diff --git a/src/plot.cpp b/src/plot.cpp
--- a/src/plot.cpp
+++ b/src/plot.cpp
@@ -20,12 +20,16 @@
 #include <QRectF>
 #include <QKeySequence>
 #include <QColor>
-
+#include <qwt_symbol.h>
+#include <qwt_plot_curve.h>
 #include <math.h>
 
 #include "plot.h"
 #include "utils.h"
 
+static const int SYMBOL_SIZE = 5;
+static const int SYMBOL_SHOW_AT_WIDTH = 15;
+
 Plot::Plot(QWidget* parent) :
     QwtPlot(parent),
     zoomer(this->canvas(), false),
@@ -37,6 +41,7 @@ Plot::Plot(QWidget* parent) :
     showLegendAction("Legend", this)
 {
     isAutoScaled = true;
+    isSymbolsOn = true;
 
     QObject::connect(&zoomer, &Zoomer::unzoomed, this, &Plot::unzoomed);
 
@@ -80,6 +85,18 @@ Plot::Plot(QWidget* parent) :
     connect(&showLegendAction, SELECT<bool>::OVERLOAD_OF(&QAction::triggered),
             [this](bool enabled){legend.setVisible(enabled); replot();});
 
+    connect(&zoomer, &QwtPlotZoomer::zoomed,
+            [this](const QRectF &rect)
+            {
+                onXScaleChanged();
+            });
+
+    connect(this, &QwtPlot::itemAttached,
+            [this](QwtPlotItem *plotItem, bool on)
+            {
+                if (isSymbolsOn) updateSymbols();
+            });
+
     snapshotOverlay = NULL;
 }
 
@@ -230,3 +247,45 @@ void Plot::flashSnapshotOverlay()
                 snapshotOverlay = NULL;
             });
 }
+
+void Plot::onXScaleChanged()
+{
+    auto sw = axisWidget(QwtPlot::xBottom);
+    auto paintDist = sw->scaleDraw()->scaleMap().pDist();
+    auto scaleDist = sw->scaleDraw()->scaleMap().sDist();
+    double symDisPx = paintDist / scaleDist;
+
+    if (symDisPx > SYMBOL_SHOW_AT_WIDTH)
+    {
+        isSymbolsOn = true;
+    }
+    else
+    {
+        isSymbolsOn = false;
+    }
+
+    updateSymbols();
+}
+
+void Plot::updateSymbols()
+{
+    const QwtPlotItemList curves = itemList( QwtPlotItem::Rtti_PlotCurve );
+
+    if (curves.size() > 0)
+    {
+        for (unsigned i = 0; i < curves.size(); i++)
+        {
+            QwtSymbol* symbol = NULL;
+            QwtPlotCurve* curve = static_cast<QwtPlotCurve*>(curves[i]);
+            qDebug() << i;
+            if (isSymbolsOn)
+            {
+                symbol = new QwtSymbol(QwtSymbol::Ellipse,
+                                       QBrush(Qt::white),
+                                       curve->pen(),
+                                       QSize(SYMBOL_SIZE, SYMBOL_SIZE));
+            }
+            curve->setSymbol(symbol);
+        }
+    }
+}
diff --git a/src/plot.h b/src/plot.h
--- a/src/plot.h
+++ b/src/plot.h
@@ -47,6 +47,7 @@ public:
 private:
     bool isAutoScaled;
     double yMin, yMax;
+    bool isSymbolsOn;
     Zoomer zoomer;
     ScaleZoomer sZoomer;
     QwtPlotGrid grid;
@@ -59,6 +60,8 @@ private:
     QAction darkBackgroundAction;
     QAction showLegendAction;
 
+    /// update the display of symbols depending on `isSymbolsOn`
+    void updateSymbols();
     void resetAxes();
 
 public slots:
@@ -72,6 +75,7 @@ public slots:
 
 private slots:
     void unzoomed();
+    void onXScaleChanged();
 };
 
 #endif // PLOT_H