Add antarctic_ice_shelves_polys to download (#7)

* Bump the version number to 0.2.3

* Add antarctic_ice_shelves_polys to download

This merge switches to using a python script to do the downloading.
This let us get the version number more easily from cartopy, as
well as add features that are not downloaded by default.

I have kind of cheated by downloading the python file we want and
then importing it as a module.  If a better way exists, I'm
eager to hear it!

bin/download_cartopy_data.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+import argparse
+import os
+import urllib.request
+import tempfile
+import cartopy
+from cartopy import config
+import sys
+
+
+def main(target_dir):
+    try:
+        os.makedirs(target_dir)
+    except OSError:
+        pass
+
+    version = cartopy.__version__
+
+    with tempfile.TemporaryDirectory() as tmpdirname:
+        target_dir = os.path.abspath(target_dir)
+        owd = os.getcwd()
+        os.chdir(tmpdirname)
+        urllib.request.urlretrieve(
+            'https://raw.githubusercontent.com/SciTools/cartopy/v{}/tools/feature_download.py'.format(version),
+            'feature_download.py')
+
+        file = open('__init__.py', 'w')
+        file.close()
+
+        sys.path.append(tmpdirname)
+
+        from feature_download import FEATURE_DEFN_GROUPS, download_features
+
+        # add Antarctic ice shelves
+        FEATURE_DEFN_GROUPS['physical'] = \
+            FEATURE_DEFN_GROUPS['physical'] + \
+            (('physical', 'antarctic_ice_shelves_polys', ('50m', '10m')),)
+
+        config['pre_existing_data_dir'] = target_dir
+        config['data_dir'] = target_dir
+        config['repo_data_dir'] = target_dir
+        download_features(
+            ['cultural-extra', 'cultural', 'gshhs', 'physical'], dry_run=False)
+        os.chdir(owd)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(
+        description='Download cartopy data for caching.')
+    parser.add_argument('--output', '-o', required=True,
+                        help='save datasets in the specified directory')
+    args = parser.parse_args()
+    main(args.output)

setup.py

@@ -1,12 +1,12 @@
 from setuptools import setup
 
 setup(name='cartopy_offlinedata',
-      version='0.2.2',
+      version='0.2.3',
       description='Add shared data path to cartopy config',
       url='https://github.com/willirath/cartopy_offlinedata',
       author='Willi Rath',
       author_email='[email protected]',
       license='MIT',
       packages=['cartopy_userconfig'],
-      scripts=['bin/download_cartopy_data.sh'],
+      scripts=['bin/download_cartopy_data.py'],
       zip_safe=False)