[core] Fix get_bounds behavior in core (#2012)

* [core] Fix get_bounds behavior in core.

Also:
- added alias for getBounds,
- fixed an issue where geemap crashed without a helpful message if the map hadn't been added to the screen, and
- added some unit tests.

The behavior was correct in geemap non-core.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Rename as_geo_json to as_geojson

* Rename as_geo_json to as_geojson

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Qiusheng Wu <giswqs@gmail.com>

geemap/core.py

@@ -502,9 +502,29 @@ def set_zoom(self, value: int) -> None:
     def get_center(self) -> Sequence:
         return self.center
 
-    def get_bounds(self) -> Sequence:
+    def get_bounds(self, as_geojson: bool = False) -> Sequence:
+        """Returns the bounds of the current map view.
+
+        Args:
+            as_geojson (bool, optional): If true, returns map bounds as
+                GeoJSON. Defaults to False.
+
+        Returns:
+            list|dict: A list in the format [west, south, east, north] in
+                degrees or a GeoJSON dictionary.
+        """
         bounds = self.bounds
-        return [bounds[0][0], bounds[0][1], bounds[1][0], bounds[1][1]]
+        if not bounds:
+            raise RuntimeError(
+                "Map bounds are undefined. Please display the " "map then try again."
+            )
+        # ipyleaflet returns bounds in the format [[south, west], [north, east]]
+        # https://ipyleaflet.readthedocs.io/en/latest/map_and_basemaps/map.html#ipyleaflet.Map.fit_bounds
+        coords = [bounds[0][1], bounds[0][0], bounds[1][1], bounds[1][0]]
+
+        if as_geojson:
+            return ee.Geometry.BBox(*coords).getInfo()
+        return coords
 
     def get_scale(self) -> float:
         # Reference:
@@ -901,3 +921,4 @@ def _on_layers_change(self, change) -> None:
     addLayer = add_layer
     centerObject = center_object
     setCenter = set_center
+    getBounds = get_bounds

geemap/geemap.py

@@ -1137,17 +1137,7 @@ def get_bounds(self, asGeoJSON=False):
         Returns:
             list | dict: A list in the format [west, south, east, north] in degrees.
         """
-        bounds = self.bounds
-        coords = [bounds[0][1], bounds[0][0], bounds[1][1], bounds[1][0]]
-
-        if asGeoJSON:
-            return ee.Geometry.BBox(
-                bounds[0][1], bounds[0][0], bounds[1][1], bounds[1][0]
-            ).getInfo()
-        else:
-            return coords
-
-    getBounds = get_bounds
+        return super().get_bounds(as_geo_json=asGeoJSON)
 
     def add_cog_layer(
         self,

tests/fake_ee.py

@@ -96,6 +96,12 @@ def getInfo(self, *_, **__):
                 "type": "Point",
                 "coordinates": [120, -70],
             }
+        if self.type().value == "BBox":
+            return {
+                "geodesic": False,
+                "type": "Polygon",
+                "coordinates": [[0, 1], [1, 2], [0, 1]],
+            }
         raise ValueError("Unexpected geometry type in test: ", self.type().value)
 
     def __eq__(self, other: object):

tests/test_core.py

@@ -89,6 +89,23 @@ def test_center_object(self):
         with self.assertRaisesRegex(ValueError, "Zoom must be an integer"):
             self.core_map.center_object(ee.Geometry.Point(), "2")
 
+    @unittest.mock.patch.object(core.Map, "bounds")
+    def test_get_bounds(self, mock_bounds):
+        """Tests that `get_bounds` returns the bounds of the map."""
+        mock_bounds.__get__ = Mock(return_value=[[1, 2], [3, 4]])
+        self.assertEqual(self.core_map.get_bounds(), [2, 1, 4, 3])
+        self.assertEqual(self.core_map.getBounds(), [2, 1, 4, 3])
+        expected_geo_json = {
+            "geodesic": False,
+            "type": "Polygon",
+            "coordinates": [[0, 1], [1, 2], [0, 1]],
+        }
+        self.assertEqual(self.core_map.get_bounds(as_geojson=True), expected_geo_json)
+
+        mock_bounds.__get__ = Mock(return_value=())
+        with self.assertRaisesRegex(RuntimeError, "Map bounds are undefined"):
+            self.core_map.get_bounds(as_geojson=True)
+
     def test_add_basic_widget_by_name(self):
         """Tests that `add` adds widgets by name."""
         self._clear_default_widgets()