diff --git a/src/elevationgraph.cpp b/src/elevationgraph.cpp
index ee5dc04a..34a69d0b 100644
--- a/src/elevationgraph.cpp
+++ b/src/elevationgraph.cpp
@@ -16,6 +16,7 @@ ElevationGraph::ElevationGraph(QWidget *parent) : GraphView(parent)
 	GraphView::setXUnits(tr("km"));
 	GraphView::setYUnits(tr("m"));
 	GraphView::setXScale(M2KM);
+	GraphView::setMinRange(50.0);
 }
 
 void ElevationGraph::addInfo()
diff --git a/src/graphview.cpp b/src/graphview.cpp
index e84766e6..fe2826ea 100644
--- a/src/graphview.cpp
+++ b/src/graphview.cpp
@@ -53,6 +53,7 @@ GraphView::GraphView(QWidget *parent)
 	_yScale = 1;
 
 	_precision = 0;
+	_minRange = 0.01;
 }
 
 GraphView::~GraphView()
@@ -166,8 +167,9 @@ void GraphView::resize(const QSizeF &size)
 {
 	QRectF r;
 	QSizeF mx, my;
+	QPointF rx, ry;
 	QTransform transform;
-	qreal xs, ys;
+	qreal xs, ys, diff;
 
 
 	if (_xAxis->scene() == _scene)
@@ -182,11 +184,21 @@ void GraphView::resize(const QSizeF &size)
 	for (int i = 0; i < _graphs.size(); i++)
 		_graphs.at(i)->resetTransform();
 
-	_xAxis->setRange(QPointF(_xMin * _xScale, _xMax * _xScale));
-	_yAxis->setRange(QPointF(_yMin * _yScale, _yMax * _yScale));
+	rx = QPointF(_xMin * _xScale, _xMax * _xScale);
+	ry = QPointF(_yMin * _yScale, _yMax * _yScale);
+	if ((diff = ry.y() - ry.x()) < _minRange)
+		ry = QPointF(ry.x() - (_minRange/2 - diff/2),
+		  ry.y() + (_minRange/2 - diff/2));
+	_xAxis->setRange(rx);
+	_yAxis->setRange(ry);
 	mx = _xAxis->margin();
 	my = _yAxis->margin();
+
 	r = _scene->itemsBoundingRect();
+	if (r.height() < _minRange)
+		r.adjust(0, -(_minRange/2 - r.height()/2), 0,
+		  _minRange/2 - r.height()/2);
+
 	xs = (size.width() - (my.width() + mx.width())) / r.width();
 	ys = (size.height() - (mx.height() + my.height())
 	  - _info->boundingRect().height()) / r.height();
@@ -196,6 +208,10 @@ void GraphView::resize(const QSizeF &size)
 		_graphs.at(i)->setTransform(transform);
 
 	r = _scene->itemsBoundingRect();
+	if (r.height() < _minRange * ys)
+		r.adjust(0, -(_minRange/2 * ys - r.height()/2), 0,
+		  (_minRange/2) * ys - r.height()/2);
+
 	_xAxis->setSize(r.width());
 	_yAxis->setSize(r.height());
 	_xAxis->setPos(r.bottomLeft());
@@ -280,9 +296,12 @@ void GraphView::emitSliderPositionChanged(const QPointF &pos)
 	emit sliderPositionChanged(val);
 
 	const QPainterPath &path = _graphs.at(0)->path();
+	QRectF br = path.boundingRect();
+	if (br.height() < _minRange)
+		br.adjust(0, -(_minRange/2 - br.height()/2), 0,
+		  _minRange/2 - br.height()/2);
 	QPointF p = path.pointAtPercent(val);
-	qreal r = (p.y() - path.boundingRect().bottom())
-	  / path.boundingRect().height();
+	qreal r = (p.y() - br.bottom()) / br.height();
 	_sliderInfo->setPos(QPointF(0, _slider->boundingRect().height() * r));
 	_sliderInfo->setText(QString::number(-p.y() * _yScale, 'f', _precision));
 }
diff --git a/src/graphview.h b/src/graphview.h
index aff2be98..8373b7da 100644
--- a/src/graphview.h
+++ b/src/graphview.h
@@ -41,7 +41,8 @@ public:
 	void setYUnits(const QString &units);
 	void setXScale(qreal scale);
 	void setYScale(qreal scale);
-	void setPrecision(int p) {_precision = p;}
+	void setPrecision(int precision) {_precision = precision;}
+	void setMinRange(qreal range) {_minRange = range;}
 
 	void redraw();
 
@@ -64,6 +65,7 @@ protected:
 	QString _xUnits, _yUnits;
 	QString _xLabel, _yLabel;
 	int _precision;
+	qreal _minRange;
 
 private slots:
 	void emitSliderPositionChanged(const QPointF &pos);
diff --git a/src/sliderinfoitem.cpp b/src/sliderinfoitem.cpp
index 4adbbea0..9bd0059b 100644
--- a/src/sliderinfoitem.cpp
+++ b/src/sliderinfoitem.cpp
@@ -7,7 +7,6 @@
 
 SliderInfoItem::SliderInfoItem(QGraphicsItem *parent) : QGraphicsItem(parent)
 {
-
 }
 
 void SliderInfoItem::updateBoundingRect()
diff --git a/src/track.cpp b/src/track.cpp
index f09215a3..806cea01 100644
--- a/src/track.cpp
+++ b/src/track.cpp
@@ -1,6 +1,8 @@
+#include <cmath>
 #include "ll.h"
 #include "track.h"
 
+
 #define WINDOW_EF 3
 #define WINDOW_SE 11
 #define WINDOW_SF 11
@@ -84,9 +86,13 @@ void Track::elevationGraph(QVector<QPointF> &graph) const
 	if (!_data.size())
 		return;
 
+	if (isnan(_data.at(0).elevation))
+		return;
 	raw.append(QPointF(0, _data.at(0).elevation));
 	for (int i = 1; i < _data.size(); i++) {
 		dist += llDistance(_data.at(i).coordinates, _data.at(i-1).coordinates);
+		if (isnan(_data.at(i).elevation))
+			return;
 		raw.append(QPointF(dist,  _data.at(i).elevation
 		  - _data.at(i).geoidheight));
 	}
@@ -108,7 +114,7 @@ void Track::speedGraph(QVector<QPointF> &graph) const
 		dt = _data.at(i-1).timestamp.msecsTo(_data.at(i).timestamp) / 1000.0;
 		dist += ds;
 
-		if (_data.at(i).speed < 0) {
+		if (isnan(_data.at(i).speed)) {
 			if (dt == 0)
 				continue;
 			v = ds / dt;
diff --git a/src/trackpoint.h b/src/trackpoint.h
index 0e181e93..773e3e21 100644
--- a/src/trackpoint.h
+++ b/src/trackpoint.h
@@ -3,6 +3,7 @@
 
 #include <QPointF>
 #include <QDateTime>
+#include <cmath>
 
 struct Trackpoint
 {
@@ -12,7 +13,7 @@ struct Trackpoint
 	qreal geoidheight;
 	qreal speed;
 
-	Trackpoint() {elevation = 0; geoidheight = 0; speed = -1;}
+	Trackpoint() {elevation = NAN; geoidheight = 0; speed = NAN;}
 };
 
 #endif // TRACKPOINT_H