diff --git a/sbapp/mapview/downloader.py b/sbapp/mapview/downloader.py
index f219ff6..ce3a94f 100644
--- a/sbapp/mapview/downloader.py
+++ b/sbapp/mapview/downloader.py
@@ -89,6 +89,21 @@ class Downloader:
         response.raise_for_status()
         return callback, (url, response)
 
+    def __to_quad(self, x, y, z):
+        quad_key = []
+        i = z
+        while i > 0:
+            digit = 0
+            mask = 1 << (i-1)
+            if (x & mask) != 0:
+                digit += 1
+            if (y & mask) != 0:
+                digit += 2
+            quad_key.append(str(digit))
+
+            i -= 1
+        return "".join(quad_key)
+
     def _load_tile(self, tile):
         if tile.state == "done":
             return
@@ -97,9 +112,16 @@ class Downloader:
             # Logger.debug("Downloader: use cache {}".format(cache_fn))
             return tile.set_source, (cache_fn,)
         tile_y = tile.map_source.get_row_count(tile.zoom) - tile.tile_y - 1
-        uri = tile.map_source.url.format(
-            z=tile.zoom, x=tile.tile_x, y=tile_y, s=choice(tile.map_source.subdomains)
-        )
+
+        if tile.map_source.quad_key:
+            uri = tile.map_source.url.format(
+                q=self.__to_quad(tile.tile_x,tile_y,tile.zoom), s=choice(tile.map_source.subdomains)
+            )
+        else:
+            uri = tile.map_source.url.format(
+                z=tile.zoom, x=tile.tile_x, y=tile_y, s=choice(tile.map_source.subdomains)
+            )
+
         # Logger.debug("Downloader: download(tile) {}".format(uri))
         response = requests.get(uri, headers={'User-agent': USER_AGENT}, timeout=5)
         try:
diff --git a/sbapp/mapview/source.py b/sbapp/mapview/source.py
index 3c9b203..db1e1c1 100644
--- a/sbapp/mapview/source.py
+++ b/sbapp/mapview/source.py
@@ -23,7 +23,7 @@ class MapSource:
     """
 
     attribution_osm = 'Maps & Data © [i][ref=http://www.osm.org/copyright]OpenStreetMap contributors[/ref][/i]'
-    attribution_thunderforest = 'Maps © [i][ref=http://www.thunderforest.com]Thunderforest[/ref][/i], Data © [i][ref=http://www.osm.org/copyright]OpenStreetMap contributors[/ref][/i]'
+    attribution_ve = 'Maps © [i][ref=http://www.virtualearth.net]VirtualEarth[/ref][/i]'
 
     # list of available providers
     # cache_key: (is_overlay, minzoom, maxzoom, url, attribution)
@@ -35,6 +35,13 @@ class MapSource:
             "http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png",
             attribution_osm,
         ),
+        "ve": (
+            0,
+            0,
+            19,
+            "http://ecn.t3.tiles.virtualearth.net/tiles/a{q}.jpeg?g=1",
+            attribution_ve,
+        ),
         "osm-hot": (
             0,
             0,
@@ -42,63 +49,6 @@ class MapSource:
             "http://{s}.tile.openstreetmap.fr/hot/{z}/{x}/{y}.png",
             "",
         ),
-        "osm-de": (
-            0,
-            0,
-            18,
-            "http://{s}.tile.openstreetmap.de/tiles/osmde/{z}/{x}/{y}.png",
-            "Tiles @ OSM DE",
-        ),
-        "osm-fr": (
-            0,
-            0,
-            20,
-            "http://{s}.tile.openstreetmap.fr/osmfr/{z}/{x}/{y}.png",
-            "Tiles @ OSM France",
-        ),
-        "cyclemap": (
-            0,
-            0,
-            17,
-            "http://{s}.tile.opencyclemap.org/cycle/{z}/{x}/{y}.png",
-            "Tiles @ Andy Allan",
-        ),
-        "thunderforest-cycle": (
-            0,
-            0,
-            19,
-            "http://{s}.tile.thunderforest.com/cycle/{z}/{x}/{y}.png",
-            attribution_thunderforest,
-        ),
-        "thunderforest-transport": (
-            0,
-            0,
-            19,
-            "http://{s}.tile.thunderforest.com/transport/{z}/{x}/{y}.png",
-            attribution_thunderforest,
-        ),
-        "thunderforest-landscape": (
-            0,
-            0,
-            19,
-            "http://{s}.tile.thunderforest.com/landscape/{z}/{x}/{y}.png",
-            attribution_thunderforest,
-        ),
-        "thunderforest-outdoors": (
-            0,
-            0,
-            19,
-            "http://{s}.tile.thunderforest.com/outdoors/{z}/{x}/{y}.png",
-            attribution_thunderforest,
-        ),
-        # no longer available
-        # "mapquest-osm": (0, 0, 19, "http://otile{s}.mqcdn.com/tiles/1.0.0/map/{z}/{x}/{y}.jpeg", "Tiles Courtesy of Mapquest", {"subdomains": "1234", "image_ext": "jpeg"}),
-        # "mapquest-aerial": (0, 0, 19, "http://oatile{s}.mqcdn.com/tiles/1.0.0/sat/{z}/{x}/{y}.jpeg", "Tiles Courtesy of Mapquest", {"subdomains": "1234", "image_ext": "jpeg"}),
-        # more to add with
-        # https://github.com/leaflet-extras/leaflet-providers/blob/master/leaflet-providers.js
-        # not working ?
-        # "openseamap": (0, 0, 19, "http://tiles.openseamap.org/seamark/{z}/{x}/{y}.png",
-        #    "Map data @ OpenSeaMap contributors"),
     }
 
     def __init__(
@@ -111,6 +61,7 @@ class MapSource:
         image_ext="png",
         attribution="© OpenStreetMap contributors",
         subdomains="abc",
+        quad_key = False,
         **kwargs
     ):
         if cache_key is None:
@@ -124,6 +75,7 @@ class MapSource:
         self.image_ext = image_ext
         self.attribution = attribution
         self.subdomains = subdomains
+        self.quad_key = quad_key
         self.cache_fmt = "{cache_key}_{zoom}_{tile_x}_{tile_y}.{image_ext}"
         self.dp_tile_size = min(dp(self.tile_size), self.tile_size * 2)
         self.default_lat = self.default_lon = self.default_zoom = None
@@ -132,6 +84,7 @@ class MapSource:
 
     @staticmethod
     def from_provider(key, **kwargs):
+        quad_key = kwargs.get('quad_key', False)
         provider = MapSource.providers[key]
         cache_dir = kwargs.get('cache_dir', CACHE_DIR)
         options = {}
@@ -145,6 +98,7 @@ class MapSource:
             url=url,
             cache_dir=cache_dir,
             attribution=attribution,
+            quad_key=quad_key,
             **options
         )