ImportError:
-            warnings.warn('This function requires Basemap. You need to install basemap manually (see www./'
-                          'matplotlib.org/basemap) if you want to plot maps. It is not automatically installed.')
-            raise
+        if not util.find_spec('mpl_toolkits.basemap'):
+            raise ImportError('This function requires Basemap. You need to install basemap manually (see www./'
+                              'matplotlib.org/basemap) if you want to plot maps. It is not automatically installed.')
+
+        from mpl_toolkits.basemap import Basemap
+
         warnings.warn(UserWarning('This function is still under construction and may not work as expected!'))
         # TODO debug this function
 
@@ -1232,16 +1243,14 @@ class GeoArray(object):
         footprint of GeoArray.
         """
 
-        try:
-            import folium
-            import geojson
-        except ImportError:
-            folium, geojson = None, None
-        if not folium or not geojson:
+        if not util.find_spec('folium') or not util.find_spec('geojson'):
             raise ImportError(
                 "This method requires the libraries 'folium' and 'geojson'. They can be installed with "
                 "the shell command 'pip install folium geojson'.")
 
+        import folium
+        import geojson
+
         lonlatPoly = reproject_shapelyGeometry(self.footprint_poly, self.epsg, 4326)
 
         m = folium.Map(location=tuple(np.array(lonlatPoly.centroid.coords.xy).flatten())[::-1])