diff --git a/src/map/aqmmap.cpp b/src/map/aqmmap.cpp
index 5b06f1b5..c07c9d9a 100644
--- a/src/map/aqmmap.cpp
+++ b/src/map/aqmmap.cpp
@@ -191,8 +191,23 @@ bool AQMMap::readHeader()
 			if (!parseLevel(data, zoom, tileSize, bounds))
 				return false;
 
-			_bounds = RectC(OSM::tile2ll(bounds.topLeft(), zoom),
-			  OSM::tile2ll(bounds.bottomRight(), zoom));
+			if (_bounds.isNull()) {
+				double minX = OSM::index2mercator(qMin((1<<zoom) - 1,
+				  qMax(0, bounds.left())), zoom);
+				double minY = OSM::index2mercator(qMin((1<<zoom) - 1,
+				  qMax(0, bounds.top())), zoom);
+				double maxX = OSM::index2mercator(qMin((1<<zoom) - 1,
+				  qMax(0, bounds.right())) + 1, zoom);
+				double maxY = OSM::index2mercator(qMin((1<<zoom) - 1,
+				  qMax(0, bounds.bottom())) + 1, zoom);
+				Coordinates tl(OSM::m2ll(QPointF(minX, -minY)));
+				Coordinates br(OSM::m2ll(QPointF(maxX, -maxY)));
+				// Workaround of broken zoom levels 0 and 1 due to numerical
+				// instability
+				tl.rlat() = qMin(tl.lat(), OSM::BOUNDS.top());
+				br.rlat() = qMax(br.lat(), OSM::BOUNDS.bottom());
+				_bounds = RectC(tl, br);
+			}
 			_zooms.append(Zoom(zoom, tileSize));
 		} else if (files.at(i).name == "@LEVEL") {
 			li = i;
@@ -353,16 +368,20 @@ void AQMMap::draw(QPainter *painter, const QRectF &rect, Flags flags)
 	Q_UNUSED(flags);
 	const Zoom &z = _zooms.at(_zoom);
 	qreal scale = OSM::zoom2scale(z.zoom, z.tileSize);
+	QRectF b(bounds());
+
 
 	QPoint tile = OSM::mercator2tile(QPointF(rect.topLeft().x() * scale,
 	  -rect.topLeft().y() * scale) * _mapRatio, z.zoom);
 	QPointF tl(floor(rect.left() / tileSize())
 	  * tileSize(), floor(rect.top() / tileSize()) * tileSize());
 
-	QSizeF s(rect.right() - tl.x(), rect.bottom() - tl.y());
+	QSizeF s(qMin(rect.right() - tl.x(), b.width()),
+	  qMin(rect.bottom() - tl.y(), b.height()));
 	int width = ceil(s.width() / tileSize());
 	int height = ceil(s.height() / tileSize());
 
+
 	QList<AQTile> tiles;
 
 	for (int i = 0; i < width; i++) {
@@ -373,11 +392,13 @@ void AQMMap::draw(QPainter *painter, const QRectF &rect, Flags flags)
 			  + QString::number(t.x()) + "_" + QString::number(t.y());
 
 			if (QPixmapCache::find(key, &pm)) {
-				QPointF tp(tl.x() + (t.x() - tile.x()) * tileSize(),
-				  tl.y() + (t.y() - tile.y()) * tileSize());
+				QPointF tp(qMax(tl.x(), b.left()) + (t.x() - tile.x())
+				  * tileSize(), qMax(tl.y(), b.top()) + (t.y() - tile.y())
+				  * tileSize());
 				drawTile(painter, pm, tp);
-			} else
+			} else {
 				tiles.append(AQTile(t, tileData(t), key));
+			}
 		}
 	}
 
@@ -389,10 +410,12 @@ void AQMMap::draw(QPainter *painter, const QRectF &rect, Flags flags)
 		QPixmap pm(mt.pixmap());
 		if (pm.isNull())
 			continue;
+
 		QPixmapCache::insert(mt.key(), pm);
 
-		QPointF tp(tl.x() + (mt.xy().x() - tile.x()) * tileSize(),
-		  tl.y() + (mt.xy().y() - tile.y()) * tileSize());
+		QPointF tp(qMax(tl.x(), b.left()) + (mt.xy().x() - tile.x())
+		  * tileSize(), qMax(tl.y(), b.top()) + (mt.xy().y() - tile.y())
+		  * tileSize());
 		drawTile(painter, pm, tp);
 	}
 }
diff --git a/src/map/aqmmap.h b/src/map/aqmmap.h
index 06b3ef4f..f1f0f86e 100644
--- a/src/map/aqmmap.h
+++ b/src/map/aqmmap.h
@@ -18,6 +18,7 @@ public:
 	QString name() const {return _name;}
 
 	QRectF bounds();
+	RectC llBounds() {return _bounds;}
 	qreal resolution(const QRectF &rect);
 
 	int zoom() const {return _zoom;}
diff --git a/src/map/mbtilesmap.cpp b/src/map/mbtilesmap.cpp
index 34a82205..0a9732b9 100644
--- a/src/map/mbtilesmap.cpp
+++ b/src/map/mbtilesmap.cpp
@@ -1,18 +1,18 @@
 #include <QSqlQuery>
 #include <QSqlRecord>
 #include <QSqlField>
-#include <QFileInfo>
 #include <QPainter>
 #include <QPixmapCache>
 #include <QImageReader>
 #include <QBuffer>
 #include <QtConcurrent>
-#include "common/rectc.h"
 #include "common/util.h"
 #include "osm.h"
 #include "mbtilesmap.h"
 
 
+#define META_TYPE(type) static_cast<QMetaType::Type>(type)
+
 class MBTile
 {
 public:
@@ -43,12 +43,6 @@ private:
 	QImage _image;
 };
 
-#define META_TYPE(type) static_cast<QMetaType::Type>(type)
-
-static double index2mercator(int index, int zoom)
-{
-	return rad2deg(-M_PI + 2 * M_PI * ((double)index / (1<<zoom)));
-}
 
 MBTilesMap::MBTilesMap(const QString &fileName, QObject *parent)
   : Map(fileName, parent), _mapRatio(1.0), _tileRatio(1.0), _scalable(false),
@@ -59,7 +53,7 @@ MBTilesMap::MBTilesMap(const QString &fileName, QObject *parent)
 	_db.setConnectOptions("QSQLITE_OPEN_READONLY");
 
 	if (!_db.open()) {
-		_errorString = fileName + ": Error opening database file";
+		_errorString = "Error opening database file";
 		return;
 	}
 
@@ -99,13 +93,13 @@ MBTilesMap::MBTilesMap(const QString &fileName, QObject *parent)
 		QSqlQuery query(sql, _db);
 		query.first();
 
-		double minX = index2mercator(qMin((1<<_zooms.min()) - 1,
+		double minX = OSM::index2mercator(qMin((1<<_zooms.min()) - 1,
 		  qMax(0, query.value(0).toInt())), _zooms.min());
-		double minY = index2mercator(qMin((1<<_zooms.min()) - 1,
+		double minY = OSM::index2mercator(qMin((1<<_zooms.min()) - 1,
 		  qMax(0, query.value(1).toInt())), _zooms.min());
-		double maxX = index2mercator(qMin((1<<_zooms.min()) - 1,
+		double maxX = OSM::index2mercator(qMin((1<<_zooms.min()) - 1,
 		  qMax(0, query.value(2).toInt())) + 1, _zooms.min());
-		double maxY = index2mercator(qMin((1<<_zooms.min()) - 1,
+		double maxY = OSM::index2mercator(qMin((1<<_zooms.min()) - 1,
 		  qMax(0, query.value(3).toInt())) + 1, _zooms.min());
 		Coordinates tl(OSM::m2ll(QPointF(minX, maxY)));
 		Coordinates br(OSM::m2ll(QPointF(maxX, minY)));
diff --git a/src/map/mbtilesmap.h b/src/map/mbtilesmap.h
index 75c4e535..951e08c1 100644
--- a/src/map/mbtilesmap.h
+++ b/src/map/mbtilesmap.h
@@ -2,7 +2,6 @@
 #define MBTILESMAP_H
 
 #include <QSqlDatabase>
-#include <QByteArray>
 #include "common/range.h"
 #include "map.h"
 
diff --git a/src/map/osm.cpp b/src/map/osm.cpp
index c12480eb..e090f97b 100644
--- a/src/map/osm.cpp
+++ b/src/map/osm.cpp
@@ -21,11 +21,9 @@ QPoint OSM::mercator2tile(const QPointF &m, int zoom)
 	  qFloor((1.0 - (m.y() / 180.0)) / 2.0 * (1<<zoom)));
 }
 
-Coordinates OSM::tile2ll(const QPoint &p, int z)
+double OSM::index2mercator(int index, int zoom)
 {
-	double n = M_PI - 2.0 * M_PI * p.y() / (double)(1 << z);
-	return Coordinates(p.x() / (double)(1 << z) * 360.0 - 180,
-	  180.0 / M_PI * atan(0.5 * (exp(n) - exp(-n))));
+	return rad2deg(-M_PI + 2 * M_PI * ((double)index / (1<<zoom)));
 }
 
 qreal OSM::zoom2scale(int zoom, int tileSize)
diff --git a/src/map/osm.h b/src/map/osm.h
index 5a1c13f5..cba3cb1b 100644
--- a/src/map/osm.h
+++ b/src/map/osm.h
@@ -15,7 +15,7 @@ namespace OSM
 	QPointF ll2m(const Coordinates &c);
 	Coordinates m2ll(const QPointF &p);
 	QPoint mercator2tile(const QPointF &m, int zoom);
-	Coordinates tile2ll(const QPoint &p, int z);
+	double index2mercator(int index, int zoom);
 	qreal zoom2scale(int zoom, int tileSize);
 	int scale2zoom(qreal scale, int tileSize);
 	qreal resolution(const QPointF &p, int zoom, int tileSize);