diff --git a/src/map/IMG/gmap.cpp b/src/map/IMG/gmap.cpp
index 4e16bb60..64a1e512 100644
--- a/src/map/IMG/gmap.cpp
+++ b/src/map/IMG/gmap.cpp
@@ -84,11 +84,13 @@ bool GMAP::loadTile(const QDir &dir, bool baseMap)
 		tile->addFile(fi.absoluteFilePath(), tileType(fi.suffix()));
 	}
 
-	if (!tile->init(baseMap)) {
+	if (!tile->init()) {
 		qWarning("%s: Invalid map tile", qPrintable(dir.path()));
 		delete tile;
 		return false;
 	}
+	if (baseMap)
+		tile->markAsBasemap();
 
 	double min[2], max[2];
 	min[0] = tile->bounds().left();
diff --git a/src/map/IMG/img.cpp b/src/map/IMG/img.cpp
index 7b577e3c..13c66d2f 100644
--- a/src/map/IMG/img.cpp
+++ b/src/map/IMG/img.cpp
@@ -132,11 +132,13 @@ IMG::IMG(const QString &fileName) : _file(fileName)
 	}
 
 	// Create tile tree
+
+	int minMapZoom = 24;
 	for (TileMap::const_iterator it = tileMap.constBegin();
 	  it != tileMap.constEnd(); ++it) {
 		VectorTile *tile = it.value();
 
-		if (!tile->init(false)) {
+		if (!tile->init()) {
 			qWarning("%s: %s: Invalid map tile", qPrintable(_file.fileName()),
 			  qPrintable(it.key()));
 			delete tile;
@@ -153,6 +155,17 @@ IMG::IMG(const QString &fileName) : _file(fileName)
 		_bounds |= tile->bounds();
 		if (tile->zooms().min() < _zooms.min())
 			_zooms.setMin(tile->zooms().min());
+		if (tile->zooms().min() < minMapZoom)
+			minMapZoom = tile->zooms().min();
+	}
+
+	for (TileMap::const_iterator it = tileMap.constBegin();
+	  it != tileMap.constEnd(); ++it) {
+		VectorTile *tile = it.value();
+		if (tile->zooms().min() > minMapZoom)
+			_baseMap = true;
+		if (tile->zooms().min() == minMapZoom)
+			tile->markAsBasemap();
 	}
 
 	if (!_tileTree.Count())
diff --git a/src/map/IMG/trefile.cpp b/src/map/IMG/trefile.cpp
index 6854cbf0..f258f5f4 100644
--- a/src/map/IMG/trefile.cpp
+++ b/src/map/IMG/trefile.cpp
@@ -42,12 +42,13 @@ TREFile::~TREFile()
 	clear();
 }
 
-bool TREFile::init(bool baseMap)
+bool TREFile::init()
 {
 	Handle hdl(this);
 	quint8 locked;
 	quint16 hdrLen;
 
+
 	if (!(seek(hdl, _gmpOffset) && readUInt16(hdl, hdrLen)
 	  && seek(hdl, _gmpOffset + 0x0D) && readUInt8(hdl, locked)))
 		return false;
@@ -114,7 +115,7 @@ bool TREFile::init(bool baseMap)
 		}
 	}
 
-	_isBaseMap = baseMap;
+	_isBaseMap = false;
 
 	return (_firstLevel >= 0);
 }
diff --git a/src/map/IMG/trefile.h b/src/map/IMG/trefile.h
index 2e252f73..b7fa4fd7 100644
--- a/src/map/IMG/trefile.h
+++ b/src/map/IMG/trefile.h
@@ -18,7 +18,8 @@ public:
 	TREFile(SubFile *gmp, quint32 offset) : SubFile(gmp, offset) {}
 	~TREFile();
 
-	bool init(bool baseMap);
+	bool init();
+	void markAsBasemap() {_isBaseMap = true;}
 	void clear();
 
 	const RectC &bounds() const {return _bounds;}
@@ -26,7 +27,7 @@ public:
 	quint32 shift(quint8 bits) const
 	  {return (bits == _levels.last().bits) ? (_flags >> 0xb) & 7 : 0;}
 	Range zooms() const
-	  {return Range(_levels.first().bits, _levels.last().bits);}
+	  {return Range(_levels.at(_firstLevel).bits, _levels.last().bits);}
 
 private:
 	struct MapLevel {
diff --git a/src/map/IMG/vectortile.cpp b/src/map/IMG/vectortile.cpp
index 2888789d..a8f948a7 100644
--- a/src/map/IMG/vectortile.cpp
+++ b/src/map/IMG/vectortile.cpp
@@ -82,12 +82,12 @@ SubFile *VectorTile::addFile(const QString &path, SubFile::Type type)
 	}
 }
 
-bool VectorTile::init(bool baseMap)
+bool VectorTile::init()
 {
 	if (_gmp && !initGMP())
 		return false;
 
-	if (!(_tre && _tre->init(baseMap) && _rgn))
+	if (!(_tre && _tre->init() && _rgn))
 		return false;
 
 	return true;
diff --git a/src/map/IMG/vectortile.h b/src/map/IMG/vectortile.h
index 26f27ac5..b63cf174 100644
--- a/src/map/IMG/vectortile.h
+++ b/src/map/IMG/vectortile.h
@@ -15,7 +15,8 @@ public:
 		delete _tre; delete _rgn; delete _lbl; delete _net; delete _gmp;
 	}
 
-	bool init(bool baseMap);
+	bool init();
+	void markAsBasemap() {_tre->markAsBasemap();}
 	void clear() {_tre->clear();}
 
 	const RectC &bounds() const {return _tre->bounds();}