WKT2 parsing: several fixes related to map projection parameter units

- WKT2 grammar: accept PARAMETER[name,value,id] without unit
- Recognize "Ellipsoid scaling factor" as a parameter with a scaling unit,
  and defaults to Unity when not specified
- WKT2 parsing: implement the requirement of 18-010r7.html#80, that is
  when a map projection parameter has no explicit unit, use metre/degree/unity
  as the default unit (contrary to WKT1 parsing rules where they are deduced
  from the GeogCRS angular unit and coordinate system)

1 files changed, 12 insertions, 3 deletions

diff --git a/src/iso19111/io.cpp b/src/iso19111/io.cpp
index b2e5822b..623ad6f9 100644
--- a/src/iso19111/io.cpp
+++ b/src/iso19111/io.cpp
@@ -2944,7 +2944,8 @@ UnitOfMeasure WKTParser::Private::guessUnitForParameter(
     const UnitOfMeasure &defaultAngularUnit) {
     UnitOfMeasure unit;
     // scale must be first because of 'Scale factor on pseudo standard parallel'
-    if (ci_find(paramName, "scale") != std::string::npos) {
+    if (ci_find(paramName, "scale") != std::string::npos ||
+        ci_find(paramName, "scaling factor") != std::string::npos) {
         unit = UnitOfMeasure::SCALE_UNITY;
     } else if (ci_find(paramName, "latitude") != std::string::npos ||
                ci_find(paramName, "longitude") != std::string::npos ||
@@ -3876,8 +3877,16 @@ WKTParser::Private::buildProjectedCRS(const WKTNodeNNPtr &node) {
         return createPseudoMercator(props, NN_NO_CHECK(cartesianCS));
     }
 
-    auto linearUnit = buildUnitInSubNode(node, UnitOfMeasure::Type::LINEAR);
-    auto angularUnit = baseGeodCRS->coordinateSystem()->axisList()[0]->unit();
+    // For WKT2, if there is no explicit parameter unit, use metre for linear
+    // units and degree for angular units
+    auto linearUnit =
+        !isNull(conversionNode)
+            ? UnitOfMeasure::METRE
+            : buildUnitInSubNode(node, UnitOfMeasure::Type::LINEAR);
+    auto angularUnit =
+        !isNull(conversionNode)
+            ? UnitOfMeasure::DEGREE
+            : baseGeodCRS->coordinateSystem()->axisList()[0]->unit();
 
     auto conversion =
         !isNull(conversionNode)