Assorted set of fixes for PROJString to ISO19111 model:

- createFromPROJString(): take into account axisswap step for Krovak and Transverse Mercator (South Orientated)
- Geocentric export to PROJ4: use datum when possible, and add explicit units=m
- ESRI WKT parser: make it case insensitive to parameter and projection names, and more tolerant about possible parameter name aliases
- import from WKT1 for Polar_Stereographic: don't be case sensitive
- importFromPROJString: allow pm to override datum
- Equidistant cylindrical: add support for non-standard latitude of natural origin, used in a GDAL test case
- tmerc export to PROJString: use 'k' instead of 'k_0'
- pj_ellps: use official value from EPSG for reverse flattening of Airy ellipsoid
- GDAL compatibility: add support for importing odd formulations of Mercator as WKT1, but rejecting them when exporting to PROJ
- Add export of 'Geostationary Satellite (Sweep X)' to WKT1_GDAL via EXTENSION.PROJ4 node
- importFromPROJString: add support for +f
- WKT1 / PROJ4: add support for EXTENSION.PROJ4 nodes and +wktext
- exportToWKT: change way we deal with AXIS by default for WKT1_GDAL
- Improve etmerc handling
- Fix WKT import of peg_point_heading for Spherical_Cross_Track_Height
- International Map of the World Polyconic: change parameter mapping
- exportToPROJ: add alpha parameter
- Hotine_Oblique_Mercator_Two_Point_Natural_Origin: GDAL_WKT1 related fix
- GDAL compatibility improvements in import from PROJ4 / WKT1 for polar stereographic
- Add support for +towgs84 when importing a +proj=geocent
- import from WKT1: add support for an odd Mercator_1SP formulation handled by GDAL
- export to proj4 strings: add +units=m to projected CRS for better GDAL compatibility
- export to proj4 strings: add +no_defs to CRS for better GDAL compatibility

1 files changed, 14 insertions, 3 deletions

diff --git a/src/c_api.cpp b/src/c_api.cpp
index 1720a7a1..fbba0f51 100644
--- a/src/c_api.cpp
+++ b/src/c_api.cpp
@@ -839,7 +839,10 @@ static const char *getOptionValue(const char *option,
  * <li>MULTILINE=YES/NO. Defaults to YES, except for WKT1_ESRI</li>
  * <li>INDENTATION_WIDTH=number. Defauls to 4 (when multiline output is
  * on).</li>
- * <li>OUTPUT_AXIS=YES/NO. Defaults to YES, except for WKT1_ESRI.</li>
+ * <li>OUTPUT_AXIS=AUTO/YES/NO. In AUTO mode, axis will be output for WKT2
+ * variants, for WKT1_GDAL for ProjectedCRS with easting/northing ordering
+ * (otherwise stripped), but not for WKT1_ESRI. Setting to YES will output
+ * them unconditionaly, and to NO will omit them unconditionaly.</li>
  * </ul>
  * @return a string, or NULL in case of error.
  */
@@ -890,7 +893,12 @@ const char *proj_obj_as_wkt(PJ_OBJ *obj, PJ_WKT_TYPE type,
             } else if ((value = getOptionValue(*iter, "INDENTATION_WIDTH="))) {
                 formatter->setIndentationWidth(std::atoi(value));
             } else if ((value = getOptionValue(*iter, "OUTPUT_AXIS="))) {
-                formatter->setOutputAxis(ci_equal(value, "YES"));
+                if (!ci_equal(value, "AUTO")) {
+                    formatter->setOutputAxis(
+                        ci_equal(value, "YES")
+                            ? WKTFormatter::OutputAxisRule::YES
+                            : WKTFormatter::OutputAxisRule::NO);
+                }
             } else {
                 std::string msg("Unknown option :");
                 msg += *iter;
@@ -925,7 +933,8 @@ const char *proj_obj_as_wkt(PJ_OBJ *obj, PJ_WKT_TYPE type,
  * @param options NULL-terminated list of strings with "KEY=VALUE" format. or
  * NULL.
  * The currently recognized option is USE_ETMERC=YES to use
- * +proj=etmerc instead of +proj=tmerc
+ * +proj=etmerc instead of +proj=tmerc (or USE_ETMERC=NO to disable implicit
+ * use of etmerc by utm conversions)
  * @return a string, or NULL in case of error.
  */
 const char *proj_obj_as_proj_string(PJ_OBJ *obj, PJ_PROJ_STRING_TYPE type,
@@ -960,6 +969,8 @@ const char *proj_obj_as_proj_string(PJ_OBJ *obj, PJ_PROJ_STRING_TYPE type,
         if (options != nullptr && options[0] != nullptr) {
             if (ci_equal(options[0], "USE_ETMERC=YES")) {
                 formatter->setUseETMercForTMerc(true);
+            } else if (ci_equal(options[0], "USE_ETMERC=NO")) {
+                formatter->setUseETMercForTMerc(false);
             }
         }
         obj->lastPROJString = exportable->exportToPROJString(formatter.get());