add get_bbox

geodataset/geodataset.py

@@ -359,21 +359,34 @@ def get_lonlat_arrays(self):
         # if lon and lat are arrays
         return [self.get_variable_array(name) for name in self.lonlat_names]
 
-    def get_area_euclidean(self, pyproj_map):
+    def get_area_euclidean(self, mapping):
         """
         Calculates element area from netcdf file
         Assumes regular grid in the given projection
 
         Parameters:
         -----------
-        pyproj_map : pyproj.Proj
+        mapping : pyproj.Proj
 
         Returns:
         --------
         * area (float)
         """
         lon, lat = self.get_lonlat_arrays()
-        x, y = pyproj_map(lon, lat)
+        x, y = mapping(lon, lat)
         dy = np.max([np.abs(np.mean(y[:, 2]-y[:, 1])), np.abs(np.mean(y[1, :]-y[0, :]))])
         dx = np.max([np.abs(np.mean(x[:, 2]-x[:, 1])), np.abs(np.mean(x[1, :]-x[0, :]))])
         return np.abs(dx*dy)
+
+    def get_bbox(self, mapping):
+        """ Get bounding box (extent)
+        Parameters:
+        * mapping: pyproj mapping
+
+        Returns:
+        * bbox = [xmin, xmax, ymin, ymax], where x,y are coordinates specified by mapping
+        """
+
+        lon, lat = self.get_lonlat_arrays()
+        x, y = mapping(lon, lat)
+        return [x.min(), x.max(), y.min(), y.max()]

geodataset/tests/test_geodataset.py

@@ -334,17 +334,34 @@ def test_projection(self):
             __exit__=MagicMock(return_value=None),
             get_lonlat_arrays=DEFAULT,
             )
-    def test_get_lonlat_names_raises(self, **kwargs):
+    def test_get_area_euclidean(self, **kwargs):
         ''' test f4 with _FillValue defined '''
         p = pyproj.Proj(3411)
-
-        kwargs['get_lonlat_arrays'].return_value = (
+        GeoDatasetRead.get_lonlat_arrays.return_value = (
             np.array([[1,2,3],[1,2,3],[1,2,3]]),
             np.array([[1,1,1],[2,2,2],[3,3,3]]))
 
         with GeoDatasetRead() as ds:
             area = ds.get_area_euclidean(p)
             self.assertAlmostEqual(area, 23354252971.32609)
 
+    @patch.multiple(GeoDatasetRead,
+            __init__=MagicMock(return_value=None),
+            __exit__=MagicMock(return_value=None),
+            get_lonlat_arrays=DEFAULT,
+            )
+    def test_get_bbox(self, **kwargs):
+        ''' test f4 with _FillValue defined '''
+        p = pyproj.Proj(3411)
+        GeoDatasetRead.get_lonlat_arrays.return_value = (
+            np.array([[1,2,3],[1,2,3],[1,2,3]]),
+            np.array([[1,1,1],[2,2,2],[3,3,3]]))
+
+        with GeoDatasetRead() as ds:
+            bbox = ds.get_bbox(p)
+            self.assertAlmostEqual(bbox,
+            [8420199.606917838, 9005961.652806347, 
+            -8418368.037664523, -7832478.150085783])
+
 if __name__ == "__main__":
     unittest.main()