DerivedGeographicCRS: allow exporting +proj=ob_tran +o_proj=longlat to PROJ string

2 files changed, 16 insertions, 1 deletions

diff --git a/src/iso19111/crs.cpp b/src/iso19111/crs.cpp
index e4e05166..d0e23f95 100644
--- a/src/iso19111/crs.cpp
+++ b/src/iso19111/crs.cpp
@@ -4736,8 +4736,18 @@ void DerivedGeographicCRS::_exportToWKT(io::WKTFormatter *formatter) const {
 // ---------------------------------------------------------------------------
 
 void DerivedGeographicCRS::_exportToPROJString(
-    io::PROJStringFormatter *) const // throw(io::FormattingException)
+    io::PROJStringFormatter *formatter) const // throw(io::FormattingException)
 {
+    const auto &l_conv = derivingConversionRef();
+    const auto &methodName = l_conv->method()->nameStr();
+    if (methodName == "PROJ ob_tran o_proj=longlat" ||
+        methodName == "PROJ ob_tran o_proj=lonlat" ||
+        methodName == "PROJ ob_tran o_proj=latlong" ||
+        methodName == "PROJ ob_tran o_proj=latlon") {
+        l_conv->_exportToPROJString(formatter);
+        return;
+    }
+
     throw io::FormattingException(
         "DerivedGeographicCRS cannot be exported to PROJ string");
 }
diff --git a/test/unit/test_crs.cpp b/test/unit/test_crs.cpp
index 605df714..aee4dd73 100644
--- a/test/unit/test_crs.cpp
+++ b/test/unit/test_crs.cpp
@@ -4093,6 +4093,11 @@ TEST(crs, derivedGeographicCRS_to_PROJ) {
     auto obj = WKTParser().createFromWKT(wkt);
     auto crs = nn_dynamic_pointer_cast<DerivedGeographicCRS>(obj);
     ASSERT_TRUE(crs != nullptr);
+    EXPECT_EQ(
+        crs->exportToPROJString(PROJStringFormatter::create().get()),
+        "+proj=ob_tran +o_proj=longlat +o_lat_p=52 +o_lon_p=-30 +lon_0=-25 "
+        "+datum=WGS84 +no_defs +type=crs");
+
     auto op = CoordinateOperationFactory::create()->createOperation(
         crs->baseCRS(), NN_NO_CHECK(crs));
     ASSERT_TRUE(op != nullptr);