Add is_deprecated and get_non_deprecated() to CRS (#1383)

docs/history.rst

@@ -4,6 +4,7 @@ Change Log
 Latest
 ------
 - DEP: Minimum supported Python version 3.10 (pull #1357)
+- ENH: Add :meth:`CRS.is_deprecated` and :meth:`CRS.get_non_deprecated` (pull #1383)
 
 3.6.1
 ------

pyproj/_crs.pyi

@@ -235,6 +235,9 @@ class _CRS(Base):
     @property
     def is_geocentric(self) -> bool: ...
     def equals(self, other: Any, ignore_axis_order: bool) -> bool: ...
+    @property
+    def is_deprecated(self) -> bool: ...
+    def get_non_deprecated(self) -> list["_CRS"]: ...
 
 def is_proj(proj_string: str) -> bool: ...
 def is_wkt(proj_string: str) -> bool: ...

pyproj/_crs.pyx

@@ -3203,3 +3203,60 @@ cdef class _CRS(Base):
         if not isinstance(other, _CRS):
             return False
         return self._equals(other, ignore_axis_order=ignore_axis_order)
+
+    @property
+    def is_deprecated(self):
+        """
+        .. versionadded:: 3.7.0
+
+        Check if the CRS is deprecated
+
+        Returns
+        -------
+        bool
+        """
+        return bool(proj_is_deprecated(self.projobj))
+
+    def get_non_deprecated(self):
+        """
+        .. versionadded:: 3.7.0
+
+        Return a list of non-deprecated objects related to this.
+
+        Returns
+        -------
+        list[_CRS]
+        """
+
+        non_deprecated = []
+
+        cdef PJ_OBJ_LIST *proj_list = NULL
+        cdef int num_proj_objects = 0
+
+        proj_list = proj_get_non_deprecated(
+            self.context,
+            self.projobj
+        )
+        if proj_list != NULL:
+            num_proj_objects = proj_list_get_count(proj_list)
+
+        cdef PJ* proj = NULL
+        try:
+            for iii in range(num_proj_objects):
+                proj = proj_list_get(self.context, proj_list, iii)
+                non_deprecated.append(_CRS(_to_wkt(
+                    self.context,
+                    proj,
+                    version=WktVersion.WKT2_2019,
+                    pretty=False,
+                )))
+                proj_destroy(proj)
+                proj = NULL
+        finally:
+            # If there was an error we have to call proj_destroy
+            # If there was none, calling it on NULL does nothing
+            proj_destroy(proj)
+            proj_list_destroy(proj_list)
+            _clear_proj_error()
+
+        return non_deprecated

pyproj/crs/crs.py

@@ -1565,6 +1565,31 @@ def is_derived(self):
         """
         return self._crs.is_derived
 
+    @property
+    def is_deprecated(self) -> bool:
+        """
+        .. versionadded:: 3.7.0
+
+        Check if the CRS is deprecated
+
+        Returns
+        -------
+        bool
+        """
+        return self._crs.is_deprecated
+
+    def get_non_deprecated(self) -> list["CRS"]:
+        """
+        .. versionadded:: 3.7.0
+
+        Return a list of non-deprecated objects related to this.
+
+        Returns
+        -------
+        list[CRS]
+        """
+        return self._crs.get_non_deprecated()
+
     def __eq__(self, other: Any) -> bool:
         return self.equals(other)
 

pyproj/proj.pxi

@@ -546,3 +546,6 @@ cdef extern from "proj.h" nogil:
     )
     void proj_unit_list_destroy(PROJ_UNIT_INFO** list)
     const char *proj_context_get_url_endpoint(PJ_CONTEXT* ctx)
+
+    int proj_is_deprecated(const PJ *obj)
+    PJ_OBJ_LIST *proj_get_non_deprecated(PJ_CONTEXT *ctx, const PJ *obj)

test/crs/test_crs.py

@@ -232,6 +232,36 @@ def test_to_wkt_pretty():
     assert "\n" not in crs.to_wkt()
 
 
+def test_no_non_deprecated():
+    crs = CRS.from_epsg(4326)
+    assert not crs.is_deprecated
+    non_dep = crs.get_non_deprecated()
+    assert len(non_dep) == 0
+
+
+def test_non_deprecated():
+    crs = CRS.from_epsg(28473)
+    assert crs.is_deprecated
+    non_dep = crs.get_non_deprecated()
+    assert len(non_dep) == 1
+    assert "EPSG:2503" == ":".join(non_dep[0].to_authority())
+
+
+def test_non_deprecated_empty():
+    crs = CRS.from_epsg(3151)
+    assert crs.is_deprecated
+    assert len(crs.get_non_deprecated()) == 0
+
+
+def test_non_deprecated_multiple():
+    crs = CRS.from_epsg(3315)
+    assert crs.is_deprecated
+    non_dep = [":".join(el.to_authority()) for el in crs.get_non_deprecated()]
+    assert len(non_dep) == 4
+    for elem in ["EPSG:3989", "EPSG:3988", "EPSG:3987", "EPSG:3986"]:
+        assert elem in non_dep
+
+
 @pytest.mark.parametrize(
     "version, expected",
     [