Implement tiles for Azure Maps

lib/cartopy/io/img_tiles.py

@@ -680,3 +680,37 @@ def _merge_tiles(tiles):
         img[img_slice] = tile_img
 
     return img, [min(xs), max(xs), min(ys), max(ys)], 'lower'
+
+
+class AzureMapsTiles(GoogleWTS):
+
+    def __init__(self, subscription_key, tileset_id="microsoft.imagery",
+                 api_version="2.0", desired_tile_form='RGB', cache=False):
+        """
+        Set up a new instance to retrieve tiles from Azure Maps.
+
+        Access to Azure Maps REST API requires an subscription key.
+        See https://docs.microsoft.com/en-us/azure/azure-maps/azure-maps-authentication#shared-key-authentication/ for details.
+
+        Parameters
+        ----------
+        subscription_key
+            A valid Azure Maps subscription key.
+        tileset_id
+            A tileset ID for a map. See
+            https://docs.microsoft.com/en-us/rest/api/maps/renderv2/getmaptilepreview#tilesetid for details.
+        api_version
+            API version to use. Defaults to 2.0 as recommended by Microsoft.
+
+        """
+        super().__init__(desired_tile_form=desired_tile_form, cache=cache)
+        self.subscription_key = subscription_key
+        self.tileset_id = tileset_id
+        self.api_version = api_version
+
+    def _image_url(self, tile):
+        url = ('https://atlas.microsoft.com/map/tile?'
+               'api-version={self.api_version}&tilesetId={self.tileset_id}'
+               '&x={x}&y={y}&zoom={z}&'
+               'subscription-key={self.subscription_key}')
+        return url.format(self=self, x=tile[0], y=tile[1], z=tile[2])

lib/cartopy/tests/test_img_tiles.py

@@ -290,6 +290,44 @@ def test_ordnance_survey_get_image():
     assert extent1 == extent2
 
 
+def test_azuremaps_tiles_api_url():
+    subscription_key = 'foo'
+    tileset_id = 'bar'
+    tile = [0, 1, 2]
+
+    exp_url = ('https://atlas.microsoft.com/map/tile?api-version=2.0'
+               '&tilesetId=bar&x=0&y=1&zoom=2&subscription-key=foo')
+
+    az_maps_sample = cimgt.AzureMapsTiles(subscription_key, tileset_id)
+    url_str = az_maps_sample._image_url(tile)
+    assert url_str == exp_url
+
+
+@pytest.mark.network
+def test_azuremaps_get_image():
+    # In order to test fetching map images from OS
+    # an API key needs to be provided
+    try:
+        api_key = os.environ['AZURE_MAPS_SUBSCRIPTION_KEY']
+    except KeyError:
+        pytest.skip('AZURE_MAPS_SUBSCRIPTION_KEY environment variable '
+                    'is unset.')
+
+    am1 = cimgt.AzureMapsTiles(api_key, tileset_id="microsoft.imagery")
+    am2 = cimgt.AzureMapsTiles(api_key, tileset_id="microsoft.base.road")
+
+    tile = (500, 300, 10)
+
+    img1, extent1, _ = am1.get_image(tile)
+    img2, extent2, _ = am2.get_image(tile)
+
+    # Different images for different layers
+    assert img1 != img2
+
+    # The extent is the same though
+    assert extent1 == extent2
+
+
 @pytest.mark.network
 @pytest.mark.parametrize('cache_dir', ["tmpdir", True, False])
 def test_cache(cache_dir, tmpdir):