ENH: add guess_wkt_version to return the WKT version of a string

docs/api/crs/crs.rst

@@ -83,6 +83,12 @@ CustomConstructorCRS
     :special-members: __init__
 
 
+guess_wkt_version
+-----------------
+
+.. autofunction:: pyproj.crs.guess_wkt_version
+
+
 is_wkt
 -----------------
 

docs/history.rst

@@ -3,6 +3,7 @@ Change Log
 
 Latest
 ------
+- ENH: Added :func:`pyproj.crs.guess_wkt_version` to return the WKT version of a string (issue #1031)
 - WHL: Wheels contain PROJ 9.7.1 (pull #1573)
 - WHL: Upgrade from MacOS 13 to MacOS 15 (X86_64) wheels (issue #1532 & #1543)
 - ENH: Add :meth:`database.query_geodetic_crs_from_datum` (pull #1390)

pyproj/_crs.pyi

@@ -230,4 +230,5 @@ class _CRS(Base):
 
 def is_proj(proj_string: str) -> bool: ...
 def is_wkt(proj_string: str) -> bool: ...
+def guess_wkt_version(proj_string: str) -> Optional[WktVersion]: ...
 def _load_proj_json(in_proj_json: str) -> dict: ...

pyproj/_crs.pyx

@@ -49,6 +49,38 @@ def is_wkt(str proj_string not None):
     return proj_context_guess_wkt_dialect(NULL, b_proj_string) != PJ_GUESSED_NOT_WKT
 
 
+def guess_wkt_version(str proj_string not None):
+    """
+    .. versionadded:: 3.8.0
+
+    Guess the version of the Well-Known Text format of the input string.
+
+    Parameters
+    ----------
+    proj_string: str
+        The projection string.
+
+    Returns
+    -------
+    Optional[pyproj.enums.WktVersion]:
+        The WKT version of the string or None if it is not WKT.
+    """
+    cdef bytes b_proj_string = cstrencode(proj_string)
+    cdef PJ_GUESSED_WKT_DIALECT dialect = proj_context_guess_wkt_dialect(
+        NULL, b_proj_string
+    )
+    # PJ_GUESSED_WKT2_2018 is the legacy alias of PJ_GUESSED_WKT2_2019.
+    if dialect == PJ_GUESSED_WKT2_2019:
+        return WktVersion.WKT2_2019
+    if dialect == PJ_GUESSED_WKT2_2015:
+        return WktVersion.WKT2_2015
+    if dialect == PJ_GUESSED_WKT1_GDAL:
+        return WktVersion.WKT1_GDAL
+    if dialect == PJ_GUESSED_WKT1_ESRI:
+        return WktVersion.WKT1_ESRI
+    return None
+
+
 def is_proj(str proj_string not None):
     """
     .. versionadded:: 2.2.2

pyproj/crs/__init__.py

@@ -10,6 +10,7 @@
     Datum,
     Ellipsoid,
     PrimeMeridian,
+    guess_wkt_version,
     is_proj,
     is_wkt,
 )
@@ -36,6 +37,7 @@
     "GeographicCRS",
     "ProjectedCRS",
     "VerticalCRS",
+    "guess_wkt_version",
     "is_proj",
     "is_wkt",
 ]

pyproj/proj.pxi

@@ -298,6 +298,7 @@ cdef extern from "proj.h" nogil:
     void proj_int_list_destroy(int* list)
     void proj_context_use_proj4_init_rules(PJ_CONTEXT *ctx, int enable)
     ctypedef enum PJ_GUESSED_WKT_DIALECT:
+        PJ_GUESSED_WKT2_2019
         PJ_GUESSED_WKT2_2018
         PJ_GUESSED_WKT2_2015
         PJ_GUESSED_WKT1_GDAL

test/crs/test_crs.py

@@ -15,6 +15,7 @@
     Datum,
     Ellipsoid,
     PrimeMeridian,
+    guess_wkt_version,
 )
 from pyproj.crs.enums import CoordinateOperationType, DatumType
 from pyproj.enums import ProjVersion, WktVersion
@@ -1000,6 +1001,24 @@ def test_to_wkt_enum__invalid():
         crs.to_wkt("WKT_INVALID")
 
 
+@pytest.mark.parametrize(
+    "wkt_version",
+    [
+        WktVersion.WKT2_2019,
+        WktVersion.WKT2_2015,
+        WktVersion.WKT1_GDAL,
+        WktVersion.WKT1_ESRI,
+    ],
+)
+def test_guess_wkt_version(wkt_version):
+    crs = CRS.from_epsg(4326)
+    assert guess_wkt_version(crs.to_wkt(wkt_version)) == wkt_version
+
+
+def test_guess_wkt_version__not_wkt():
+    assert guess_wkt_version("+proj=longlat +datum=WGS84 +no_defs +type=crs") is None
+
+
 @pytest.mark.parametrize(
     "wkt_version",
     ["WKT2_2015", "WKT2_2015_SIMPLIFIED", "WKT1_GDAL", "WKT1_ESRI"],