diff --git a/gpxsee.pro b/gpxsee.pro
index 78529daf..40c00b92 100644
--- a/gpxsee.pro
+++ b/gpxsee.pro
@@ -10,7 +10,6 @@ HEADERS += src/config.h \
     src/gui.h \
     src/poi.h \
     src/rtree.h \
-    src/ll.h \
     src/axisitem.h \
     src/keys.h \
     src/slideritem.h \
@@ -56,11 +55,14 @@ HEADERS += src/config.h \
     src/gpxparser.h \
     src/tcxparser.h \
     src/parser.h \
-    src/csvparser.h
+    src/csvparser.h \
+    src/coordinates.h \
+    src/tile.h \
+    src/rd.h \
+    src/wgs84.h
 SOURCES += src/main.cpp \
     src/gui.cpp \
     src/poi.cpp \
-    src/ll.cpp \
     src/axisitem.cpp \
     src/slideritem.cpp \
     src/markeritem.cpp \
@@ -98,7 +100,8 @@ SOURCES += src/main.cpp \
     src/data.cpp \
     src/gpxparser.cpp \
     src/tcxparser.cpp \
-    src/csvparser.cpp
+    src/csvparser.cpp \
+    src/coordinates.cpp
 RESOURCES += gpxsee.qrc
 TRANSLATIONS = lang/gpxsee_cs.ts
 macx {
diff --git a/src/coordinates.cpp b/src/coordinates.cpp
new file mode 100644
index 00000000..200ac03b
--- /dev/null
+++ b/src/coordinates.cpp
@@ -0,0 +1,42 @@
+#include "rd.h"
+#include "wgs84.h"
+#include "coordinates.h"
+
+bool Coordinates::isValid() const
+{
+	return (_lon >= -180.0 && _lon <= 180.0 && _lat >= -90.0 && _lat <= 90.0)
+	  ? true : false;
+}
+
+qreal Coordinates::distanceTo(const Coordinates &c) const
+{
+	qreal dLat = deg2rad(c.lat() - _lat);
+	qreal dLon = deg2rad(c.lon() - _lon);
+	qreal a = pow(sin(dLat / 2.0), 2.0)
+	  + cos(deg2rad(_lat)) * cos(deg2rad(c.lat())) * pow(sin(dLon / 2.0), 2.0);
+
+	return (WGS84_RADIUS * (2.0 * atan2(sqrt(a), sqrt(1.0 - a))));
+}
+
+QPointF Coordinates::toMercator() const
+{
+	return QPointF(_lon, rad2deg(log(tan(M_PI/4.0 + deg2rad(_lat)/2.0))));
+}
+
+Coordinates Coordinates::fromMercator(const QPointF &m)
+{
+	return Coordinates(m.x(), rad2deg(2 * atan(exp(deg2rad(m.y()))) - M_PI/2));
+}
+
+bool operator==(const Coordinates &c1, const Coordinates &c2)
+{
+	return (c1.lat() == c2.lat() && c1.lon() == c2.lon());
+}
+
+QDebug operator<<(QDebug dbg, const Coordinates &coordinates)
+{
+	dbg.nospace() << "Coordinates(" << coordinates.lon() << ", "
+	  << coordinates.lat() << ")";
+
+	return dbg.maybeSpace();
+}
diff --git a/src/coordinates.h b/src/coordinates.h
new file mode 100644
index 00000000..d979d5c8
--- /dev/null
+++ b/src/coordinates.h
@@ -0,0 +1,35 @@
+#ifndef COORDINATES_H
+#define COORDINATES_H
+
+#include <cmath>
+#include <QPointF>
+#include <QDebug>
+
+class Coordinates
+{
+public:
+	Coordinates() {_lon = NAN; _lat = NAN;}
+	Coordinates(const Coordinates &c) {_lon = c._lon; _lat = c._lat;}
+	Coordinates(qreal lon, qreal lat) {_lon = lon; _lat = lat;}
+
+	qreal &rLon() {return _lon;}
+	qreal &rLat() {return _lat;}
+	void setLon(qreal lon) {_lon = lon;}
+	void setLat(qreal lat) {_lat = lat;}
+	qreal lon() const {return _lon;}
+	qreal lat() const {return _lat;}
+
+	bool isValid() const;
+	qreal distanceTo(const Coordinates &c) const;
+
+	QPointF toMercator() const;
+	static Coordinates fromMercator(const QPointF &m);
+
+private:
+	qreal _lat, _lon;
+};
+
+bool operator==(const Coordinates &c1, const Coordinates &c2);
+QDebug operator<<(QDebug dbg, const Coordinates &trackpoint);
+
+#endif // COORDINATES_H
diff --git a/src/csvparser.cpp b/src/csvparser.cpp
index 132b3d18..b9179a22 100644
--- a/src/csvparser.cpp
+++ b/src/csvparser.cpp
@@ -29,7 +29,7 @@ bool CSVParser::loadFile(QIODevice *device)
 			_errorLine = ln;
 			return false;
 		}
-		Waypoint wp(QPointF(lon, lat));
+		Waypoint wp(Coordinates(lon, lat));
 
 		QByteArray ba = list[2].trimmed();
 		QString name = QString::fromUtf8(ba.data(), ba.size());
diff --git a/src/data.cpp b/src/data.cpp
index cb1c3165..3cf218cd 100644
--- a/src/data.cpp
+++ b/src/data.cpp
@@ -1,6 +1,5 @@
-#include <QFile>
+#include <QFile>
 #include <QLineF>
-#include "ll.h"
 #include "gpxparser.h"
 #include "tcxparser.h"
 #include "csvparser.h"
diff --git a/src/gpxparser.cpp b/src/gpxparser.cpp
index 6a17db70..52418249 100644
--- a/src/gpxparser.cpp
+++ b/src/gpxparser.cpp
@@ -76,25 +76,38 @@ void GPXParser::handleRoutepointData(DataType type, const QString &value)
 	}
 }
 
+Coordinates GPXParser::coordinates(const QXmlStreamAttributes &attr)
+{
+	bool res;
+	qreal lon, lat;
+
+	lon = attr.value("lon").toDouble(&res);
+	if (!res || (lon < -180.0 || lon > 180.0)) {
+		_reader.raiseError("Invalid longitude.");
+		return Coordinates();
+	}
+	lat = attr.value("lat").toDouble(&res);
+	if (!res || (lat < -90.0 || lat > 90.0)) {
+		_reader.raiseError("Invalid latitude.");
+		return Coordinates();
+	}
+
+	return Coordinates(lon, lat);
+}
+
 void GPXParser::handleTrackpointAttributes(const QXmlStreamAttributes &attr)
 {
-	_track->last().setCoordinates(QPointF(
-	  attr.value("lon").toDouble(),
-	  attr.value("lat").toDouble()));
+	_track->last().setCoordinates(coordinates(attr));
 }
 
 void GPXParser::handleRoutepointAttributes(const QXmlStreamAttributes &attr)
 {
-	_route->last().setCoordinates(QPointF(
-	  attr.value("lon").toDouble(),
-	  attr.value("lat").toDouble()));
+	_route->last().setCoordinates(coordinates(attr));
 }
 
 void GPXParser::handleWaypointAttributes(const QXmlStreamAttributes &attr)
 {
-	_waypoints.last().setCoordinates(QPointF(
-	  attr.value("lon").toDouble(),
-	  attr.value("lat").toDouble()));
+	_waypoints.last().setCoordinates(coordinates(attr));
 }
 
 void GPXParser::tpExtension()
diff --git a/src/gpxparser.h b/src/gpxparser.h
index c6c7a437..3121d3e3 100644
--- a/src/gpxparser.h
+++ b/src/gpxparser.h
@@ -36,6 +36,8 @@ private:
 	void routepointData();
 	void waypointData();
 
+	Coordinates coordinates(const QXmlStreamAttributes &attr);
+
 	void handleWaypointAttributes(const QXmlStreamAttributes &attr);
 	void handleWaypointData(DataType type, const QString &value);
 	void handleTrackpointAttributes(const QXmlStreamAttributes &attr);
diff --git a/src/ll.cpp b/src/ll.cpp
deleted file mode 100644
index f4e39039..00000000
--- a/src/ll.cpp
+++ /dev/null
@@ -1,86 +0,0 @@
-#include <cmath>
-#include "ll.h"
-
-// MSVC workarounds
-#ifndef M_PI
-	#define M_PI 3.14159265358979323846
-#endif // M_PI
-#if defined(_MSC_VER) && (_MSC_VER < 1800)
-	#define log2(n) (log(n)/log(2.0))
-#endif
-
-
-#define WGS84_RADIUS 6378137.0
-#define deg2rad(d) (((d)*M_PI)/180.0)
-#define rad2deg(d) (((d)*180.0)/M_PI)
-
-qreal llDistance(const QPointF &p1, const QPointF &p2)
-{
-	qreal dLat = deg2rad(p2.y() - p1.y());
-	qreal dLon = deg2rad(p2.x() - p1.x());
-	qreal a = pow(sin(dLat / 2.0), 2.0)
-	  + cos(deg2rad(p1.y())) * cos(deg2rad(p2.y())) * pow(sin(dLon / 2.0), 2.0);
-	qreal c = 2.0 * atan2(sqrt(a), sqrt(1.0 - a));
-
-	return (WGS84_RADIUS * c);
-}
-
-QPointF ll2mercator(const QPointF &ll)
-{
-	QPointF m;
-
-	m.setX(ll.x());
-	m.setY(rad2deg(log(tan(M_PI/4.0 + deg2rad(ll.y())/2.0))));
-
-	return m;
-}
-
-QPointF mercator2ll(const QPointF &m)
-{
-	QPointF ll;
-
-	ll.setX(m.x());
-	ll.setY(rad2deg(2 * atan(exp(deg2rad(m.y()))) - M_PI/2));
-
-	return ll;
-}
-
-QPoint mercator2tile(const QPointF &m, int z)
-{
-	QPoint tile;
-
-	tile.setX((int)(floor((m.x() + 180.0) / 360.0 * pow(2.0, z))));
-	tile.setY((int)(floor((1.0 - (m.y() / 180.0)) / 2.0 * pow(2.0, z))));
-
-	return tile;
-}
-
-QPointF tile2mercator(const QPoint &tile, int z)
-{
-	QPointF m;
-
-	m.setX(tile.x() / pow(2.0, z) * 360.0 - 180);
-	qreal n = M_PI - 2.0 * M_PI * tile.y() / pow(2.0, z);
-	m.setY(rad2deg(atan(0.5 * (exp(n) - exp(-n)))));
-
-	return ll2mercator(m);
-}
-
-int scale2zoom(qreal scale)
-{
-	int zoom;
-
-	zoom = (int)log2(360.0/(scale * (qreal)TILE_SIZE));
-
-	if (zoom < ZOOM_MIN)
-		return ZOOM_MIN;
-	if (zoom > ZOOM_MAX)
-		return ZOOM_MAX;
-	return zoom;
-}
-
-qreal zoom2resolution(int zoom, qreal y)
-{
-	return (WGS84_RADIUS * 2 * M_PI / 256 * cos(2 * atan(exp(deg2rad(y)))
-	  - M_PI/2)) / pow(2.0, zoom);
-}
diff --git a/src/ll.h b/src/ll.h
deleted file mode 100644
index e84575d2..00000000
--- a/src/ll.h
+++ /dev/null
@@ -1,18 +0,0 @@
-#ifndef LL_H
-#define LL_H
-
-#include <QPointF>
-
-#define TILE_SIZE 256
-#define ZOOM_MAX 18
-#define ZOOM_MIN 3
-
-QPointF ll2mercator(const QPointF &ll);
-QPointF mercator2ll(const QPointF &m);
-qreal llDistance(const QPointF &p1, const QPointF &p2);
-QPoint mercator2tile(const QPointF &m, int zoom);
-QPointF tile2mercator(const QPoint &tile, int zoom);
-int scale2zoom(qreal scale);
-qreal zoom2resolution(int zoom, qreal y);
-
-#endif // LL_H
diff --git a/src/map.cpp b/src/map.cpp
index 52883390..f86ad550 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -1,7 +1,6 @@
 #include <QFileInfo>
 #include <QDir>
 #include "downloader.h"
-#include "ll.h"
 #include "config.h"
 #include "map.h"
 
@@ -91,7 +90,7 @@ void Map::loadTilesSync(QList<Tile> &list)
 
 void Map::fillTile(Tile &tile)
 {
-	tile.pixmap() = QPixmap(TILE_SIZE, TILE_SIZE);
+	tile.pixmap() = QPixmap(Tile::size(), Tile::size());
 	tile.pixmap().fill();
 }
 
diff --git a/src/map.h b/src/map.h
index 63300832..cbd84333 100644
--- a/src/map.h
+++ b/src/map.h
@@ -1,24 +1,7 @@
 #ifndef MAP_H
 #define MAP_H
 
-#include <QPixmap>
-
-class Tile
-{
-public:
-	Tile(const QPoint &xy, int zoom)
-		{_xy = xy; _zoom = zoom;}
-
-	int zoom() const {return _zoom;}
-	const QPoint& xy() const {return _xy;}
-	QPixmap& pixmap() {return _pixmap;}
-
-private:
-	int _zoom;
-	QPoint _xy;
-	QPixmap _pixmap;
-};
-
+#include "tile.h"
 
 class Map : public QObject
 {
diff --git a/src/misc.cpp b/src/misc.cpp
index f3a68376..6b0bfafe 100644
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -76,11 +76,11 @@ QString elevation(qreal value, Units units)
 		  + qApp->translate("Misc", "ft");
 }
 
-QString coordinates(const QPointF &value)
+QString coordinates(const Coordinates &value)
 {
-	QChar yH = (value.y() < 0) ? 'S' : 'N';
-	QChar xH = (value.x() < 0) ? 'W' : 'E';
+	QChar yH = (value.lat() < 0) ? 'S' : 'N';
+	QChar xH = (value.lon() < 0) ? 'W' : 'E';
 
-	return QString::number(qAbs(value.y()), 'f', 5) + yH + "," + QChar(0x00A0)
-	  + QString::number(qAbs(value.x()), 'f', 5) + xH;
+	return QString::number(qAbs(value.lat()), 'f', 5) + yH + "," + QChar(0x00A0)
+	  + QString::number(qAbs(value.lon()), 'f', 5) + xH;
 }
diff --git a/src/misc.h b/src/misc.h
index c07cb191..0de66ddf 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -3,6 +3,7 @@
 
 #include <QString>
 #include <QPoint>
+#include "coordinates.h"
 #include "units.h"
 
 double niceNum(double x, int round);
@@ -10,6 +11,6 @@ double niceNum(double x, int round);
 QString timeSpan(qreal time);
 QString distance(qreal value, Units units);
 QString elevation(qreal value, Units units);
-QString coordinates(const QPointF &value);
+QString coordinates(const Coordinates &value);
 
 #endif // MISC_H
diff --git a/src/pathview.cpp b/src/pathview.cpp
index f7acbc0b..b63da690 100644
--- a/src/pathview.cpp
+++ b/src/pathview.cpp
@@ -1,7 +1,7 @@
 #include <QGraphicsView>
 #include <QGraphicsScene>
 #include <QWheelEvent>
-#include "ll.h"
+#include "rd.h"
 #include "poi.h"
 #include "data.h"
 #include "map.h"
@@ -12,8 +12,43 @@
 #include "pathview.h"
 
 
-#define MARGIN          10.0
-#define SCALE_OFFSET    7
+#define ZOOM_MAX      18
+#define ZOOM_MIN      3
+#define MARGIN        10.0
+#define SCALE_OFFSET  7
+
+static QPoint mercator2tile(const QPointF &m, int z)
+{
+	QPoint tile;
+
+	tile.setX((int)(floor((m.x() + 180.0) / 360.0 * pow(2.0, z))));
+	tile.setY((int)(floor((1.0 - (m.y() / 180.0)) / 2.0 * pow(2.0, z))));
+
+	return tile;
+}
+
+static QPointF tile2mercator(const QPoint &tile, int z)
+{
+	Coordinates m;
+
+	m.setLon(tile.x() / pow(2.0, z) * 360.0 - 180);
+	qreal n = M_PI - 2.0 * M_PI * tile.y() / pow(2.0, z);
+	m.setLat(rad2deg(atan(0.5 * (exp(n) - exp(-n)))));
+
+	return m.toMercator();
+}
+
+static int scale2zoom(qreal scale)
+{
+	int zoom = (int)log2(360.0/(scale * (qreal)Tile::size()));
+
+	if (zoom < ZOOM_MIN)
+		return ZOOM_MIN;
+	if (zoom > ZOOM_MAX)
+		return ZOOM_MAX;
+
+	return zoom;
+}
 
 PathView::PathView(QWidget *parent)
 	: QGraphicsView(parent)
@@ -147,7 +182,8 @@ QList<PathItem *> PathView::loadData(const Data &data)
 
 	QRectF br = trackBoundingRect() | routeBoundingRect()
 	  | waypointBoundingRect();
-	QRectF ba = br.adjusted(-TILE_SIZE, -TILE_SIZE, TILE_SIZE, TILE_SIZE);
+	QRectF ba = br.adjusted(-Tile::size(), -Tile::size(), Tile::size(),
+	  Tile::size());
 	_scene->setSceneRect(ba);
 	centerOn(ba.center());
 
@@ -268,7 +304,7 @@ qreal PathView::waypointScale() const
 
 qreal PathView::mapScale(int zoom) const
 {
-	return ((360.0/(qreal)(1<<zoom))/(qreal)TILE_SIZE);
+	return ((360.0/(qreal)(1<<zoom))/(qreal)Tile::size());
 }
 
 void PathView::updatePOIVisibility()
@@ -422,7 +458,8 @@ void PathView::zoom(int z, const QPointF &pos)
 	rescale(mapScale(_zoom));
 	QRectF br = trackBoundingRect() | routeBoundingRect()
 	  | waypointBoundingRect();
-	QRectF ba = br.adjusted(-TILE_SIZE, -TILE_SIZE, TILE_SIZE, TILE_SIZE);
+	QRectF ba = br.adjusted(-Tile::size(), -Tile::size(), Tile::size(),
+	  Tile::size());
 	_scene->setSceneRect(ba);
 
 	if (br.width() < viewport()->size().width()
@@ -603,8 +640,8 @@ void PathView::drawBackground(QPainter *painter, const QRectF &rect)
 	  -tm.y() / _scale))).toPoint();
 
 	QList<Tile> tiles;
-	for (int i = 0; i <= rr.size().width() / TILE_SIZE + 1; i++) {
-		for (int j = 0; j <= rr.size().height() / TILE_SIZE + 1; j++) {
+	for (int i = 0; i <= rr.size().width() / Tile::size() + 1; i++) {
+		for (int j = 0; j <= rr.size().height() / Tile::size() + 1; j++) {
 			tiles.append(Tile(QPoint(tile.x() + i, tile.y() + j), _zoom));
 		}
 	}
@@ -613,8 +650,8 @@ void PathView::drawBackground(QPainter *painter, const QRectF &rect)
 
 	for (int i = 0; i < tiles.count(); i++) {
 		Tile &t = tiles[i];
-		QPoint tp(tl.x() + (t.xy().x() - tile.x()) * TILE_SIZE,
-		  tl.y() + (t.xy().y() - tile.y()) * TILE_SIZE);
+		QPoint tp(tl.x() + (t.xy().x() - tile.x()) * Tile::size(),
+		  tl.y() + (t.xy().y() - tile.y()) * Tile::size());
 		painter->drawPixmap(tp, t.pixmap());
 	}
 }
@@ -628,7 +665,8 @@ void PathView::resizeEvent(QResizeEvent *e)
 
 	QRectF br = trackBoundingRect() | routeBoundingRect()
 	  | waypointBoundingRect();
-	QRectF ba = br.adjusted(-TILE_SIZE, -TILE_SIZE, TILE_SIZE, TILE_SIZE);
+	QRectF ba = br.adjusted(-Tile::size(), -Tile::size(), Tile::size(),
+	  Tile::size());
 
 	if (ba.width() < e->size().width()) {
 		qreal diff = e->size().width() - ba.width();
diff --git a/src/poi.cpp b/src/poi.cpp
index 3665c514..603ef56d 100644
--- a/src/poi.cpp
+++ b/src/poi.cpp
@@ -3,7 +3,6 @@
 #include <QList>
 #include "pathitem.h"
 #include "waypointitem.h"
-#include "ll.h"
 #include "data.h"
 #include "poi.h"
 
@@ -36,10 +35,10 @@ bool POI::loadFile(const QString &fileName)
 	index.end = _data.size() - 1;
 
 	for (int i = index.start; i <= index.end; i++) {
-		const QPointF &p = _data.at(i).coordinates();
+		const Coordinates &p = _data.at(i).coordinates();
 		qreal c[2];
-		c[0] = p.x();
-		c[1] = p.y();
+		c[0] = p.lon();
+		c[1] = p.lat();
 		_tree.Insert(c, c, i);
 	}
 
@@ -67,11 +66,11 @@ QVector<Waypoint> POI::points(const PathItem *path) const
 	const QPainterPath &pp = path->path();
 
 	for (int i = 0; i < pp.elementCount(); i++) {
-		QPointF p = mercator2ll(pp.elementAt(i));
-		min[0] = p.x() - _radius;
-		min[1] = -p.y() - _radius;
-		max[0] = p.x() + _radius;
-		max[1] = -p.y() + _radius;
+		Coordinates p = Coordinates::fromMercator(pp.elementAt(i));
+		min[0] = p.lon() - _radius;
+		min[1] = -p.lat() - _radius;
+		max[0] = p.lon() + _radius;
+		max[1] = -p.lat() + _radius;
 		_tree.Search(min, max, cb, &set);
 	}
 
@@ -92,11 +91,11 @@ QVector<Waypoint> POI::points(const QList<WaypointItem*> &list)
 	qreal min[2], max[2];
 
 	for (int i = 0; i < list.count(); i++) {
-		const QPointF &p = list.at(i)->waypoint().coordinates();
-		min[0] = p.x() - _radius;
-		min[1] = p.y() - _radius;
-		max[0] = p.x() + _radius;
-		max[1] = p.y() + _radius;
+		const Coordinates &p = list.at(i)->waypoint().coordinates();
+		min[0] = p.lon() - _radius;
+		min[1] = p.lat() - _radius;
+		max[0] = p.lon() + _radius;
+		max[1] = p.lat() + _radius;
 		_tree.Search(min, max, cb, &set);
 	}
 
@@ -116,11 +115,11 @@ QVector<Waypoint> POI::points(const QList<Waypoint> &list) const
 	qreal min[2], max[2];
 
 	for (int i = 0; i < list.count(); i++) {
-		const QPointF &p = list.at(i).coordinates();
-		min[0] = p.x() - _radius;
-		min[1] = p.y() - _radius;
-		max[0] = p.x() + _radius;
-		max[1] = p.y() + _radius;
+		const Coordinates &p = list.at(i).coordinates();
+		min[0] = p.lon() - _radius;
+		min[1] = p.lat() - _radius;
+		max[0] = p.lon() + _radius;
+		max[1] = p.lat() + _radius;
 		_tree.Search(min, max, cb, &set);
 	}
 
@@ -148,10 +147,10 @@ void POI::enableFile(const QString &fileName, bool enable)
 			continue;
 
 		for (int j = idx.start; j <= idx.end; j++) {
-			const QPointF &p = _data.at(j).coordinates();
+			const Coordinates &p = _data.at(j).coordinates();
 			qreal c[2];
-			c[0] = p.x();
-			c[1] = p.y();
+			c[0] = p.lon();
+			c[1] = p.lat();
 			_tree.Insert(c, c, j);
 		}
 	}
diff --git a/src/rd.h b/src/rd.h
new file mode 100644
index 00000000..fc746d46
--- /dev/null
+++ b/src/rd.h
@@ -0,0 +1,13 @@
+#ifndef RD_H
+#define RD_H
+
+#include <cmath>
+
+#ifndef M_PI
+	#define M_PI 3.14159265358979323846
+#endif // M_PI
+
+#define deg2rad(d) (((d)*M_PI)/180.0)
+#define rad2deg(d) (((d)*180.0)/M_PI)
+
+#endif // RD_H
diff --git a/src/route.cpp b/src/route.cpp
index f145e21d..f2b0c4fc 100644
--- a/src/route.cpp
+++ b/src/route.cpp
@@ -1,4 +1,3 @@
-#include "ll.h"
 #include "route.h"
 
 Route::Route(const QVector<Waypoint> &data) : _data(data)
@@ -7,7 +6,7 @@ Route::Route(const QVector<Waypoint> &data) : _data(data)
 
 	_distance.append(dist);
 	for (int i = 1; i < data.count(); i++) {
-		dist += llDistance(data.at(i).coordinates(), data.at(i-1).coordinates());
+		dist += data.at(i).coordinates().distanceTo(data.at(i-1).coordinates());
 		_distance.append(dist);
 	}
 }
diff --git a/src/routeitem.cpp b/src/routeitem.cpp
index 7cea8dae..1a07e4e1 100644
--- a/src/routeitem.cpp
+++ b/src/routeitem.cpp
@@ -1,6 +1,5 @@
 #include <QApplication>
 #include <QPainter>
-#include "ll.h"
 #include "misc.h"
 #include "waypoint.h"
 #include "waypointitem.h"
@@ -23,13 +22,14 @@ RouteItem::RouteItem(const Route &route, QGraphicsItem *parent)
 {
 	QVector<Waypoint> r = route.route();
 	Q_ASSERT(r.count() >= 2);
+	QPointF p;
 
 	new WaypointItem(r.at(0), this);
-	const QPointF &p = r.at(0).coordinates();
-	_path.moveTo(ll2mercator(QPointF(p.x(), -p.y())));
+	p = r.at(0).coordinates().toMercator();
+	_path.moveTo(QPointF(p.x(), -p.y()));
 	for (int i = 1; i < r.size(); i++) {
-		const QPointF &p = r.at(i).coordinates();
-		_path.lineTo(ll2mercator(QPointF(p.x(), -p.y())));
+		p = r.at(i).coordinates().toMercator();
+		_path.lineTo(QPointF(p.x(), -p.y()));
 		new WaypointItem(r.at(i), this);
 	}
 
diff --git a/src/scaleitem.cpp b/src/scaleitem.cpp
index c93e9982..46dde63e 100644
--- a/src/scaleitem.cpp
+++ b/src/scaleitem.cpp
@@ -1,22 +1,28 @@
 #include <QPainter>
 #include "config.h"
-#include "ll.h"
+#include "rd.h"
+#include "wgs84.h"
+#include "tile.h"
 #include "misc.h"
 #include "scaleitem.h"
 
 
 #define BORDER_WIDTH   1
-#define SCALE_WIDTH  132
-#define SCALE_HEIGHT 5
-#define SEGMENTS 3
-
-#define PADDING 4
+#define SCALE_WIDTH    132
+#define SCALE_HEIGHT   5
+#define SEGMENTS       3
+#define PADDING        4
 
+static qreal zoom2resolution(int zoom, qreal y)
+{
+	return (WGS84_RADIUS * 2 * M_PI / Tile::size()
+	  * cos(2 * atan(exp(deg2rad(y))) - M_PI/2)) / pow(2.0, zoom);
+}
 
 ScaleItem::ScaleItem(QGraphicsItem *parent) : QGraphicsItem(parent)
 {
 	_units = Metric;
-	_zoom = ZOOM_MIN;
+	_zoom = 0;
 	_lat = 0;
 
 #ifndef Q_OS_MAC
diff --git a/src/tcxparser.cpp b/src/tcxparser.cpp
index 0a13c273..96ab1f8b 100644
--- a/src/tcxparser.cpp
+++ b/src/tcxparser.cpp
@@ -1,16 +1,26 @@
 #include "tcxparser.h"
 
 
-QPointF TCXParser::position()
+Coordinates TCXParser::position()
 {
-	QPointF pos;
+	Coordinates pos;
+	qreal val;
+	bool res;
 
 	while (_reader.readNextStartElement()) {
-		if (_reader.name() == "LatitudeDegrees")
-			pos.setY(_reader.readElementText().toDouble());
-		else if (_reader.name() == "LongitudeDegrees")
-			pos.setX(_reader.readElementText().toDouble());
-		else
+		if (_reader.name() == "LatitudeDegrees") {
+			val = _reader.readElementText().toDouble(&res);
+			if (!res || (val < -90.0 || val > 90.0))
+				_reader.raiseError("Invalid latitude.");
+			else
+				pos.setLat(_reader.readElementText().toDouble(&res));
+		} else if (_reader.name() == "LongitudeDegrees") {
+			val = _reader.readElementText().toDouble(&res);
+			if (!res || (val < -180.0 || val > 180.0))
+				_reader.raiseError("Invalid longitude.");
+			else
+				pos.setLon(_reader.readElementText().toDouble(&res));
+		} else
 			_reader.skipCurrentElement();
 	}
 
diff --git a/src/tcxparser.h b/src/tcxparser.h
index 3dc0f846..7ea54a3d 100644
--- a/src/tcxparser.h
+++ b/src/tcxparser.h
@@ -32,7 +32,7 @@ private:
 	void trackpointData();
 	void routepointData();
 	void waypointData();
-	QPointF position();
+	Coordinates position();
 
 	QXmlStreamReader _reader;
 	QVector<Trackpoint> *_track;
diff --git a/src/tile.h b/src/tile.h
new file mode 100644
index 00000000..3cf5082c
--- /dev/null
+++ b/src/tile.h
@@ -0,0 +1,25 @@
+#ifndef TILE_H
+#define TILE_H
+
+#include <QPixmap>
+#include <QPoint>
+
+class Tile
+{
+public:
+	Tile(const QPoint &xy, int zoom)
+		{_xy = xy; _zoom = zoom;}
+
+	int zoom() const {return _zoom;}
+	const QPoint& xy() const {return _xy;}
+	QPixmap& pixmap() {return _pixmap;}
+
+	static int size() {return 256;}
+
+private:
+	int _zoom;
+	QPoint _xy;
+	QPixmap _pixmap;
+};
+
+#endif // TILE_H
diff --git a/src/track.cpp b/src/track.cpp
index ff58c41c..a48b2c7a 100644
--- a/src/track.cpp
+++ b/src/track.cpp
@@ -1,4 +1,3 @@
-#include "ll.h"
 #include "track.h"
 
 
@@ -87,7 +86,7 @@ Track::Track(const QVector<Trackpoint> &data) : _data(data)
 	_distance.append(0);
 	_time.append(0);
 	for (int i = 1; i < data.count(); i++) {
-		dist += llDistance(data.at(i).coordinates(), data.at(i-1).coordinates());
+		dist += data.at(i).coordinates().distanceTo(data.at(i-1).coordinates());
 		_distance.append(dist);
 
 		if (data.first().hasTimestamp() && data.at(i).hasTimestamp())
diff --git a/src/trackitem.cpp b/src/trackitem.cpp
index cc065f4d..831ee124 100644
--- a/src/trackitem.cpp
+++ b/src/trackitem.cpp
@@ -1,7 +1,6 @@
 #include <QApplication>
 #include <QCursor>
 #include <QPainter>
-#include "ll.h"
 #include "misc.h"
 #include "tooltip.h"
 #include "trackitem.h"
@@ -25,14 +24,15 @@ QString TrackItem::toolTip()
 TrackItem::TrackItem(const Track &track, QGraphicsItem *parent)
   : PathItem(parent)
 {
+	QPointF p;
 	const QVector<Trackpoint> &t = track.track();
 	Q_ASSERT(t.count() >= 2);
 
-	const QPointF &p = t.at(0).coordinates();
-	_path.moveTo(ll2mercator(QPointF(p.x(), -p.y())));
+	p = t.first().coordinates().toMercator();
+	_path.moveTo(QPointF(p.x(), -p.y()));
 	for (int i = 1; i < t.size(); i++) {
-		const QPointF &p = t.at(i).coordinates();
-		_path.lineTo(ll2mercator(QPointF(p.x(), -p.y())));
+		p = t.at(i).coordinates().toMercator();
+		_path.lineTo(QPointF(p.x(), -p.y()));
 	}
 
 	updateShape();
diff --git a/src/trackpoint.h b/src/trackpoint.h
index 909bb5de..f65a0fa8 100644
--- a/src/trackpoint.h
+++ b/src/trackpoint.h
@@ -1,10 +1,10 @@
 #ifndef TRACKPOINT_H
 #define TRACKPOINT_H
 
-#include <QPointF>
 #include <QDateTime>
 #include <QDebug>
 #include <cmath>
+#include "coordinates.h"
 
 class Trackpoint
 {
@@ -13,9 +13,9 @@ public:
 		_elevation = NAN; _geoidHeight = 0; _speed = NAN; _heartRate = NAN;
 		_temperature = NAN;
 	}
-	Trackpoint(const QPointF &coordinates) {_coordinates = coordinates;}
+	Trackpoint(const Coordinates &coordinates) {_coordinates = coordinates;}
 
-	const QPointF &coordinates() const {return _coordinates;}
+	const Coordinates &coordinates() const {return _coordinates;}
 	const QDateTime &timestamp() const {return _timestamp;}
 	qreal elevation() const {return _elevation;}
 	qreal geoidHeight() const {return _geoidHeight;}
@@ -23,7 +23,7 @@ public:
 	qreal heartRate() const {return _heartRate;}
 	qreal temperature() const {return _temperature;}
 
-	void setCoordinates(const QPointF &coordinates)
+	void setCoordinates(const Coordinates &coordinates)
 	  {_coordinates = coordinates;}
 	void setTimestamp(const QDateTime &timestamp) {_timestamp = timestamp;}
 	void setElevation(qreal elevation) {_elevation = elevation;}
@@ -39,7 +39,7 @@ public:
 	bool hasTemperature() const {return !std::isnan(_temperature);}
 
 private:
-	QPointF _coordinates;
+	Coordinates _coordinates;
 	QDateTime _timestamp;
 	qreal _elevation;
 	qreal _geoidHeight;
diff --git a/src/waypoint.h b/src/waypoint.h
index 561ed0eb..0d373ab7 100644
--- a/src/waypoint.h
+++ b/src/waypoint.h
@@ -1,28 +1,28 @@
 #ifndef WAYPOINT_H
 #define WAYPOINT_H
 
-#include <QPointF>
 #include <QString>
 #include <QDateTime>
 #include <QHash>
 #include <QDebug>
 #include <cmath>
+#include "coordinates.h"
 
 class Waypoint
 {
 public:
 	Waypoint() {_elevation = NAN; _geoidHeight = 0;}
-	Waypoint(const QPointF &coordinates)
+	Waypoint(const Coordinates &coordinates)
 	  : _coordinates(coordinates) {_elevation = NAN; _geoidHeight = 0;}
 
-	const QPointF &coordinates() const {return _coordinates;}
+	const Coordinates &coordinates() const {return _coordinates;}
 	const QString &name() const {return _name;}
 	const QString &description() const {return _description;}
 	const QDateTime &timestamp() const {return _timestamp;}
 	qreal elevation() const {return _elevation;}
 	qreal geoidHeight() const {return _geoidHeight;}
 
-	void setCoordinates(const QPointF &coordinates)
+	void setCoordinates(const Coordinates &coordinates)
 	  {_coordinates = coordinates;}
 	void setName(const QString &name) {_name = name;}
 	void setDescription(const QString &description)
@@ -38,7 +38,7 @@ public:
 	  && this->_coordinates == other._coordinates;}
 
 private:
-	QPointF _coordinates;
+	Coordinates _coordinates;
 	QString _name;
 	QString _description;
 	QDateTime _timestamp;
diff --git a/src/waypointitem.cpp b/src/waypointitem.cpp
index 065a3dbd..5a6b4dce 100644
--- a/src/waypointitem.cpp
+++ b/src/waypointitem.cpp
@@ -1,7 +1,6 @@
 #include <QApplication>
 #include <QPainter>
 #include "config.h"
-#include "ll.h"
 #include "misc.h"
 #include "tooltip.h"
 #include "waypointitem.h"
@@ -39,8 +38,8 @@ WaypointItem::WaypointItem(const Waypoint &waypoint, QGraphicsItem *parent)
 	_hover = false;
 
 	_waypoint = waypoint;
-	_coordinates = ll2mercator(QPointF(waypoint.coordinates().x(),
-	  -waypoint.coordinates().y()));
+	QPointF p = waypoint.coordinates().toMercator();
+	_coordinates = QPointF(p.x(), -p.y());
 
 	updateShape();
 
diff --git a/src/wgs84.h b/src/wgs84.h
new file mode 100644
index 00000000..766f3440
--- /dev/null
+++ b/src/wgs84.h
@@ -0,0 +1,6 @@
+#ifndef WGS84_H
+#define WGS84_H
+
+#define WGS84_RADIUS 6378137.0
+
+#endif // WGS84_H