Merge pull request #2111 from PROJ-BOT/backport-2109-to-7.0

[Backport 7.0] Fix working of Helmert transform between the horizontal part of 2 compoundCRS (fixes #2108)

1 files changed, 20 insertions, 0 deletions

diff --git a/src/iso19111/coordinateoperation.cpp b/src/iso19111/coordinateoperation.cpp
index 83c0516e..dd794fe4 100644
--- a/src/iso19111/coordinateoperation.cpp
+++ b/src/iso19111/coordinateoperation.cpp
@@ -8929,6 +8929,16 @@ static void setupPROJGeodeticSourceCRS(io::PROJStringFormatter *formatter,
                                        const crs::CRSNNPtr &crs, bool addPushV3,
                                        const char *trfrm_name) {
     auto sourceCRSGeog = dynamic_cast<const crs::GeographicCRS *>(crs.get());
+    if (!sourceCRSGeog) {
+        auto compoundCRS = dynamic_cast<const crs::CompoundCRS *>(crs.get());
+        if (compoundCRS) {
+            const auto &components = compoundCRS->componentReferenceSystems();
+            if (!components.empty()) {
+                sourceCRSGeog = dynamic_cast<const crs::GeographicCRS *>(
+                    components[0].get());
+            }
+        }
+    }
     if (sourceCRSGeog) {
         formatter->startInversion();
         sourceCRSGeog->_exportToPROJString(formatter);
@@ -8957,6 +8967,16 @@ static void setupPROJGeodeticTargetCRS(io::PROJStringFormatter *formatter,
                                        const crs::CRSNNPtr &crs, bool addPopV3,
                                        const char *trfrm_name) {
     auto targetCRSGeog = dynamic_cast<const crs::GeographicCRS *>(crs.get());
+    if (!targetCRSGeog) {
+        auto compoundCRS = dynamic_cast<const crs::CompoundCRS *>(crs.get());
+        if (compoundCRS) {
+            const auto &components = compoundCRS->componentReferenceSystems();
+            if (!components.empty()) {
+                targetCRSGeog = dynamic_cast<const crs::GeographicCRS *>(
+                    components[0].get());
+            }
+        }
+    }
     if (targetCRSGeog) {
         formatter->addStep("cart");
         formatter->setCurrentStepInverted(true);