diff --git a/Software/PC_Application/Traces/Marker/marker.cpp b/Software/PC_Application/Traces/Marker/marker.cpp
index 122c13b..ecaec13 100644
--- a/Software/PC_Application/Traces/Marker/marker.cpp
+++ b/Software/PC_Application/Traces/Marker/marker.cpp
@@ -85,8 +85,8 @@ void Marker::assignTrace(Trace *t)
         // Marker was just created and this is the first assignment to a trace.
         // Use display format on graph from preferences
         auto p = Preferences::getInstance();
-        if(p.Graphs.markerBehavior.showDataOnGraphs) {
-            if(p.Graphs.markerBehavior.showAllData) {
+        if(p.Marker.defaultBehavior.showDataOnGraphs) {
+            if(p.Marker.defaultBehavior.showAllData) {
                 for(auto f : applicableFormats()) {
                     formatGraph.insert(f);
                 }
@@ -598,7 +598,7 @@ void Marker::traceDataChanged()
             newdata = numeric_limits<complex<double>>::quiet_NaN();
         } else {
             // some data of the parent trace changed, check if marker data also changed
-            newdata = parentTrace->sample(parentTrace->index(position)).y;
+            newdata = parentTrace->interpolatedSample(position).y;
         }
     }
     if (newdata != data) {
@@ -839,8 +839,10 @@ void Marker::constrainPosition()
             } else if(position < parentTrace->minX()) {
                 position = parentTrace->minX();
             }
-            // set position to closest trace index
-            position = parentTrace->sample(parentTrace->index(position)).x;
+            if(!Preferences::getInstance().Marker.interpolatePoints) {
+                // marker interpolation disabled, set position to closest trace index
+                position = parentTrace->sample(parentTrace->index(position)).x;
+            }
         }
         traceDataChanged();
     }
diff --git a/Software/PC_Application/Traces/tracesmithchart.cpp b/Software/PC_Application/Traces/tracesmithchart.cpp
index 7a3117c..c16b989 100644
--- a/Software/PC_Application/Traces/tracesmithchart.cpp
+++ b/Software/PC_Application/Traces/tracesmithchart.cpp
@@ -5,6 +5,7 @@
 #include "ui_smithchartdialog.h"
 #include "unit.h"
 #include "QFileDialog"
+#include "Util/util.h"
 
 #include <QPainter>
 #include <array>
@@ -141,6 +142,7 @@ double TraceSmithChart::nearestTracePoint(Trace *t, QPoint pixel, double *distan
 {
     double closestDistance = numeric_limits<double>::max();
     double closestXpos = 0;
+    unsigned int closestIndex = 0;
     auto samples = t->size();
     for(unsigned int i=0;i<samples;i++) {
         auto data = t->sample(i);
@@ -154,6 +156,28 @@ double TraceSmithChart::nearestTracePoint(Trace *t, QPoint pixel, double *distan
         if(distance < closestDistance) {
             closestDistance = distance;
             closestXpos = t->sample(i).x;
+            closestIndex = i;
+        }
+    }
+    closestDistance = sqrt(closestDistance);
+    if(closestIndex > 0) {
+        auto l1 = dataToPixel(t->sample(closestIndex-1));
+        auto l2 = dataToPixel(t->sample(closestIndex));
+        double ratio;
+        auto distance = Util::distanceToLine(pixel, l1, l2, nullptr, &ratio);
+        if(distance < closestDistance) {
+            closestDistance = distance;
+            closestXpos = t->sample(closestIndex-1).x + (t->sample(closestIndex).x - t->sample(closestIndex-1).x) * ratio;
+        }
+    }
+    if(closestIndex < t->size() - 1) {
+        auto l1 = dataToPixel(t->sample(closestIndex));
+        auto l2 = dataToPixel(t->sample(closestIndex+1));
+        double ratio;
+        auto distance = Util::distanceToLine(pixel, l1, l2, nullptr, &ratio);
+        if(distance < closestDistance) {
+            closestDistance = distance;
+            closestXpos = t->sample(closestIndex).x + (t->sample(closestIndex+1).x - t->sample(closestIndex).x) * ratio;
         }
     }
     if(distance) {
diff --git a/Software/PC_Application/Traces/tracexyplot.cpp b/Software/PC_Application/Traces/tracexyplot.cpp
index 7d75e06..84f6e3d 100644
--- a/Software/PC_Application/Traces/tracexyplot.cpp
+++ b/Software/PC_Application/Traces/tracexyplot.cpp
@@ -491,7 +491,17 @@ void TraceXYPlot::draw(QPainter &p)
                         continue;
                     }
                     auto t = m->getTrace();
-                    QPointF markerPoint = traceToCoordinate(t, t->index(xPosition), YAxis[i].type);
+                    auto index = t->index(xPosition);
+                    QPointF markerPoint;
+                    if(xPosition < t->sample(index).x && index > 0) {
+                        // marker is not located exactly at this point, interpolate display location
+                        QPointF l0 = traceToCoordinate(t, index - 1, YAxis[i].type);
+                        QPointF l1 = traceToCoordinate(t, index, YAxis[i].type);
+                        auto t0 = (xPosition - t->sample(index - 1).x) / (t->sample(index).x - t->sample(index - 1).x);
+                        markerPoint = l0 + (l1 - l0) * t0;
+                    } else {
+                        markerPoint = traceToCoordinate(t, t->index(xPosition), YAxis[i].type);
+                    }
                     auto point = plotValueToPixel(markerPoint, i);
                     if(!plotRect.contains(point)) {
                         // out of screen
@@ -1096,6 +1106,7 @@ double TraceXYPlot::nearestTracePoint(Trace *t, QPoint pixel, double *distance)
     }
     double closestDistance = numeric_limits<double>::max();
     double closestXpos = 0;
+    unsigned int closestIndex = 0;
     auto samples = t->size();
     for(unsigned int i=0;i<samples;i++) {
         auto point = traceToCoordinate(t, i, YAxis[0].type);
@@ -1108,6 +1119,28 @@ double TraceXYPlot::nearestTracePoint(Trace *t, QPoint pixel, double *distance)
         if(distance < closestDistance) {
             closestDistance = distance;
             closestXpos = point.x();
+            closestIndex = i;
+        }
+    }
+    closestDistance = sqrt(closestDistance);
+    if(closestIndex > 0) {
+        auto l1 = plotValueToPixel(traceToCoordinate(t, closestIndex - 1, YAxis[0].type), 0);
+        auto l2 = plotValueToPixel(traceToCoordinate(t, closestIndex, YAxis[0].type), 0);
+        double ratio;
+        auto distance = Util::distanceToLine(pixel, l1, l2, nullptr, &ratio);
+        if(distance < closestDistance) {
+            closestDistance = distance;
+            closestXpos = t->sample(closestIndex-1).x + (t->sample(closestIndex).x - t->sample(closestIndex-1).x) * ratio;
+        }
+    }
+    if(closestIndex < t->size() - 1) {
+        auto l1 = plotValueToPixel(traceToCoordinate(t, closestIndex, YAxis[0].type), 0);
+        auto l2 = plotValueToPixel(traceToCoordinate(t, closestIndex + 1, YAxis[0].type), 0);
+        double ratio;
+        auto distance = Util::distanceToLine(pixel, l1, l2, nullptr, &ratio);
+        if(distance < closestDistance) {
+            closestDistance = distance;
+            closestXpos = t->sample(closestIndex).x + (t->sample(closestIndex+1).x - t->sample(closestIndex).x) * ratio;
         }
     }
     if(XAxis.type == XAxisType::Distance) {
diff --git a/Software/PC_Application/Util/util.cpp b/Software/PC_Application/Util/util.cpp
index 90baaef..fe2e2ab 100644
--- a/Software/PC_Application/Util/util.cpp
+++ b/Software/PC_Application/Util/util.cpp
@@ -1,5 +1,7 @@
 #include "util.h"
 
+#include <QVector2D>
+
 void Util::unwrapPhase(std::vector<double> &phase)
 {
     for (unsigned int i = 1; i < phase.size(); i++) {
@@ -24,3 +26,31 @@ void Util::linearRegression(const std::vector<double> &input, double &B_0, doubl
     B_1 = ss_xy / ss_xx;
     B_0 = y_mean - B_1 * x_mean;
 }
+
+double Util::distanceToLine(QPointF point, QPointF l1, QPointF l2, QPointF *closestLinePoint, double *pointRatio)
+{
+    auto M = l2 - l1;
+    auto t0 = QPointF::dotProduct(M, point - l1) / QPointF::dotProduct(M, M);
+    QPointF closestPoint;
+    QVector2D orthVect;
+    if (t0 <= 0) {
+        orthVect = QVector2D(point - l1);
+        closestPoint = l1;
+        t0 = 0;
+    } else if(t0 >= 1) {
+        orthVect = QVector2D(point - l2);
+        closestPoint = l2;
+        t0 = 1;
+    } else {
+        auto intersect = l1 + t0 * M;
+        orthVect = QVector2D(point - intersect);
+        closestPoint = intersect;
+    }
+    if(closestLinePoint) {
+        *closestLinePoint = closestPoint;
+    }
+    if(pointRatio) {
+        *pointRatio = t0;
+    }
+    return orthVect.length();
+}
diff --git a/Software/PC_Application/Util/util.h b/Software/PC_Application/Util/util.h
index 806262e..30a61e6 100644
--- a/Software/PC_Application/Util/util.h
+++ b/Software/PC_Application/Util/util.h
@@ -7,6 +7,7 @@
 #include <vector>
 
 #include <QColor>
+#include <QPoint>
 
 namespace Util {
     template<typename T> T Scale(T value, T from_low, T from_high, T to_low, T to_high, bool log_from = false, bool log_to = false) {
@@ -69,6 +70,8 @@ namespace Util {
 
     // input values are Y coordinates, assumes evenly spaced linear X values from 0 to input.size() - 1
     void linearRegression(const std::vector<double> &input, double &B_0, double &B_1);
+
+    double distanceToLine(QPointF point, QPointF l1, QPointF l2, QPointF *closestLinePoint = nullptr, double *pointRatio = nullptr);
 }
 
 #endif // UTILH_H
diff --git a/Software/PC_Application/preferences.cpp b/Software/PC_Application/preferences.cpp
index 4a3e6a2..8b2dcb6 100644
--- a/Software/PC_Application/preferences.cpp
+++ b/Software/PC_Application/preferences.cpp
@@ -80,8 +80,8 @@ PreferencesDialog::PreferencesDialog(Preferences *pref, QWidget *parent) :
         ui->SCPIServerEnabled->setEnabled(false);
     }
 
-    connect(ui->GraphsShowMarkerData, &QCheckBox::toggled, [=](bool enabled) {
-         ui->GraphsShowAllMarkerData->setEnabled(enabled);
+    connect(ui->MarkerShowMarkerData, &QCheckBox::toggled, [=](bool enabled) {
+         ui->MarkerShowAllMarkerData->setEnabled(enabled);
     });
 
     // Page selection
@@ -128,6 +128,7 @@ PreferencesDialog::PreferencesDialog(Preferences *pref, QWidget *parent) :
         p->Startup.SA.window = ui->StartupSAWindow->currentIndex();
         p->Startup.SA.detector = ui->StartupSADetector->currentIndex();
         p->Startup.SA.signalID = ui->StartupSASignalID->isChecked();
+
         p->Acquisition.alwaysExciteBothPorts = ui->AcquisitionAlwaysExciteBoth->isChecked();
         p->Acquisition.suppressPeaks = ui->AcquisitionSuppressPeaks->isChecked();
         p->Acquisition.adjustPowerLevel = ui->AcquisitionAdjustPowerLevel->isChecked();
@@ -135,6 +136,7 @@ PreferencesDialog::PreferencesDialog(Preferences *pref, QWidget *parent) :
         p->Acquisition.useDFTinSAmode = ui->AcquisitionUseDFT->isChecked();
         p->Acquisition.RBWLimitForDFT = ui->AcquisitionDFTlimitRBW->value();
         p->Acquisition.useMedianAveraging = ui->AcquisitionAveragingMode->currentIndex() == 1;
+
         p->Graphs.showUnits = ui->GraphsShowUnit->isChecked();
         p->Graphs.Color.background = ui->GraphsColorBackground->getColor();
         p->Graphs.Color.axis = ui->GraphsColorAxis->getColor();
@@ -142,9 +144,12 @@ PreferencesDialog::PreferencesDialog(Preferences *pref, QWidget *parent) :
         p->Graphs.Color.Ticks.Background.background = ui->GraphsColorTicksBackground->getColor();
         p->Graphs.Color.Ticks.divisions = ui->GraphsColorTicksDivisions->getColor();
         p->Graphs.domainChangeBehavior = (GraphDomainChangeBehavior) ui->GraphsDomainChangeBehavior->currentIndex();
-        p->Graphs.markerBehavior.showDataOnGraphs = ui->GraphsShowMarkerData->isChecked();
-        p->Graphs.markerBehavior.showAllData = ui->GraphsShowAllMarkerData->isChecked();
         p->Graphs.lineWidth = ui->GraphsLineWidth->value();
+
+        p->Marker.defaultBehavior.showDataOnGraphs = ui->MarkerShowMarkerData->isChecked();
+        p->Marker.defaultBehavior.showAllData = ui->MarkerShowAllMarkerData->isChecked();
+        p->Marker.interpolatePoints = ui->MarkerInterpolate->currentIndex() == 1;
+
         p->SCPIServer.enabled = ui->SCPIServerEnabled->isChecked();
         p->SCPIServer.port = ui->SCPIServerPort->value();
         accept();
@@ -211,10 +216,12 @@ void PreferencesDialog::setInitialGUIState()
     ui->GraphsColorTicksBackgroundEnabled->setChecked(p->Graphs.Color.Ticks.Background.enabled);
     ui->GraphsColorTicksBackground->setColor(p->Graphs.Color.Ticks.Background.background);
     ui->GraphsDomainChangeBehavior->setCurrentIndex((int) p->Graphs.domainChangeBehavior);
-    ui->GraphsShowMarkerData->setChecked(p->Graphs.markerBehavior.showDataOnGraphs);
-    ui->GraphsShowAllMarkerData->setChecked(p->Graphs.markerBehavior.showAllData);
     ui->GraphsLineWidth->setValue(p->Graphs.lineWidth);
 
+    ui->MarkerShowMarkerData->setChecked(p->Marker.defaultBehavior.showDataOnGraphs);
+    ui->MarkerShowAllMarkerData->setChecked(p->Marker.defaultBehavior.showAllData);
+    ui->MarkerInterpolate->setCurrentIndex(p->Marker.interpolatePoints ? 1 : 0);
+
     ui->SCPIServerEnabled->setChecked(p->SCPIServer.enabled);
     ui->SCPIServerPort->setValue(p->SCPIServer.port);
 
diff --git a/Software/PC_Application/preferences.h b/Software/PC_Application/preferences.h
index d3f3c83..475a1a2 100644
--- a/Software/PC_Application/preferences.h
+++ b/Software/PC_Application/preferences.h
@@ -83,12 +83,16 @@ public:
             } Ticks;
         } Color;
         GraphDomainChangeBehavior domainChangeBehavior;
+
+        double lineWidth;
+    } Graphs;
+    struct {
         struct {
             bool showDataOnGraphs;
             bool showAllData;
-        } markerBehavior;
-        double lineWidth;
-    } Graphs;
+        } defaultBehavior;
+        bool interpolatePoints;
+    } Marker;
     struct {
         bool enabled;
         int port;
@@ -104,7 +108,7 @@ private:
         QString name;
         QVariant def;
     };
-    const std::array<SettingDescription, 41> descr = {{
+    const std::array<SettingDescription, 42> descr = {{
         {&Startup.ConnectToFirstDevice, "Startup.ConnectToFirstDevice", true},
         {&Startup.RememberSweepSettings, "Startup.RememberSweepSettings", false},
         {&Startup.DefaultSweep.type, "Startup.DefaultSweep.type", "Frequency"},
@@ -141,9 +145,10 @@ private:
         {&Graphs.Color.Ticks.Background.background, "Graphs.Color.Ticks.Background.background", QColor(20, 20, 20)},
         {&Graphs.Color.Ticks.divisions, "Graphs.Color.Ticks.divisions", QColor(Qt::gray)},
         {&Graphs.domainChangeBehavior, "Graphs.domainChangeBehavior", GraphDomainChangeBehavior::AdjustGraphs},
-        {&Graphs.markerBehavior.showDataOnGraphs, "Graphs.markerBehavior.ShowDataOnGraphs", true},
-        {&Graphs.markerBehavior.showAllData, "Graphs.markerBehavior.ShowAllData", false},
         {&Graphs.lineWidth, "Graphs.lineWidth", 1.0},
+        {&Marker.defaultBehavior.showDataOnGraphs, "Marker.defaultBehavior.ShowDataOnGraphs", true},
+        {&Marker.defaultBehavior.showAllData, "Marker.defaultBehavior.ShowAllData", false},
+        {&Marker.interpolatePoints, "Marker.interpolatePoints", false},
         {&SCPIServer.enabled, "SCPIServer.enabled", true},
         {&SCPIServer.port, "SCPIServer.port", 19542},
     }};
diff --git a/Software/PC_Application/preferencesdialog.ui b/Software/PC_Application/preferencesdialog.ui
index 9411c97..52a0b65 100644
--- a/Software/PC_Application/preferencesdialog.ui
+++ b/Software/PC_Application/preferencesdialog.ui
@@ -56,6 +56,11 @@
          <string>Graphs</string>
         </property>
        </item>
+       <item>
+        <property name="text">
+         <string>Marker</string>
+        </property>
+       </item>
        <item>
         <property name="text">
          <string>SCPI Server</string>
@@ -78,7 +83,7 @@
         </size>
        </property>
        <property name="currentIndex">
-        <number>2</number>
+        <number>3</number>
        </property>
        <widget class="QWidget" name="Startup">
         <layout class="QHBoxLayout" name="horizontalLayout_4">
@@ -831,29 +836,6 @@
              </layout>
             </widget>
            </item>
-           <item>
-            <widget class="QGroupBox" name="groupBox_9">
-             <property name="title">
-              <string>Marker Default Behavior</string>
-             </property>
-             <layout class="QVBoxLayout" name="verticalLayout_9">
-              <item>
-               <widget class="QCheckBox" name="GraphsShowMarkerData">
-                <property name="text">
-                 <string>Show data on graphs</string>
-                </property>
-               </widget>
-              </item>
-              <item>
-               <widget class="QCheckBox" name="GraphsShowAllMarkerData">
-                <property name="text">
-                 <string>Show data in all available formats</string>
-                </property>
-               </widget>
-              </item>
-             </layout>
-            </widget>
-           </item>
            <item>
             <spacer name="verticalSpacer_3">
              <property name="orientation">
@@ -884,6 +866,88 @@
          </item>
         </layout>
        </widget>
+       <widget class="QWidget" name="Marker">
+        <layout class="QHBoxLayout" name="horizontalLayout_6">
+         <item>
+          <layout class="QVBoxLayout" name="verticalLayout_9">
+           <item>
+            <widget class="QGroupBox" name="groupBox_9">
+             <property name="title">
+              <string>Default Behavior</string>
+             </property>
+             <layout class="QVBoxLayout" name="verticalLayout_12">
+              <item>
+               <widget class="QCheckBox" name="MarkerShowMarkerData">
+                <property name="text">
+                 <string>Show data on graphs</string>
+                </property>
+               </widget>
+              </item>
+              <item>
+               <widget class="QCheckBox" name="MarkerShowAllMarkerData">
+                <property name="text">
+                 <string>Show data in all available formats</string>
+                </property>
+               </widget>
+              </item>
+             </layout>
+            </widget>
+           </item>
+           <item>
+            <layout class="QFormLayout" name="formLayout_9">
+             <item row="0" column="0">
+              <widget class="QLabel" name="label_28">
+               <property name="text">
+                <string>Positioning:</string>
+               </property>
+              </widget>
+             </item>
+             <item row="0" column="1">
+              <widget class="QComboBox" name="MarkerInterpolate">
+               <item>
+                <property name="text">
+                 <string>Snap to measurement points</string>
+                </property>
+               </item>
+               <item>
+                <property name="text">
+                 <string>Interpolate between points</string>
+                </property>
+               </item>
+              </widget>
+             </item>
+            </layout>
+           </item>
+           <item>
+            <spacer name="verticalSpacer_5">
+             <property name="orientation">
+              <enum>Qt::Vertical</enum>
+             </property>
+             <property name="sizeHint" stdset="0">
+              <size>
+               <width>20</width>
+               <height>40</height>
+              </size>
+             </property>
+            </spacer>
+           </item>
+          </layout>
+         </item>
+         <item>
+          <spacer name="horizontalSpacer_5">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+           <property name="sizeHint" stdset="0">
+            <size>
+             <width>368</width>
+             <height>20</height>
+            </size>
+           </property>
+          </spacer>
+         </item>
+        </layout>
+       </widget>
        <widget class="QWidget" name="SCPIServer">
         <layout class="QHBoxLayout" name="horizontalLayout_10">
          <item>