From b9f0c642f1a547555c27b069d6cfe488b20a5c6e Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Fri, 7 Jun 2024 18:32:16 +0200
Subject: [PATCH] Internal libgeotiff: resync with
 https://github.com/OSGeo/libgeotiff/pull/118

---
 frmts/gtiff/gt_wkt_srs.cpp             | 17 ++++++++++++-
 frmts/gtiff/libgeotiff/geo_normalize.c | 33 ++++++++++++++++++++++----
 frmts/gtiff/libgeotiff/geo_normalize.h | 12 +++++++---
 frmts/gtiff/libgeotiff/geotiff.h       |  2 +-
 4 files changed, 55 insertions(+), 9 deletions(-)

diff --git a/frmts/gtiff/gt_wkt_srs.cpp b/frmts/gtiff/gt_wkt_srs.cpp
index a1ea06dfac60..919829f2d511 100644
--- a/frmts/gtiff/gt_wkt_srs.cpp
+++ b/frmts/gtiff/gt_wkt_srs.cpp
@@ -1397,7 +1397,8 @@ OGRSpatialReferenceH GTIFGetOGISDefnAsOSR(GTIF *hGTIF, GTIFDefn *psDefn)
         for (; i < 10; i++)
             adfParam[i] = 0.0;
 
-        // libgeotiff is unfortunately inconsistent. When it synthetizes the
+#if LIBGEOTIFF_VERSION <= 1730
+        // libgeotiff <= 1.7.3 is unfortunately inconsistent. When it synthetizes the
         // projection parameters from the EPSG ProjectedCRS code, it returns
         // them normalized in degrees. But when it gets them from
         // ProjCoordTransGeoKey and other Proj....GeoKey's it return them in
@@ -1418,6 +1419,20 @@ OGRSpatialReferenceH GTIFGetOGISDefnAsOSR(GTIF *hGTIF, GTIFDefn *psDefn)
             adfParam[2] *= psDefn->UOMAngleInDegrees;
             adfParam[3] *= psDefn->UOMAngleInDegrees;
         }
+#else
+        // If GTIFF_READ_ANGULAR_PARAMS_IN_DEGREE=YES (non-nominal case), undo
+        // the conversion to degrees, that has been done by libgeotiff > 1.7.3
+        if (GDALGTIFKeyGetSHORT(hGTIF, ProjCoordTransGeoKey, &tmp, 0, 1) &&
+            psDefn->UOMAngleInDegrees != 0 && psDefn->UOMAngleInDegrees != 1 &&
+            CPLTestBool(CPLGetConfigOption(
+                "GTIFF_READ_ANGULAR_PARAMS_IN_DEGREE", "NO")))
+        {
+            adfParam[0] /= psDefn->UOMAngleInDegrees;
+            adfParam[1] /= psDefn->UOMAngleInDegrees;
+            adfParam[2] /= psDefn->UOMAngleInDegrees;
+            adfParam[3] /= psDefn->UOMAngleInDegrees;
+        }
+#endif
 
         /* --------------------------------------------------------------------
          */
diff --git a/frmts/gtiff/libgeotiff/geo_normalize.c b/frmts/gtiff/libgeotiff/geo_normalize.c
index 11517462c761..f16b67be4d9d 100644
--- a/frmts/gtiff/libgeotiff/geo_normalize.c
+++ b/frmts/gtiff/libgeotiff/geo_normalize.c
@@ -2241,15 +2241,16 @@ static void GTIFFetchProjParms( GTIF * psGTIF, GTIFDefn * psDefn )
         break;
     }
 
+    for( int iParam = 0; iParam < psDefn->nParms; iParam++ )
+    {
+        switch( psDefn->ProjParmId[iParam] )
+        {
+
 /* -------------------------------------------------------------------- */
 /*      Normalize any linear parameters into meters.  In GeoTIFF        */
 /*      the linear projection parameter tags are normally in the        */
 /*      units of the coordinate system described.                       */
 /* -------------------------------------------------------------------- */
-    for( int iParam = 0; iParam < psDefn->nParms; iParam++ )
-    {
-        switch( psDefn->ProjParmId[iParam] )
-        {
           case ProjFalseEastingGeoKey:
           case ProjFalseNorthingGeoKey:
           case ProjFalseOriginEastingGeoKey:
@@ -2263,6 +2264,30 @@ static void GTIFFetchProjParms( GTIF * psGTIF, GTIFDefn * psDefn )
             }
             break;
 
+/* -------------------------------------------------------------------- */
+/*      Normalize any angular parameters into degrees.  In GeoTIFF      */
+/*      the angular projection parameter tags are normally in the       */
+/*      units of GeogAngularUnit. Note: this conversion is only done    */
+/*      since libgeotiff 1.7.4                                          */
+/* -------------------------------------------------------------------- */
+
+          case ProjStdParallel1GeoKey:
+          case ProjStdParallel2GeoKey:
+          case ProjNatOriginLongGeoKey:
+          case ProjNatOriginLatGeoKey:
+          case ProjFalseOriginLongGeoKey:
+          case ProjFalseOriginLatGeoKey:
+          case ProjCenterLongGeoKey:
+          case ProjCenterLatGeoKey:
+          case ProjStraightVertPoleLongGeoKey:
+          case ProjRectifiedGridAngleGeoKey:
+            if( psDefn->UOMAngleInDegrees != 0
+                && psDefn->UOMAngleInDegrees != 1.0 )
+            {
+                psDefn->ProjParm[iParam] *= psDefn->UOMAngleInDegrees;
+            }
+            break;
+
           default:
             break;
         }
diff --git a/frmts/gtiff/libgeotiff/geo_normalize.h b/frmts/gtiff/libgeotiff/geo_normalize.h
index 87dd22c7e7df..79f588c813b9 100644
--- a/frmts/gtiff/libgeotiff/geo_normalize.h
+++ b/frmts/gtiff/libgeotiff/geo_normalize.h
@@ -121,9 +121,15 @@ typedef struct {
     int		nParms;
 
     /** Projection parameter value.  The identify of this parameter
-        is established from the corresponding entry in ProjParmId.  The
-        value will be measured in meters, or decimal degrees if it is a
-        linear or angular measure. */
+        is established from the corresponding entry in ProjParmId.
+        In GeoTIFF keys, the values of the projection parameters are expressed
+        in the units of ProjLinearUnitsGeoKey (for linear measures) or
+        GeogAngularUnitsGeoKey (for angular measures).
+        However, the value returned in ProjParam[] will be normalized to meters
+        or decimal degrees.
+        Note: until libgeotiff 1.7.3, the conversion to degrees for angular
+        measures was *not* done when ProjCoordTransGeoKey is present.
+     */
     double	ProjParm[MAX_GTIF_PROJPARMS];
 
     /** Projection parameter identifier.  For example ProjFalseEastingGeoKey.
diff --git a/frmts/gtiff/libgeotiff/geotiff.h b/frmts/gtiff/libgeotiff/geotiff.h
index 29f22917f4c4..75de593c8a0e 100644
--- a/frmts/gtiff/libgeotiff/geotiff.h
+++ b/frmts/gtiff/libgeotiff/geotiff.h
@@ -47,7 +47,7 @@
 #define GEOTIFF_SPEC_1_1_MINOR_REVISION 1
 
 /* Library version */
-#define LIBGEOTIFF_VERSION 1710
+#define LIBGEOTIFF_VERSION 1740
 
 #include "geo_config.h"
 #include "geokeys.h"