From a6897da6d91ce61510813a9d694b83a46679bc22 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Sun, 25 Sep 2022 12:59:08 +0200
Subject: [PATCH] Merge pull request #3342 from rouault/fix_3340

WKT import: 3D-promote base CRS of 3D DerivedProjectedCRS (fixes #3340)
---
 src/iso19111/io.cpp    |  7 +++++++
 test/unit/test_crs.cpp | 15 +++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/src/iso19111/io.cpp b/src/iso19111/io.cpp
index 09437d3dcf..241accf0fb 100644
--- a/src/iso19111/io.cpp
+++ b/src/iso19111/io.cpp
@@ -5145,6 +5145,13 @@ WKTParser::Private::buildDerivedProjectedCRS(const WKTNodeNNPtr &node) {
         ThrowMissing(WKTConstants::CS_);
     }
     auto cs = buildCS(csNode, node, UnitOfMeasure::NONE);
+
+    if (cs->axisList().size() == 3 &&
+        baseProjCRS->coordinateSystem()->axisList().size() == 2) {
+        baseProjCRS = NN_NO_CHECK(util::nn_dynamic_pointer_cast<ProjectedCRS>(
+            baseProjCRS->promoteTo3D(std::string(), dbContext_)));
+    }
+
     return DerivedProjectedCRS::create(buildProperties(node), baseProjCRS,
                                        conversion, cs);
 }
diff --git a/test/unit/test_crs.cpp b/test/unit/test_crs.cpp
index 7928270858..e16ea308ad 100644
--- a/test/unit/test_crs.cpp
+++ b/test/unit/test_crs.cpp
@@ -6821,6 +6821,21 @@ TEST(crs, promoteTo3D_and_demoteTo2D) {
         EXPECT_TRUE(crs3DAsDerivedProj->promoteTo3D(std::string(), nullptr)
                         ->isEquivalentTo(crs3DAsDerivedProj.get()));
 
+        // Check that importing an exported DerivedProjected 3D CRS as WKT keeps
+        // the 3D aspect of the baseCRS (see #3340)
+        {
+            WKTFormatterNNPtr f(
+                WKTFormatter::create(WKTFormatter::Convention::WKT2_2019));
+            crs3DAsDerivedProj->exportToWKT(f.get());
+            auto obj = WKTParser().createFromWKT(f->toString());
+            auto crsFromWkt = nn_dynamic_pointer_cast<DerivedProjectedCRS>(obj);
+            ASSERT_TRUE(crsFromWkt != nullptr);
+            EXPECT_EQ(crsFromWkt->coordinateSystem()->axisList().size(), 3U);
+            EXPECT_EQ(
+                crsFromWkt->baseCRS()->coordinateSystem()->axisList().size(),
+                3U);
+        }
+
         auto demoted = crs3DAsDerivedProj->demoteTo2D(std::string(), dbContext);
         EXPECT_EQ(demoted->baseCRS()->coordinateSystem()->axisList().size(),
                   2U);