BUG: fix write of kml lon/lat transpose (#421)

CHANGES.md

@@ -57,6 +57,8 @@
  `write` and `write_dataframe` (#384).
 - Fixed bug preventing reading from bytes or file-like in `read_arrow` /
  `open_arrow` (#407).
+- Fixed bug transposing longitude and latitude when writing files with
+ coordinate transformation from EPSG:4326 (#421).
 
 ### Packaging
 

pyogrio/_io.pyx

@@ -2134,6 +2134,10 @@ cdef create_ogr_dataset_layer(
  if crs is not None:
  try:
  ogr_crs = create_crs(crs)
+ # force geographic CRS to use lon, lat order and ignore axis order specified by CRS, in order
+ # to correctly write KML and GeoJSON coordinates in correct order
+ OSRSetAxisMappingStrategy(ogr_crs, OAMS_TRADITIONAL_GIS_ORDER)
+
 
  except Exception as exc:
  if dataset_options != NULL:
@@ -2735,4 +2739,4 @@ cdef create_fields_from_arrow_schema(
  f"Error while creating field from Arrow for field {i} with name "
  f"'{get_string(child.name)}' and type {get_string(child.format)}"
  f"{gdal_msg}."
- )
+ )

pyogrio/_ogr.pxd

@@ -196,7 +196,10 @@ cdef extern from "ogr_srs_api.h":
  const char* OSRGetAuthorityName(OGRSpatialReferenceH srs, const char *key)
  const char* OSRGetAuthorityCode(OGRSpatialReferenceH srs, const char *key)
  OGRErr OSRImportFromEPSG(OGRSpatialReferenceH srs, int code)
-
+ ctypedef enum OSRAxisMappingStrategy:
+ OAMS_TRADITIONAL_GIS_ORDER
+
+ void OSRSetAxisMappingStrategy(OGRSpatialReferenceH hSRS, OSRAxisMappingStrategy)
  int OSRSetFromUserInput(OGRSpatialReferenceH srs, const char *pszDef)
  void OSRSetPROJSearchPaths(const char *const *paths)
  OGRSpatialReferenceH OSRNewSpatialReference(const char *wkt)

pyogrio/tests/test_geopandas_io.py

@@ -6,7 +6,7 @@
 import numpy as np
 import pytest
 
-from pyogrio import list_layers, read_info, __gdal_version__
+from pyogrio import list_layers, list_drivers, read_info, __gdal_version__
 from pyogrio.errors import DataLayerError, DataSourceError, FeatureError, GeometryError
 from pyogrio.geopandas import read_dataframe, write_dataframe, PANDAS_GE_20
 from pyogrio.raw import (
@@ -2067,3 +2067,77 @@ def test_non_utf8_encoding_shapefile_sql(tmp_path, use_arrow):
  )
  assert actual.columns[0] == mandarin
  assert actual[mandarin].values[0] == mandarin
+
+
+@pytest.mark.requires_arrow_write_api
+def test_write_kml_file_coordinate_order(tmp_path, use_arrow):
+ # confirm KML coordinates are written in lon, lat order even if CRS axis specifies otherwise
+ points = [Point(10, 20), Point(30, 40), Point(50, 60)]
+ gdf = gp.GeoDataFrame(geometry=points, crs="EPSG:4326")
+ output_path = tmp_path / "test.kml"
+ write_dataframe(
+ gdf, output_path, layer="tmp_layer", driver="KML", use_arrow=use_arrow
+ )
+
+ gdf_in = read_dataframe(output_path, use_arrow=use_arrow)
+
+ assert np.array_equal(gdf_in.geometry.values, points)
+
+ if "LIBKML" in list_drivers():
+ # test appending to the existing file only if LIBKML is available
+ # as it appears to fall back on LIBKML driver when appending.
+ points_append = [Point(70, 80), Point(90, 100), Point(110, 120)]
+ gdf_append = gp.GeoDataFrame(geometry=points_append, crs="EPSG:4326")
+
+ write_dataframe(
+ gdf_append,
+ output_path,
+ layer="tmp_layer",
+ driver="KML",
+ use_arrow=use_arrow,
+ append=True,
+ )
+ # force_2d used to only compare xy geometry as z-dimension is undesirably
+ # introduced when the kml file is over-written.
+ gdf_in_appended = read_dataframe(
+ output_path, use_arrow=use_arrow, force_2d=True
+ )
+
+ assert np.array_equal(gdf_in_appended.geometry.values, points + points_append)
+
+
+@pytest.mark.requires_arrow_write_api
+def test_write_geojson_rfc7946_coordinates(tmp_path, use_arrow):
+ points = [Point(10, 20), Point(30, 40), Point(50, 60)]
+ gdf = gp.GeoDataFrame(geometry=points, crs="EPSG:4326")
+ output_path = tmp_path / "test.geojson"
+ write_dataframe(
+ gdf,
+ output_path,
+ layer="tmp_layer",
+ driver="GeoJSON",
+ RFC7946=True,
+ use_arrow=use_arrow,
+ )
+
+ gdf_in = read_dataframe(output_path, use_arrow=use_arrow)
+
+ assert np.array_equal(gdf_in.geometry.values, points)
+
+ # test appending to the existing file
+
+ points_append = [Point(70, 80), Point(90, 100), Point(110, 120)]
+ gdf_append = gp.GeoDataFrame(geometry=points_append, crs="EPSG:4326")
+
+ write_dataframe(
+ gdf_append,
+ output_path,
+ layer="tmp_layer",
+ driver="GeoJSON",
+ RFC7946=True,
+ use_arrow=use_arrow,
+ append=True,
+ )
+
+ gdf_in_appended = read_dataframe(output_path, use_arrow=use_arrow)
+ assert np.array_equal(gdf_in_appended.geometry.values, points + points_append)