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-rw-r--r--src/iso19111/c_api.cpp24
1 files changed, 18 insertions, 6 deletions
diff --git a/src/iso19111/c_api.cpp b/src/iso19111/c_api.cpp
index f3badb51..5f34a22b 100644
--- a/src/iso19111/c_api.cpp
+++ b/src/iso19111/c_api.cpp
@@ -2158,14 +2158,26 @@ PJ *proj_get_target_crs(PJ_CONTEXT *ctx, const PJ *obj) {
* The method returns a list of matching reference CRS, and the percentage
* (0-100) of confidence in the match. The list is sorted by decreasing
* confidence.
- *
- * 100% means that the name of the reference entry
+ * <ul>
+ * <li>100% means that the name of the reference entry
* perfectly matches the CRS name, and both are equivalent. In which case a
* single result is returned.
- * 90% means that CRS are equivalent, but the names are not exactly the same.
- * 70% means that CRS are equivalent), but the names do not match at all.
- * 25% means that the CRS are not equivalent, but there is some similarity in
- * the names.
+ * Note: in the case of a GeographicCRS whose axis
+ * order is implicit in the input definition (for example ESRI WKT), then axis
+ * order is ignored for the purpose of identification. That is the CRS built
+ * from
+ * GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],
+ * PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]
+ * will be identified to EPSG:4326, but will not pass a
+ * isEquivalentTo(EPSG_4326, util::IComparable::Criterion::EQUIVALENT) test,
+ * but rather isEquivalentTo(EPSG_4326,
+ * util::IComparable::Criterion::EQUIVALENT_EXCEPT_AXIS_ORDER_GEOGCRS)
+ * </li>
+ * <li>90% means that CRS are equivalent, but the names are not exactly the same.</li>
+ * <li>70% means that CRS are equivalent), but the names do not match at all.</li>
+ * <li>25% means that the CRS are not equivalent, but there is some similarity in
+ * the names.</li>
+ * </ul>
* Other confidence values may be returned by some specialized implementations.
*
* This is implemented for GeodeticCRS, ProjectedCRS, VerticalCRS and