diff --git a/src/Mod/Sketcher/App/CMakeLists.txt b/src/Mod/Sketcher/App/CMakeLists.txt
index e1f39d46e8..7697574d8f 100644
--- a/src/Mod/Sketcher/App/CMakeLists.txt
+++ b/src/Mod/Sketcher/App/CMakeLists.txt
@@ -12,6 +12,7 @@ include_directories(
     ${CMAKE_CURRENT_BINARY_DIR}/..
     ${Boost_INCLUDE_DIRS}
     ${OCC_INCLUDE_DIR}
+    ${QT_QTCORE_INCLUDE_DIR}
     ${ZLIB_INCLUDE_DIR}
     ${PYTHON_INCLUDE_PATH}
     ${XERCESC_INCLUDE_DIR}
diff --git a/src/Mod/Sketcher/App/SketchObjectPyImp.cpp b/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
index 26b9589f2a..0c71ba7521 100644
--- a/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
+++ b/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
@@ -31,6 +31,8 @@
 #include <Base/GeometryPyCXX.h>
 #include <Base/VectorPy.h>
 #include <Base/AxisPy.h>
+#include <Base/Tools.h>
+#include <Base/QuantityPy.h>
 #include <App/Document.h>
 
 // inclusion of the generated files (generated out of SketchObjectSFPy.xml)
@@ -239,8 +241,22 @@ PyObject* SketchObjectPy::setDatum(PyObject *args)
 {
     double Datum;
     int    Index;
-    if (!PyArg_ParseTuple(args, "id", &Index, &Datum))
-        return 0;
+    PyObject* object;
+    Base::Quantity Quantity;
+    if (PyArg_ParseTuple(args,"iO!", &Index, &(Base::QuantityPy::Type), &object)) {
+        Quantity = *(static_cast<Base::QuantityPy*>(object)->getQuantityPtr());
+        if (Quantity.getUnit() == Base::Unit::Angle)
+            //Datum = Quantity.getValueAs(Base::Quantity::Radian);
+            Datum = Base::toRadians<double>(Quantity.getValue());
+        else
+            Datum = Quantity.getValue();
+    }
+    else {
+        PyErr_Clear();
+        if (!PyArg_ParseTuple(args, "id", &Index, &Datum))
+            return 0;
+        Quantity.setValue(Datum);
+    }
 
     int err=this->getSketchObjectPtr()->setDatum(Index, Datum);
     if (err) {
@@ -250,13 +266,13 @@ PyObject* SketchObjectPy::setDatum(PyObject *args)
         else if (err == -3)
             str << "Cannot set the datum because the sketch contains conflicting constraints";
         else if (err == -2)
-            str << "Datum " << Datum << " for the constraint with index " << Index << " is invalid";
+            str << "Datum " << (const char*)Quantity.getUserString().toUtf8() << " for the constraint with index " << Index << " is invalid";
         else if (err == -4)
             str << "Negative datum values are not valid for the constraint with index " << Index;
         else if (err == -5)
             str << "Zero is not a valid datum for the constraint with index " << Index;
         else
-            str << "Unexpected problem at setting datum " << Datum << " for the constraint with index " << Index;
+            str << "Unexpected problem at setting datum " << (const char*)Quantity.getUserString().toUtf8() << " for the constraint with index " << Index;
         PyErr_SetString(PyExc_ValueError, str.str().c_str());
         return 0;
     }
diff --git a/src/Mod/Sketcher/Gui/EditDatumDialog.cpp b/src/Mod/Sketcher/Gui/EditDatumDialog.cpp
index 5c8a31c33b..5bb30ee463 100644
--- a/src/Mod/Sketcher/Gui/EditDatumDialog.cpp
+++ b/src/Mod/Sketcher/Gui/EditDatumDialog.cpp
@@ -124,13 +124,7 @@ void EditDatumDialog::exec(bool atCursor)
                 // save the value for the history 
                 ui_ins_datum.labelEdit->pushToHistory();
 
-                double newDatum;
-                if (Constr->Type == Sketcher::Angle)
-                    newDatum = Base::toRadians<double>(newQuant.getValue());
-                else 
-                    newDatum = newQuant.getValue();
-
-
+                double newDatum = newQuant.getValue();
                 if (Constr->Type == Sketcher::Angle ||
                     ((Constr->Type == Sketcher::DistanceX || Constr->Type == Sketcher::DistanceY) &&
                      Constr->FirstPos == Sketcher::none || Constr->Second != Sketcher::Constraint::GeoUndef)) {
@@ -143,9 +137,9 @@ void EditDatumDialog::exec(bool atCursor)
 
                 try {
                     Gui::Command::openCommand("Modify sketch constraints");
-                    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.setDatum(%i,%f)",
+                    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.setDatum(%i,App.Units.Quantity('%f %s'))",
                                 sketch->getNameInDocument(),
-                                ConstrNbr, newDatum);
+                                ConstrNbr, newDatum, (const char*)newQuant.getUnit().getString().toUtf8());
                     Gui::Command::commitCommand();
                     Gui::Command::updateActive();
                 }