From 89130c37646b5a785cc364ee3cd8f0ce63c82f26 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Thu, 4 Aug 2022 16:20:07 +0200
Subject: [PATCH] WKT parser: fix issue when parsing some WKT1 with
 Hotine_Oblique_Mercator_Azimuth_Center and ignoring rectified_grid_angle
 (fixes #3279)

---
 src/iso19111/io.cpp   | 15 +++++++++++----
 test/unit/test_io.cpp | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/src/iso19111/io.cpp b/src/iso19111/io.cpp
index 6c5bc85b17..d58854e999 100644
--- a/src/iso19111/io.cpp
+++ b/src/iso19111/io.cpp
@@ -7604,10 +7604,17 @@ WKTParser::guessDialect(const std::string &wkt) noexcept {
     for (const auto &pointerKeyword : wkt1_keywords) {
         if (ci_starts_with(wkt, *pointerKeyword)) {
 
-            if (ci_find(wkt, "GEOGCS[\"GCS_") != std::string::npos ||
-                (!ci_starts_with(wkt, WKTConstants::LOCAL_CS) &&
-                 ci_find(wkt, "AXIS[") == std::string::npos &&
-                 ci_find(wkt, "AUTHORITY[") == std::string::npos)) {
+            if ((ci_find(wkt, "GEOGCS[\"GCS_") != std::string::npos ||
+                 (!ci_starts_with(wkt, WKTConstants::LOCAL_CS) &&
+                  ci_find(wkt, "AXIS[") == std::string::npos &&
+                  ci_find(wkt, "AUTHORITY[") == std::string::npos)) &&
+                // WKT1:GDAL and WKT1:ESRI have both a
+                // Hotine_Oblique_Mercator_Azimuth_Center If providing a
+                // WKT1:GDAL without AXIS, we may wrongly detect it as WKT1:ESRI
+                // and skip the rectified_grid_angle parameter cf
+                // /~https://github.com/OSGeo/PROJ/issues/3279
+                ci_find(wkt, "PARAMETER[\"rectified_grid_angle") ==
+                    std::string::npos) {
                 return WKTGuessedDialect::WKT1_ESRI;
             }
 
diff --git a/test/unit/test_io.cpp b/test/unit/test_io.cpp
index 6135991661..6af58507d2 100644
--- a/test/unit/test_io.cpp
+++ b/test/unit/test_io.cpp
@@ -1926,6 +1926,38 @@ TEST(wkt_parse, wkt1_hotine_oblique_mercator_with_rectified_grid_angle) {
 
 // ---------------------------------------------------------------------------
 
+TEST(wkt_parse,
+     wkt1_hotine_oblique_mercator_azimuth_center_with_rectified_grid_angle) {
+    auto wkt = "PROJCS[\"unknown\","
+               "GEOGCS[\"unknown\","
+               "    DATUM[\"WGS_1984\","
+               "        SPHEROID[\"WGS 84\",6378137,298.257223563]],"
+               "    PRIMEM[\"Greenwich\",0],"
+               "    UNIT[\"degree\",0.0174532925199433]],"
+               "PROJECTION[\"Hotine_Oblique_Mercator_Azimuth_Center\"],"
+               "PARAMETER[\"latitude_of_center\",0],"
+               "PARAMETER[\"longitude_of_center\",0],"
+               "PARAMETER[\"azimuth\",30],"
+               "PARAMETER[\"rectified_grid_angle\",0],"
+               "PARAMETER[\"scale_factor\",1],"
+               "PARAMETER[\"false_easting\",0],"
+               "PARAMETER[\"false_northing\",0],"
+               "UNIT[\"metre\",1]]";
+
+    auto obj = WKTParser().createFromWKT(wkt);
+    auto crs = nn_dynamic_pointer_cast<ProjectedCRS>(obj);
+    ASSERT_TRUE(crs != nullptr);
+
+    // Check that we have not overriden rectified_grid_angle
+    auto got_wkt = crs->exportToWKT(
+        WKTFormatter::create(WKTFormatter::Convention::WKT1_GDAL).get());
+    EXPECT_TRUE(got_wkt.find("PARAMETER[\"rectified_grid_angle\",0]") !=
+                std::string::npos)
+        << got_wkt;
+}
+
+// ---------------------------------------------------------------------------
+
 TEST(proj_export, wkt2_hotine_oblique_mercator_without_rectified_grid_angle) {
     auto wkt = "PROJCRS[\"NAD_1983_Michigan_GeoRef_Meters\",\n"
                "    BASEGEOGCRS[\"NAD83(1986)\",\n"