ENH: add is_empty

src/accessors-geog.cpp

@@ -26,6 +26,10 @@ PyObjectGeography convex_hull(PyObjectGeography a) {
     return make_py_geography(s2geog::s2_convex_hull(a_ptr));
 }
 
+bool is_empty(PyObjectGeography a) {
+    return s2geog::s2_is_empty(a.as_geog_ptr()->geog());
+}
+
 double distance(PyObjectGeography a, PyObjectGeography b, double radius = EARTH_RADIUS_METERS) {
     const auto& a_index = a.as_geog_ptr()->geog_index();
     const auto& b_index = b.as_geog_ptr()->geog_index();
@@ -78,6 +82,19 @@ void init_accessors(py::module& m) {
 
     )pbdoc");
 
+    m.def("is_empty",
+          py::vectorize(&is_empty),
+          py::arg("a"),
+          R"pbdoc(
+        Returns True if the geography object is empty, False otherwise.
+
+        Parameters
+        ----------
+        a : :py:class:`Geography` or array_like
+            Geography object
+
+    )pbdoc");
+
     m.def("distance",
           py::vectorize(&distance),
           py::arg("a"),

src/spherely.pyi

@@ -182,6 +182,7 @@ is_geography: _VFunc_Nin1_Nout1[Literal["is_geography"], bool, bool]
 is_prepared: _VFunc_Nin1_Nout1[Literal["is_prepared"], bool, bool]
 prepare: _VFunc_Nin1_Nout1[Literal["prepare"], Geography, Any]
 destroy_prepared: _VFunc_Nin1_Nout1[Literal["destroy_prepared"], Geography, Any]
+is_empty: _VFunc_Nin1_Nout1[Literal["is_empty"], bool, bool]
 
 # predicates
 

tests/test_accessors.py

@@ -84,6 +84,24 @@ def test_convex_hull(geog, expected) -> None:
     assert spherely.equals(actual, expected)
 
 
+def test_is_empty():
+    arr = spherely.from_wkt(
+        [
+            "POINT (0 0)",
+            "POINT EMPTY",
+            "LINESTRING (0 0, 1 1)",
+            "LINESTRING EMPTY",
+            "POLYGON ((0 0, 10 0, 10 10, 0 10, 0 0))",
+            "POLYGON EMPTY",
+            "GEOMETRYCOLLECTION EMPTY",
+            "GEOMETRYCOLLECTION (POINT EMPTY)",
+        ]
+    )
+    result = spherely.is_empty(arr)
+    expected = np.array([False, True, False, True, False, True, True, True])
+    np.testing.assert_array_equal(result, expected)
+
+
 @pytest.mark.parametrize(
     "geog_a, geog_b, expected",
     [