Replaced 'importlib.util.find_spec' with 'pkgutil.find_loader' to ensure...

Replaced 'importlib.util.find_spec' with 'pkgutil.find_loader' to ensure Python 2.7 compatibility. Added some type hints.

geoarray/baseclasses.py

@@ -2,9 +2,10 @@
 
 import os
 import warnings
-from importlib import util
+from pkgutil import find_loader
 from collections import OrderedDict
 from copy import deepcopy
+from typing import Union  # noqa F401
 
 import numpy as np
 from matplotlib import pyplot as plt
@@ -53,7 +54,7 @@ __author__ = 'Daniel Scheffler'
 class GeoArray(object):
     def __init__(self, path_or_array, geotransform=None, projection=None, bandnames=None, nodata=None, progress=True,
                  q=False):
-        # type: (any, tuple, str, list, float, bool, bool) -> None
+        # type: (Union[str, np.ndarray], tuple, str, list, float, bool, bool) -> None
         """This class creates a fast Python interface for geodata - either on disk or in memory. It can be instanced with
         a file path or with a numpy array and the corresponding geoinformation. Instances can always be indexed like
         normal numpy arrays, no matter if GeoArray has been instanced from file or from an in-memory array. GeoArray
@@ -254,6 +255,7 @@ class GeoArray(object):
 
     @geotransform.setter
     def geotransform(self, gt):
+        # type: (Union[list, tuple]) -> None
         assert isinstance(gt, (list, tuple)) and len(gt) == 6,\
             'geotransform must be a list with 6 numbers. Got %s.' % str(gt)
 
@@ -303,6 +305,7 @@ class GeoArray(object):
 
     @projection.setter
     def projection(self, prj):
+        # type: (str) -> None
         if self.filePath:
             assert self.projection is None or prj_equal(self.projection, prj), \
                 "Cannot set %s.projection to the given value because it does not match the projection from the file " \
@@ -320,6 +323,7 @@ class GeoArray(object):
 
     @epsg.setter
     def epsg(self, epsg_code):
+        # type: (int) -> None
         self.projection = EPSG2WKT(epsg_code)
 
     @property
@@ -354,6 +358,7 @@ class GeoArray(object):
 
     @nodata.setter
     def nodata(self, value):
+        # type: (Union[int, None]) -> None
         self._nodata = value
 
     @property
@@ -1110,7 +1115,7 @@ class GeoArray(object):
         palette.set_under('0')
 
         # check availability of holoviews
-        if not util.find_spec('holoviews'):
+        if not find_loader('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
@@ -1177,13 +1182,13 @@ class GeoArray(object):
         :return:
         """
 
-        if not util.find_spec('mpl_toolkits.basemap'):
+        if not find_loader('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')
+        mpld3_avl = find_loader('mpld3')
         if not mpld3_avl:
             warnings.warn('mpld3 is not available. Zooming disabled.')
             zoomable = False
@@ -1265,7 +1270,7 @@ 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):
 
-        if not util.find_spec('mpl_toolkits.basemap'):
+        if not find_loader('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.')
 
@@ -1334,7 +1339,7 @@ class GeoArray(object):
         footprint of GeoArray.
         """
 
-        if not util.find_spec('folium') or not util.find_spec('geojson'):
+        if not find_loader('folium') or not find_loader('geojson'):
             raise ImportError(
                 "This method requires the libraries 'folium' and 'geojson'. They can be installed with "
                 "the shell command 'pip install folium geojson'.")

setup.py

@@ -3,7 +3,8 @@
 
 from setuptools import setup, find_packages
 import warnings
-from importlib import util
+from pkgutil import find_loader
+
 
 with open('README.rst') as readme_file:
     readme = readme_file.read()
@@ -61,11 +62,11 @@ setup(
 
 
 # check for holoviews
-if not util.find_spec('holoviews'):
+if not find_loader('holoviews'):
     warnings.warn('You need to install holoviews manually (see www.holoviews.org) if you want to use interactive '
                   'plotting. It is not automatically installed.')
 
 # check for basemap
-if not util.find_spec('mpl_toolkits.basemap'):
+if not find_loader('mpl_toolkits.basemap'):
     warnings.warn('You need to install basemap manually (see www./matplotlib.org/basemap) if you want to plot maps. '
                   'It is not automatically installed.')

tests/test_geoarray.py

@@ -34,7 +34,7 @@ import unittest
 from unittest import TestLoader
 import matplotlib
 from typing import Iterable
-from importlib import util
+from pkgutil import find_loader
 import tempfile
 
 # Imports regarding the created python module.
@@ -625,7 +625,7 @@ class Test_GeoarrayFunctions(unittest.TestCase):
         self.testtiff.show()
         # self.testtiff.show(interactive=True) # only works if test is started with ipython.
 
-        if util.find_spec('mpl_toolkits.basemap'):
+        if find_loader('mpl_toolkits.basemap'):
             self.testtiff.show_map()
             self.testtiff.show_map_utm()  # Function still under construction.
         self.testtiff.show_histogram()