Export georeferencing to OCD more accurately

src/fileformats/ocd_file_export.cpp

@@ -943,21 +943,22 @@ void OcdFileExport::exportGeoreferencing()
 	{
 	case MapGrid::MillimetersOnMap:
 		grid_spacing_map = spacing;
-		grid_spacing_real = spacing * georef.getScaleDenominator()  / 1000;
+		grid_spacing_real = spacing * fields.m  / 1000;
 		break;
 	case MapGrid::MetersInTerrain:
-		grid_spacing_map = spacing * 1000 / georef.getScaleDenominator();
+		grid_spacing_map = spacing * 1000 / fields.m;
 		grid_spacing_real = spacing;
 		break;
 	}
 
 	QString string_1039;
 	QTextStream out(&string_1039, QIODevice::Append);
-	out << fixed
+	out << qSetRealNumberPrecision(6)
 	    << "\tm" << fields.m
 	    << qSetRealNumberPrecision(4)
 	    << "\tg" << grid_spacing_map
 	    << "\tr" << fields.r
+	    << qSetRealNumberPrecision(9)
 	    << "\tx" << fields.x
 	    << "\ty" << fields.y
 	    << qSetRealNumberPrecision(8)

src/fileformats/ocd_file_import.cpp

@@ -387,13 +387,25 @@ void OcdFileImport::importGeoreferencing(const QString& param_string)
 		switch (parameters.key())
 		{
 		case 'm':
-			tryParamConvert(fields.m, param_value);
+			{
+				auto scale_to_grid = param_value.toDouble(&ok);
+				if (ok)
+					fields.m = scale_to_grid;
+			}
 			break;
 		case 'x':
-			tryParamConvert(fields.x, param_value);
+			{
+				auto real_offset_x = param_value.toDouble(&ok);
+				if (ok)
+					fields.x = real_offset_x;
+			}
 			break;
 		case 'y':
-			tryParamConvert(fields.y, param_value);
+			{
+				auto real_offset_y = param_value.toDouble(&ok);
+				if (ok)
+					fields.y = real_offset_y;
+			}
 			break;
 		case 'i':
 			tryParamConvert(fields.i, param_value);

src/fileformats/ocd_georef_fields.cpp

@@ -838,25 +838,29 @@ int toOcd(const MapperCrs crs_unique_id,
 bool operator==(const OcdGeorefFields& lhs, const OcdGeorefFields& rhs)
 {
 	return lhs.i == rhs.i
-	        && lhs.m == rhs.m
-	        && lhs.x == rhs.x
-	        && lhs.y == rhs.y
+	        && ((qIsNaN(lhs.m) && qIsNaN(rhs.m)) || qAbs(lhs.m - rhs.m) < 5e-9) // 8-digit precision or both NaN's
+	        && ((qIsNaN(lhs.x) && qIsNaN(rhs.x)) || qAbs(lhs.x - rhs.x) < 5e-9) // 8-digit precision or both NaN's
+	        && ((qIsNaN(lhs.y) && qIsNaN(rhs.y)) || qAbs(lhs.y - rhs.y) < 5e-9) // 8-digit precision or both NaN's
 	        && ((qIsNaN(lhs.a) && qIsNaN(rhs.a)) || qAbs(lhs.a - rhs.a) < 5e-9) // 8-digit precision or both NaN's
 	        && lhs.r == rhs.r;
 }
 
 void OcdGeorefFields::setupGeoref(Georeferencing& georef,
                                   const std::function<void (const QString&)>& warning_handler) const
 {
-	if (m > 0)
-		georef.setScaleDenominator(m);
+	auto map_scale = qRound(m);
+	if (map_scale > 0)
+		georef.setScaleDenominator(map_scale);
 
 	if (r)
 		applyGridAndZone(georef, i, warning_handler);
 
 	QPointF proj_ref_point(x, y);
 	georef.setProjectedRefPoint(proj_ref_point, false, false);
-	georef.setCombinedScaleFactor(1.0);
+	if (m > 0)
+		georef.setCombinedScaleFactor(m / georef.getScaleDenominator());
+	else
+		georef.setCombinedScaleFactor(1.0);
 	georef.setGrivation(qIsFinite(a) ? a : 0);
 }
 
@@ -867,10 +871,10 @@ OcdGeorefFields OcdGeorefFields::fromGeoref(const Georeferencing& georef,
 
 	// store known values early, they can be useful even if CRS translation fails
 	retval.a = georef.getGrivation();
-	retval.m = georef.getScaleDenominator();
+	retval.m = georef.getScaleDenominator() * georef.getCombinedScaleFactor();
 	const QPointF offset(georef.toProjectedCoords(MapCoord{}));
-	retval.x = qRound(offset.x()); // OCD easting and northing is integer
-	retval.y = qRound(offset.y());
+	retval.x = offset.x();
+	retval.y = offset.y();
 
 	// attempt translation from Mapper CRS reference into OCD one
 	auto crs_id_string = georef.getProjectedCRSId();

src/fileformats/ocd_georef_fields.h

@@ -39,12 +39,12 @@ class Georeferencing;
  */
 struct OcdGeorefFields
 {
-	double a { 0 };  ///< Real world angle
-	int m { 15000 }, ///< Map scale
-	    x { 0 },     ///< Real world offset easting
-	    y { 0 },     ///< Real world offset northing
-	    i { 1000 },  ///< Grid and zone
-	    r { 0 };     ///< Real world coord (0 = paper, 1 = real world)
+	double a { 0 },     ///< Real world angle
+	       m { 15000 }, ///< Map scale, relative to grid
+	       x { 0 },     ///< Real world offset easting
+	       y { 0 };     ///< Real world offset northing
+	int i { 1000 },     ///< Grid and zone
+	    r { 0 };        ///< Real world coord (0 = paper, 1 = real world)
 
 	/**
 	 * Fill in provided georef with data extracted from type 1039 string.

test/georef_ocd_mapping_t.cpp

@@ -92,9 +92,9 @@ template<>
 char* toString(const OcdGeorefFields &f) // NOLINT : declared parameter name is 't'
 {
 	auto ret = QString(QStringLiteral("m:%1; x:%2; y:%3; a:%4; i:%5; r:%6"))
-	           .arg(f.m)
-	           .arg(f.x)
-	           .arg(f.y)
+	           .arg(f.m, 0, 'f', 3)
+	           .arg(f.x, 0, 'f', 2)
+	           .arg(f.y, 0, 'f', 2)
 	           .arg(f.a, 0, 'f', 8)
 	           .arg(f.i)
 	           .arg(f.r);