diff --git a/src/common/garmin.h b/src/common/garmin.h
index 380a4fe6..487e2ff5 100644
--- a/src/common/garmin.h
+++ b/src/common/garmin.h
@@ -3,14 +3,16 @@
 
 #include <QtGlobal>
 
+#define LS(val, bits) ((qint32)(((quint32)(val))<<(bits)))
+
 inline double toWGS32(qint32 v)
 {
-	return (double)(((double)v / (double)(1U<<31)) * (double)180);
+	return ((double)v / (double)(1U<<31)) * 180.0;
 }
 
 inline double toWGS24(qint32 v)
 {
-	return toWGS32(v<<8);
+	return toWGS32(LS(v, 8));
 }
 
 #endif // GARMIN_H
diff --git a/src/map/IMG/rgnfile.cpp b/src/map/IMG/rgnfile.cpp
index 7221bfb6..6ae48f39 100644
--- a/src/map/IMG/rgnfile.cpp
+++ b/src/map/IMG/rgnfile.cpp
@@ -154,8 +154,8 @@ bool RGNFile::polyObjects(Handle &hdl, const SubDiv *subdiv,
 		  ? ((quint32)(type & 0x7F)) << 8 : ((quint32)(type & 0x3F)) << 8;
 
 
-		QPoint pos(subdiv->lon() + ((qint32)lon<<(24-subdiv->bits())),
-		  subdiv->lat() + ((qint32)lat<<(24-subdiv->bits())));
+		QPoint pos(subdiv->lon() + LS(lon, 24-subdiv->bits()),
+		  subdiv->lat() + LS(lat, 24-subdiv->bits()));
 		Coordinates c(toWGS24(pos.x()), toWGS24(pos.y()));
 		poly.boundingRect = RectC(c, c);
 		poly.points.append(QPointF(c.lon(), c.lat()));
@@ -164,8 +164,10 @@ bool RGNFile::polyObjects(Handle &hdl, const SubDiv *subdiv,
 		DeltaStream stream(*this, hdl, len, bitstreamInfo, labelPtr & 0x400000,
 		  false);
 		while (stream.readNext(lonDelta, latDelta)) {
-			pos.rx() += lonDelta<<(24-subdiv->bits());
-			pos.ry() += latDelta<<(24-subdiv->bits());
+			pos.rx() += LS(lonDelta, (24-subdiv->bits()));
+			if (pos.rx() >= 0x800000 && subdiv->lon() >= 0)
+				pos.rx() = 0x7fffff;
+			pos.ry() += LS(latDelta, (24-subdiv->bits()));
 
 			Coordinates c(toWGS24(pos.x()), toWGS24(pos.y()));
 			poly.points.append(QPointF(c.lon(), c.lat()));
@@ -219,8 +221,8 @@ bool RGNFile::extPolyObjects(Handle &hdl, const SubDiv *subdiv, quint32 shift,
 		labelPtr = 0;
 
 		if (!_huffmanTable.isNull()) {
-			pos = QPoint((subdiv->lon()<<8) + ((qint32)lon<<(32-subdiv->bits())),
-			  (subdiv->lat()<<8) + ((qint32)lat<<(32-subdiv->bits())));
+			pos = QPoint(LS(subdiv->lon(), 8) + LS(lon, 32-subdiv->bits()),
+			  LS(subdiv->lat(), 8) + LS(lat, (32-subdiv->bits())));
 
 			qint32 lonDelta, latDelta;
 			HuffmanStream stream(*this, hdl, len, _huffmanTable,
@@ -229,16 +231,18 @@ bool RGNFile::extPolyObjects(Handle &hdl, const SubDiv *subdiv, quint32 shift,
 			if (shift) {
 				if (!stream.readOffset(lonDelta, latDelta))
 					return false;
-				pos = QPoint(pos.x() | lonDelta<<(32-subdiv->bits()-shift),
-				  pos.y() | latDelta<<(32-subdiv->bits()-shift));
+				pos = QPoint(pos.x() | LS(lonDelta, 32-subdiv->bits()-shift),
+				  pos.y() | LS(latDelta, 32-subdiv->bits()-shift));
 			}
 			Coordinates c(toWGS32(pos.x()), toWGS32(pos.y()));
 			poly.boundingRect = RectC(c, c);
 			poly.points.append(QPointF(c.lon(), c.lat()));
 
 			while (stream.readNext(lonDelta, latDelta)) {
-				pos.rx() += lonDelta<<(32-subdiv->bits()-shift);
-				pos.ry() += latDelta<<(32-subdiv->bits()-shift);
+				pos.rx() += LS(lonDelta, 32-subdiv->bits()-shift);
+				if (pos.rx() < 0 && subdiv->lon() >= 0)
+					pos.rx() = 0x7fffffff;
+				pos.ry() += LS(latDelta, 32-subdiv->bits()-shift);
 
 				Coordinates c(toWGS32(pos.x()), toWGS32(pos.y()));
 				poly.points.append(QPointF(c.lon(), c.lat()));
@@ -248,8 +252,8 @@ bool RGNFile::extPolyObjects(Handle &hdl, const SubDiv *subdiv, quint32 shift,
 			if (!(stream.atEnd() && stream.flush()))
 				return false;
 		} else {
-			pos = QPoint(subdiv->lon() + ((qint32)lon<<(24-subdiv->bits())),
-			  subdiv->lat() + ((qint32)lat<<(24-subdiv->bits())));
+			pos = QPoint(subdiv->lon() + LS(lon, 24-subdiv->bits()),
+			  subdiv->lat() + LS(lat, 24-subdiv->bits()));
 			Coordinates c(toWGS24(pos.x()), toWGS24(pos.y()));
 			poly.boundingRect = RectC(c, c);
 			poly.points.append(QPointF(c.lon(), c.lat()));
@@ -262,8 +266,10 @@ bool RGNFile::extPolyObjects(Handle &hdl, const SubDiv *subdiv, quint32 shift,
 			DeltaStream stream(*this, hdl, len - 1, bitstreamInfo, false, true);
 
 			while (stream.readNext(lonDelta, latDelta)) {
-				pos.rx() += lonDelta<<(24-subdiv->bits());
-				pos.ry() += latDelta<<(24-subdiv->bits());
+				pos.rx() += LS(lonDelta, 24-subdiv->bits());
+				if (pos.rx() >= 0x800000 && subdiv->lon() >= 0)
+					pos.rx() = 0x7fffff;
+				pos.ry() += LS(latDelta, 24-subdiv->bits());
 
 				Coordinates c(toWGS24(pos.x()), toWGS24(pos.y()));
 				poly.points.append(QPointF(c.lon(), c.lat()));
@@ -319,8 +325,8 @@ bool RGNFile::pointObjects(Handle &hdl, const SubDiv *subdiv,
 
 		point.type = (quint16)type<<8 | subtype;
 
-		qint32 lonOffset = lon<<(24-subdiv->bits());
-		qint32 latOffset = lat<<(24-subdiv->bits());
+		qint32 lonOffset = LS(lon, 24-subdiv->bits());
+		qint32 latOffset = LS(lat, 24-subdiv->bits());
 		point.coordinates = Coordinates(toWGS24(subdiv->lon() + lonOffset),
 		  toWGS24(subdiv->lat() + latOffset));
 
@@ -361,8 +367,8 @@ bool RGNFile::extPointObjects(Handle &hdl, const SubDiv *subdiv, LBLFile *lbl,
 
 		point.type = 0x10000 | (((quint32)type)<<8) | (subtype & 0x1F);
 
-		qint32 lonOffset = lon<<(24-subdiv->bits());
-		qint32 latOffset = lat<<(24-subdiv->bits());
+		qint32 lonOffset = LS(lon, 24-subdiv->bits());
+		qint32 latOffset = LS(lat, 24-subdiv->bits());
 		point.coordinates = Coordinates(toWGS24(subdiv->lon() + lonOffset),
 		  toWGS24(subdiv->lat() + latOffset));
 		labelPtr = 0;
diff --git a/src/map/IMG/trefile.cpp b/src/map/IMG/trefile.cpp
index 53df9ae3..6854cbf0 100644
--- a/src/map/IMG/trefile.cpp
+++ b/src/map/IMG/trefile.cpp
@@ -3,6 +3,11 @@
 #include "trefile.h"
 
 
+static inline double RB(qint32 val)
+{
+	return (val == -0x800000 || val == 0x800000) ? 180.0 : toWGS24(val);
+}
+
 static void demangle(quint8 *data, quint32 size, quint32 key)
 {
 	static const unsigned char shuf[] = {
@@ -53,7 +58,8 @@ bool TREFile::init(bool baseMap)
 	  && readInt24(hdl, east) && readInt24(hdl, south) && readInt24(hdl, west)))
 		return false;
 	_bounds = RectC(Coordinates(toWGS24(west), toWGS24(north)),
-	  Coordinates(toWGS24(east), toWGS24(south)));
+	  Coordinates(RB(east), toWGS24(south)));
+	Q_ASSERT(_bounds.left() <= _bounds.right());
 
 	// Levels & subdivs info
 	quint32 levelsOffset, levelsSize, subdivSize;
@@ -149,17 +155,16 @@ bool TREFile::load(int idx)
 			s->setEnd(offset);
 
 		width &= 0x7FFF;
-		width <<= (24 - _levels.at(idx).bits);
-		height <<= (24 - _levels.at(idx).bits);
-
+		width = LS(width, 24 - _levels.at(idx).bits);
+		height = LS(height, 24 - _levels.at(idx).bits);
 
 		s = new SubDiv(offset, lon, lat, _levels.at(idx).bits, objects);
 		sl.append(s);
 
 		double min[2], max[2];
-		RectC bounds(Coordinates(toWGS24(lon - width),
-		  toWGS24(lat + height + 1)), Coordinates(toWGS24(lon + width + 1),
-		  toWGS24(lat - height)));
+		RectC bounds(Coordinates(toWGS24(lon - width), toWGS24(lat + height)),
+		  Coordinates(RB(lon + width), toWGS24(lat - height)));
+		Q_ASSERT(bounds.left() <= bounds.right());
 
 		min[0] = bounds.left();
 		min[1] = bounds.bottom();