diff --git a/python/core/qgsproject.sip b/python/core/qgsproject.sip
index 3d59dda19521..6371c8914871 100644
--- a/python/core/qgsproject.sip
+++ b/python/core/qgsproject.sip
@@ -64,6 +64,38 @@ class QgsProject : QObject
      */
     QFileInfo fileInfo() const;
 
+    /**
+     * Returns the project's native coordinate reference system.
+     * @note added in QGIS 2.18
+     * @see setCrs()
+     * @see ellipsoid()
+     */
+    QgsCoordinateReferenceSystem crs() const;
+
+    /**
+     * Sets the project's native coordinate reference system.
+     * @note added in QGIS 2.18
+     * @see crs()
+     * @see setEllipsoid()
+     */
+    void setCrs( const QgsCoordinateReferenceSystem& crs );
+
+    /**
+     * Returns a proj string representing the project's ellipsoid setting, eg "WGS84".
+     * @see setEllipsoid()
+     * @see crs()
+     * @note added in QGIS 2.18
+     */
+    QString ellipsoid() const;
+
+    /**
+     * Sets the project's ellipsoid from a proj string representation, eg "WGS84".
+     * @see ellipsoid()
+     * @see setCrs()
+     * @note added in QGIS 2.18
+     */
+    void setEllipsoid( const QString& ellipsoid );
+
     /** Clear the project - removes all settings and resets it back to an empty, default state.
      * @note added in 2.4
      */
@@ -258,16 +290,33 @@ class QgsProject : QObject
 
     /** Convenience function to query default distance measurement units for project.
      * @note added in QGIS 2.14
+     * @see setDistanceUnits()
      * @see areaUnits()
      */
     QgsUnitTypes::DistanceUnit distanceUnits() const;
 
+    /**
+     * Sets the default distance measurement units for the project.
+     * @note added in QGIS 2.18
+     * @see distanceUnits()
+     * @see setAreaUnits()
+     */
+    void setDistanceUnits( QgsUnitTypes::DistanceUnit unit );
+
     /** Convenience function to query default area measurement units for project.
      * @note added in QGIS 2.14
      * @see distanceUnits()
      */
     QgsUnitTypes::AreaUnit areaUnits() const;
 
+    /**
+     * Sets the default area measurement units for the project.
+     * @note added in QGIS 2.18
+     * @see areaUnits()
+     * @see setDistanceUnits()
+     */
+    void setAreaUnits( QgsUnitTypes::AreaUnit unit );
+
     /** Return project's home path
       @return home path of project (or QString::null if not set) */
     QString homePath() const;
diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
index 59cf1c5b53e2..c5245645da16 100644
--- a/src/app/qgisapp.cpp
+++ b/src/app/qgisapp.cpp
@@ -4435,9 +4435,7 @@ void QgisApp::fileNew( bool thePromptToSaveFlag, bool forceBlank )
   QgsCoordinateReferenceSystem srs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( defCrs );
   mMapCanvas->setDestinationCrs( srs );
   // write the projections _proj string_ to project settings
-  prj->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  prj->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  prj->writeEntry( "SpatialRefSys", "/ProjectCRSID", static_cast< int >( srs.srsid() ) );
+  prj->setCrs( srs );
   prj->setDirty( false );
   if ( srs.mapUnits() != QgsUnitTypes::DistanceUnknownUnit )
   {
@@ -7306,7 +7304,7 @@ void QgisApp::selectByForm()
 
   myDa.setSourceCrs( vlayer->crs().srsid() );
   myDa.setEllipsoidalMode( mMapCanvas->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   QgsAttributeEditorContext context;
   context.setDistanceArea( myDa );
@@ -8582,6 +8580,7 @@ void QgisApp::setProjectCrsFromLayer()
   QgsCoordinateReferenceSystem crs = mLayerTreeView->currentLayer()->crs();
   mMapCanvas->freeze();
   mMapCanvas->setDestinationCrs( crs );
+  QgsProject::instance()->setCrs( crs );
   if ( crs.mapUnits() != QgsUnitTypes::DistanceUnknownUnit )
   {
     mMapCanvas->setMapUnits( crs.mapUnits() );
diff --git a/src/app/qgisappinterface.cpp b/src/app/qgisappinterface.cpp
index c6bf04add48d..636a6bef9a81 100644
--- a/src/app/qgisappinterface.cpp
+++ b/src/app/qgisappinterface.cpp
@@ -681,7 +681,7 @@ QgsAttributeDialog* QgisAppInterface::getFeatureForm( QgsVectorLayer *l, QgsFeat
 
   myDa.setSourceCrs( l->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   QgsAttributeEditorContext context;
   context.setDistanceArea( myDa );
diff --git a/src/app/qgsattributeactionpropertiesdialog.cpp b/src/app/qgsattributeactionpropertiesdialog.cpp
index 41c7e9124cea..f859dc0ca918 100644
--- a/src/app/qgsattributeactionpropertiesdialog.cpp
+++ b/src/app/qgsattributeactionpropertiesdialog.cpp
@@ -52,7 +52,7 @@ QgsAttributeActionPropertiesDialog::QgsAttributeActionPropertiesDialog( QgsActio
   QgsDistanceArea myDa;
   myDa.setSourceCrs( mLayer->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   mFieldExpression->setLayer( mLayer );
   mFieldExpression->setGeomCalculator( myDa );
@@ -81,7 +81,7 @@ QgsAttributeActionPropertiesDialog::QgsAttributeActionPropertiesDialog( QgsVecto
   QgsDistanceArea myDa;
   myDa.setSourceCrs( mLayer->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   mFieldExpression->setLayer( mLayer );
   mFieldExpression->setGeomCalculator( myDa );
diff --git a/src/app/qgsattributetabledialog.cpp b/src/app/qgsattributetabledialog.cpp
index a84483bb498c..e10005d4728d 100644
--- a/src/app/qgsattributetabledialog.cpp
+++ b/src/app/qgsattributetabledialog.cpp
@@ -126,7 +126,7 @@ QgsAttributeTableDialog::QgsAttributeTableDialog( QgsVectorLayer *theLayer, QWid
 
   myDa->setSourceCrs( mLayer->crs() );
   myDa->setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa->setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa->setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   mEditorContext.setDistanceArea( *myDa );
   mEditorContext.setVectorLayerTools( QgisApp::instance()->vectorLayerTools() );
@@ -559,7 +559,7 @@ void QgsAttributeTableDialog::filterExpressionBuilder()
   QgsDistanceArea myDa;
   myDa.setSourceCrs( mLayer->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
   dlg.setGeomCalculator( myDa );
 
   if ( dlg.exec() == QDialog::Accepted )
@@ -920,7 +920,7 @@ void QgsAttributeTableDialog::setFilterExpression( const QString& filterString,
 
   myDa.setSourceCrs( mLayer->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   // parse search string and build parsed tree
   QgsExpression filterExpression( filter );
diff --git a/src/app/qgsdiagramproperties.cpp b/src/app/qgsdiagramproperties.cpp
index 81d21d5024c1..6be3c268ba83 100644
--- a/src/app/qgsdiagramproperties.cpp
+++ b/src/app/qgsdiagramproperties.cpp
@@ -178,7 +178,7 @@ QgsDiagramProperties::QgsDiagramProperties( QgsVectorLayer* layer, QWidget* pare
   QgsDistanceArea myDa;
   myDa.setSourceCrs( mLayer->crs().srsid() );
   myDa.setEllipsoidalMode( mMapCanvas->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
   mSizeFieldExpressionWidget->setGeomCalculator( myDa );
 
   //insert all attributes into the combo boxes
@@ -871,7 +871,7 @@ QString QgsDiagramProperties::showExpressionBuilder( const QString& initialExpre
   QgsDistanceArea myDa;
   myDa.setSourceCrs( mLayer->crs().srsid() );
   myDa.setEllipsoidalMode( mMapCanvas->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
   dlg.setGeomCalculator( myDa );
 
   if ( dlg.exec() == QDialog::Accepted )
diff --git a/src/app/qgsfeatureaction.cpp b/src/app/qgsfeatureaction.cpp
index a02a5c78f82f..6905984e68fc 100644
--- a/src/app/qgsfeatureaction.cpp
+++ b/src/app/qgsfeatureaction.cpp
@@ -57,7 +57,7 @@ QgsAttributeDialog *QgsFeatureAction::newDialog( bool cloneFeature )
 
   myDa.setSourceCrs( mLayer->crs() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   context.setDistanceArea( myDa );
   context.setVectorLayerTools( QgisApp::instance()->vectorLayerTools() );
diff --git a/src/app/qgsfieldcalculator.cpp b/src/app/qgsfieldcalculator.cpp
index 5dd7bc383493..75e15357ba98 100644
--- a/src/app/qgsfieldcalculator.cpp
+++ b/src/app/qgsfieldcalculator.cpp
@@ -60,7 +60,7 @@ QgsFieldCalculator::QgsFieldCalculator( QgsVectorLayer* vl, QWidget* parent )
   QgsDistanceArea myDa;
   myDa.setSourceCrs( vl->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
   builder->setGeomCalculator( myDa );
 
   //default values for field width and precision
@@ -160,7 +160,7 @@ void QgsFieldCalculator::accept()
 
   myDa.setSourceCrs( mVectorLayer->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   QString calcString = builder->expressionText();
   QgsExpression exp( calcString );
diff --git a/src/app/qgslabelinggui.cpp b/src/app/qgslabelinggui.cpp
index 2b582fbcc7b9..9b16629bb295 100644
--- a/src/app/qgslabelinggui.cpp
+++ b/src/app/qgslabelinggui.cpp
@@ -590,7 +590,7 @@ void QgsLabelingGui::init()
   QgsDistanceArea myDa;
   myDa.setSourceCrs( mLayer->crs().srsid() );
   myDa.setEllipsoidalMode( QgisApp::instance()->mapCanvas()->mapSettings().hasCrsTransformEnabled() );
-  myDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
   mFieldExpressionWidget->setGeomCalculator( myDa );
 
   // set placement methods page based on geometry type
diff --git a/src/app/qgsmaptoolmeasureangle.cpp b/src/app/qgsmaptoolmeasureangle.cpp
index ecae82aaa536..37e71af1ef69 100644
--- a/src/app/qgsmaptoolmeasureangle.cpp
+++ b/src/app/qgsmaptoolmeasureangle.cpp
@@ -181,7 +181,7 @@ void QgsMapToolMeasureAngle::updateSettings()
 
 void QgsMapToolMeasureAngle::configureDistanceArea()
 {
-  QString ellipsoidId = QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE );
+  QString ellipsoidId = QgsProject::instance()->ellipsoid();
   mDa.setSourceCrs( mCanvas->mapSettings().destinationCrs().srsid() );
   mDa.setEllipsoid( ellipsoidId );
   // Only use ellipsoidal calculation when project wide transformation is enabled.
diff --git a/src/app/qgsmeasuredialog.cpp b/src/app/qgsmeasuredialog.cpp
index 3668457d8b6f..25d6e799a4ed 100644
--- a/src/app/qgsmeasuredialog.cpp
+++ b/src/app/qgsmeasuredialog.cpp
@@ -79,7 +79,7 @@ void QgsMeasureDialog::updateSettings()
   mDistanceUnits = QgsProject::instance()->distanceUnits();
   mAreaUnits = QgsProject::instance()->areaUnits();
   mDa.setSourceCrs( mTool->canvas()->mapSettings().destinationCrs().srsid() );
-  mDa.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  mDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
   // Only use ellipsoidal calculation when project wide transformation is enabled.
   if ( mTool->canvas()->mapSettings().hasCrsTransformEnabled() )
   {
diff --git a/src/app/qgsprojectproperties.cpp b/src/app/qgsprojectproperties.cpp
index 3321544567b6..81ca3f6d8244 100644
--- a/src/app/qgsprojectproperties.cpp
+++ b/src/app/qgsprojectproperties.cpp
@@ -783,9 +783,7 @@ void QgsProjectProperties::apply()
     QgsDebugMsg( QString( "Selected CRS " ) + srs.description() );
     // write the currently selected projections _proj string_ to project settings
     QgsDebugMsg( QString( "SpatialRefSys/ProjectCRSProj4String: %1" ).arg( projectionSelector->selectedProj4String() ) );
-    QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", projectionSelector->selectedProj4String() );
-    QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) projectionSelector->selectedCrsId() );
-    QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", projectionSelector->selectedAuthId() );
+    QgsProject::instance()->setCrs( srs );
 
     // Set the map units to the projected coordinates if we are projecting
     if ( isProjected() )
@@ -837,10 +835,10 @@ void QgsProjectProperties::apply()
   emit displayPrecisionChanged();
 
   QgsUnitTypes::DistanceUnit distanceUnits = static_cast< QgsUnitTypes::DistanceUnit >( mDistanceUnitsCombo->currentData().toInt() );
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( distanceUnits ) );
+  QgsProject::instance()->setDistanceUnits( distanceUnits );
 
   QgsUnitTypes::AreaUnit areaUnits = static_cast< QgsUnitTypes::AreaUnit >( mAreaUnitsCombo->currentData().toInt() );
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( areaUnits ) );
+  QgsProject::instance()->setAreaUnits( areaUnits );
 
   QgsProject::instance()->writeEntry( "Paths", "/Absolute", cbxAbsolutePath->currentIndex() == 0 );
 
@@ -855,13 +853,13 @@ void QgsProjectProperties::apply()
       major = QLocale::system().toDouble( leSemiMajor->text() );
       minor = QLocale::system().toDouble( leSemiMinor->text() );
     }
-    QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "PARAMETER:%1:%2" )
-                                        .arg( major, 0, 'g', 17 )
-                                        .arg( minor, 0, 'g', 17 ) );
+    QgsProject::instance()->setEllipsoid( QString( "PARAMETER:%1:%2" )
+                                          .arg( major, 0, 'g', 17 )
+                                          .arg( minor, 0, 'g', 17 ) );
   }
   else
   {
-    QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", mEllipsoidList[ mEllipsoidIndex ].acronym );
+    QgsProject::instance()->setEllipsoid( mEllipsoidList[ mEllipsoidIndex ].acronym );
   }
 
   //set the color for selections
@@ -2001,7 +1999,7 @@ void QgsProjectProperties::projectionSelectorInitialized()
   QgsDebugMsg( "Setting up ellipsoid" );
 
   // Reading ellipsoid from setttings
-  QStringList mySplitEllipsoid = QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ).split( ':' );
+  QStringList mySplitEllipsoid = QgsProject::instance()->ellipsoid().split( ':' );
 
   int myIndex = 0;
   for ( int i = 0; i < mEllipsoidList.length(); i++ )
diff --git a/src/core/composer/qgscomposerhtml.cpp b/src/core/composer/qgscomposerhtml.cpp
index 0a9f0082604b..5a6d113c8e25 100644
--- a/src/core/composer/qgscomposerhtml.cpp
+++ b/src/core/composer/qgscomposerhtml.cpp
@@ -548,7 +548,7 @@ void QgsComposerHtml::setExpressionContext( const QgsFeature &feature, QgsVector
   {
     mDistanceArea->setEllipsoidalMode( mComposition->mapSettings().hasCrsTransformEnabled() );
   }
-  mDistanceArea->setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  mDistanceArea->setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   // create JSON representation of feature
   QgsJSONExporter exporter( layer );
diff --git a/src/core/composer/qgscomposerlabel.cpp b/src/core/composer/qgscomposerlabel.cpp
index 01cb62334d91..41e101eef243 100644
--- a/src/core/composer/qgscomposerlabel.cpp
+++ b/src/core/composer/qgscomposerlabel.cpp
@@ -265,7 +265,7 @@ void QgsComposerLabel::refreshExpressionContext()
     mDistanceArea->setSourceCrs( mComposition->mapSettings().destinationCrs().srsid() );
   }
   mDistanceArea->setEllipsoidalMode( mComposition->mapSettings().hasCrsTransformEnabled() );
-  mDistanceArea->setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  mDistanceArea->setEllipsoid( QgsProject::instance()->ellipsoid() );
   contentChanged();
 
   update();
diff --git a/src/core/composer/qgscomposerscalebar.cpp b/src/core/composer/qgscomposerscalebar.cpp
index 96a5ddc08e2d..a84fa4398031 100644
--- a/src/core/composer/qgscomposerscalebar.cpp
+++ b/src/core/composer/qgscomposerscalebar.cpp
@@ -304,7 +304,7 @@ double QgsComposerScaleBar::mapWidth() const
     QgsDistanceArea da;
     da.setEllipsoidalMode( mComposition->mapSettings().hasCrsTransformEnabled() );
     da.setSourceCrs( mComposition->mapSettings().destinationCrs().srsid() );
-    da.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", "WGS84" ) );
+    da.setEllipsoid( QgsProject::instance()->ellipsoid() );
 
     QgsUnitTypes::DistanceUnit units = QgsUnitTypes::DistanceMeters;
     double measure = da.measureLine( QgsPoint( composerMapRect.xMinimum(), composerMapRect.yMinimum() ),
diff --git a/src/core/qgsproject.cpp b/src/core/qgsproject.cpp
index c7989001f89a..3b5932ecc381 100644
--- a/src/core/qgsproject.cpp
+++ b/src/core/qgsproject.cpp
@@ -444,6 +444,36 @@ QFileInfo QgsProject::fileInfo() const
   return QFileInfo( imp_->file );
 }
 
+QgsCoordinateReferenceSystem QgsProject::crs() const
+{
+  QgsCoordinateReferenceSystem projectCrs;
+  long currentCRS = readNumEntry( "SpatialRefSys", "/ProjectCRSID", -1 );
+  if ( currentCRS != -1 )
+  {
+    projectCrs = QgsCoordinateReferenceSystem::fromSrsId( currentCRS );
+  }
+  return projectCrs;
+}
+
+void QgsProject::setCrs( const QgsCoordinateReferenceSystem &crs )
+{
+  writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", crs.toProj4() );
+  writeEntry( "SpatialRefSys", "/ProjectCRSID", static_cast< int >( crs.srsid() ) );
+  writeEntry( "SpatialRefSys", "/ProjectCrs", crs.authid() );
+  setDirty( true );
+}
+
+QString QgsProject::ellipsoid() const
+{
+  return readEntry( "Measure", "/Ellipsoid", GEO_NONE );
+}
+
+void QgsProject::setEllipsoid( const QString& ellipsoid )
+{
+  writeEntry( "Measure", "/Ellipsoid", ellipsoid );
+  setDirty( true );
+}
+
 void QgsProject::clear()
 {
   imp_->clear();
@@ -2108,6 +2138,11 @@ QgsUnitTypes::DistanceUnit QgsProject::distanceUnits() const
   return ok ? type : QgsUnitTypes::DistanceMeters;
 }
 
+void QgsProject::setDistanceUnits( QgsUnitTypes::DistanceUnit unit )
+{
+  writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( unit ) );
+}
+
 QgsUnitTypes::AreaUnit QgsProject::areaUnits() const
 {
   QString areaUnitString = QgsProject::instance()->readEntry( "Measurement", "/AreaUnits", QString() );
@@ -2121,6 +2156,11 @@ QgsUnitTypes::AreaUnit QgsProject::areaUnits() const
   return ok ? type : QgsUnitTypes::AreaSquareMeters;
 }
 
+void QgsProject::setAreaUnits( QgsUnitTypes::AreaUnit unit )
+{
+  writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( unit ) );
+}
+
 void QgsProjectBadLayerDefaultHandler::handleBadLayers( const QList<QDomNode>& /*layers*/, const QDomDocument& /*projectDom*/ )
 {
   // just ignore any bad layers
diff --git a/src/core/qgsproject.h b/src/core/qgsproject.h
index e838ab6cb82a..017f5e1b3bc6 100644
--- a/src/core/qgsproject.h
+++ b/src/core/qgsproject.h
@@ -34,6 +34,7 @@
 #include "qgsunittypes.h"
 #include "qgsprojectversion.h"
 #include "qgsexpressioncontextgenerator.h"
+#include "qgscoordinatereferencesystem.h"
 
 class QFileInfo;
 class QDomDocument;
@@ -74,6 +75,7 @@ class CORE_EXPORT QgsProject : public QObject, public QgsExpressionContextGenera
     Q_PROPERTY( QStringList nonIdentifiableLayers READ nonIdentifiableLayers WRITE setNonIdentifiableLayers NOTIFY nonIdentifiableLayersChanged )
     Q_PROPERTY( QString fileName READ fileName WRITE setFileName NOTIFY fileNameChanged )
     Q_PROPERTY( QString homePath READ homePath NOTIFY homePathChanged )
+    Q_PROPERTY( QgsCoordinateReferenceSystem crs READ crs WRITE setCrs )
 
   public:
 
@@ -120,6 +122,38 @@ class CORE_EXPORT QgsProject : public QObject, public QgsExpressionContextGenera
      */
     QFileInfo fileInfo() const;
 
+    /**
+     * Returns the project's native coordinate reference system.
+     * @note added in QGIS 2.18
+     * @see setCrs()
+     * @see ellipsoid()
+     */
+    QgsCoordinateReferenceSystem crs() const;
+
+    /**
+     * Sets the project's native coordinate reference system.
+     * @note added in QGIS 2.18
+     * @see crs()
+     * @see setEllipsoid()
+     */
+    void setCrs( const QgsCoordinateReferenceSystem& crs );
+
+    /**
+     * Returns a proj string representing the project's ellipsoid setting, eg "WGS84".
+     * @see setEllipsoid()
+     * @see crs()
+     * @note added in QGIS 2.18
+     */
+    QString ellipsoid() const;
+
+    /**
+     * Sets the project's ellipsoid from a proj string representation, eg "WGS84".
+     * @see ellipsoid()
+     * @see setCrs()
+     * @note added in QGIS 2.18
+     */
+    void setEllipsoid( const QString& ellipsoid );
+
     /** Clear the project - removes all settings and resets it back to an empty, default state.
      * @note added in 2.4
      */
@@ -314,16 +348,33 @@ class CORE_EXPORT QgsProject : public QObject, public QgsExpressionContextGenera
 
     /** Convenience function to query default distance measurement units for project.
      * @note added in QGIS 2.14
+     * @see setDistanceUnits()
      * @see areaUnits()
      */
     QgsUnitTypes::DistanceUnit distanceUnits() const;
 
+    /**
+     * Sets the default distance measurement units for the project.
+     * @note added in QGIS 2.18
+     * @see distanceUnits()
+     * @see setAreaUnits()
+     */
+    void setDistanceUnits( QgsUnitTypes::DistanceUnit unit );
+
     /** Convenience function to query default area measurement units for project.
      * @note added in QGIS 2.14
      * @see distanceUnits()
      */
     QgsUnitTypes::AreaUnit areaUnits() const;
 
+    /**
+     * Sets the default area measurement units for the project.
+     * @note added in QGIS 2.18
+     * @see areaUnits()
+     * @see setDistanceUnits()
+     */
+    void setAreaUnits( QgsUnitTypes::AreaUnit unit );
+
     /** Return project's home path
       @return home path of project (or QString::null if not set) */
     QString homePath() const;
diff --git a/src/core/qgsvectorlayerfeatureiterator.cpp b/src/core/qgsvectorlayerfeatureiterator.cpp
index 7aeb2a24a206..5014532951f5 100644
--- a/src/core/qgsvectorlayerfeatureiterator.cpp
+++ b/src/core/qgsvectorlayerfeatureiterator.cpp
@@ -548,7 +548,7 @@ void QgsVectorLayerFeatureIterator::prepareExpression( int fieldIdx )
   QgsDistanceArea da;
   da.setSourceCrs( mSource->mCrsId );
   da.setEllipsoidalMode( true );
-  da.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+  da.setEllipsoid( QgsProject::instance()->ellipsoid() );
   exp->setGeomCalculator( &da );
   exp->setDistanceUnits( QgsProject::instance()->distanceUnits() );
   exp->setAreaUnits( QgsProject::instance()->areaUnits() );
diff --git a/src/gui/layertree/qgslayertreemapcanvasbridge.cpp b/src/gui/layertree/qgslayertreemapcanvasbridge.cpp
index 179bea4ab307..81c2edbd229d 100644
--- a/src/gui/layertree/qgslayertreemapcanvasbridge.cpp
+++ b/src/gui/layertree/qgslayertreemapcanvasbridge.cpp
@@ -20,6 +20,7 @@
 #include "qgsmaplayer.h"
 #include "qgsvectorlayer.h"
 #include "qgsmapcanvas.h"
+#include "qgsproject.h"
 
 QgsLayerTreeMapCanvasBridge::QgsLayerTreeMapCanvasBridge( QgsLayerTreeGroup *root, QgsMapCanvas *canvas, QObject* parent )
     : QObject( parent )
@@ -146,6 +147,7 @@ void QgsLayerTreeMapCanvasBridge::setCanvasLayers()
         if ( layerNode->layer()->isSpatial() )
         {
           mCanvas->setDestinationCrs( layerNode->layer()->crs() );
+          QgsProject::instance()->setCrs( layerNode->layer()->crs() );
           mCanvas->setMapUnits( layerNode->layer()->crs().mapUnits() );
           break;
         }
@@ -182,6 +184,7 @@ void QgsLayerTreeMapCanvasBridge::setCanvasLayers()
       if ( layerNode->layer() && layerNode->layer()->crs().isValid() && layerNode->layer()->crs() != mFirstCRS )
       {
         mCanvas->setDestinationCrs( mFirstCRS );
+        QgsProject::instance()->setCrs( mFirstCRS );
         mCanvas->setCrsTransformEnabled( true );
         break;
       }
diff --git a/src/gui/qgsmaptoolidentify.cpp b/src/gui/qgsmaptoolidentify.cpp
index 7b5d07b30f57..5b5325017633 100644
--- a/src/gui/qgsmaptoolidentify.cpp
+++ b/src/gui/qgsmaptoolidentify.cpp
@@ -352,7 +352,7 @@ QMap< QString, QString > QgsMapToolIdentify::featureDerivedAttributes( QgsFeatur
   QMap< QString, QString > derivedAttributes;
 
   // init distance/area calculator
-  QString ellipsoid = QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE );
+  QString ellipsoid = QgsProject::instance()->ellipsoid();
   QgsDistanceArea calc;
   calc.setEllipsoidalMode( mCanvas->hasCrsTransformEnabled() );
   calc.setEllipsoid( ellipsoid );
diff --git a/src/gui/qgsowssourceselect.cpp b/src/gui/qgsowssourceselect.cpp
index cc386b8113fd..952553e1a914 100644
--- a/src/gui/qgsowssourceselect.cpp
+++ b/src/gui/qgsowssourceselect.cpp
@@ -93,15 +93,11 @@ QgsOWSSourceSelect::QgsOWSSourceSelect( const QString& service, QWidget * parent
   {
     connect( mAddButton, SIGNAL( clicked() ), this, SLOT( addClicked() ) );
     //set the current project CRS if available
-    long currentCRS = QgsProject::instance()->readNumEntry( "SpatialRefSys", "/ProjectCRSID", -1 );
-    if ( currentCRS != -1 )
+    QgsCoordinateReferenceSystem currentRefSys = QgsProject::instance()->crs();
+    //convert CRS id to epsg
+    if ( currentRefSys.isValid() )
     {
-      //convert CRS id to epsg
-      QgsCoordinateReferenceSystem currentRefSys = QgsCoordinateReferenceSystem::fromSrsId( currentCRS );
-      if ( currentRefSys.isValid() )
-      {
-        mSelectedCRS = currentRefSys.authid();
-      }
+      mSelectedCRS = currentRefSys.authid();
     }
   }
   else
@@ -383,8 +379,7 @@ void QgsOWSSourceSelect::on_mChangeCRSButton_clicked()
   mySelector->setMessage();
   mySelector->setOgcWmsCrsFilter( mSelectedLayersCRSs );
 
-  QString myDefaultCrs = QgsProject::instance()->readEntry( "SpatialRefSys", "/ProjectCrs", GEO_EPSG_CRS_AUTHID );
-  QgsCoordinateReferenceSystem defaultCRS = QgsCoordinateReferenceSystem::fromOgcWmsCrs( myDefaultCrs );
+  QgsCoordinateReferenceSystem defaultCRS = QgsProject::instance()->crs();
   if ( defaultCRS.isValid() )
   {
     mySelector->setSelectedCrsId( defaultCRS.srsid() );
diff --git a/src/gui/qgsprojectionselectionwidget.cpp b/src/gui/qgsprojectionselectionwidget.cpp
index eb1a7ba8640e..e507b7872f01 100644
--- a/src/gui/qgsprojectionselectionwidget.cpp
+++ b/src/gui/qgsprojectionselectionwidget.cpp
@@ -40,8 +40,7 @@ QgsProjectionSelectionWidget::QgsProjectionSelectionWidget( QWidget *parent )
   {
     //only show project CRS if OTF reprojection is enabled - otherwise the
     //CRS stored in the project can be misleading
-    QString projectCrsString = QgsProject::instance()->readEntry( "SpatialRefSys", "/ProjectCrs" );
-    mProjectCrs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( projectCrsString );
+    mProjectCrs = QgsProject::instance()->crs();
     addProjectCrsOption();
   }
 
diff --git a/src/gui/qgssourceselectdialog.cpp b/src/gui/qgssourceselectdialog.cpp
index e5c2b4211dfc..ef495638ce83 100644
--- a/src/gui/qgssourceselectdialog.cpp
+++ b/src/gui/qgssourceselectdialog.cpp
@@ -194,9 +194,8 @@ QString QgsSourceSelectDialog::getPreferredCrs( const QSet<QString>& crsSet ) co
   }
 
   //first: project CRS
-  long ProjectCRSID = QgsProject::instance()->readNumEntry( "SpatialRefSys", "/ProjectCRSID", -1 );
+  QgsCoordinateReferenceSystem projectRefSys = QgsProject::instance()->crs();
   //convert to EPSG
-  QgsCoordinateReferenceSystem projectRefSys = QgsCoordinateReferenceSystem::fromSrsId( ProjectCRSID );
   QString ProjectCRS;
   if ( projectRefSys.isValid() )
   {
diff --git a/src/providers/wfs/qgswfssourceselect.cpp b/src/providers/wfs/qgswfssourceselect.cpp
index 3ed15d37da46..0fa4d9417070 100644
--- a/src/providers/wfs/qgswfssourceselect.cpp
+++ b/src/providers/wfs/qgswfssourceselect.cpp
@@ -179,9 +179,8 @@ QString QgsWFSSourceSelect::getPreferredCrs( const QSet<QString>& crsSet ) const
   }
 
   //first: project CRS
-  long ProjectCRSID = QgsProject::instance()->readNumEntry( "SpatialRefSys", "/ProjectCRSID", -1 );
+  QgsCoordinateReferenceSystem projectRefSys = QgsProject::instance()->crs();
   //convert to EPSG
-  QgsCoordinateReferenceSystem projectRefSys = QgsCoordinateReferenceSystem::fromSrsId( ProjectCRSID );
   QString ProjectCRS;
   if ( projectRefSys.isValid() )
   {
diff --git a/src/providers/wms/qgswmssourceselect.cpp b/src/providers/wms/qgswmssourceselect.cpp
index 1dbdcd53b19d..fb43dc1c2f41 100644
--- a/src/providers/wms/qgswmssourceselect.cpp
+++ b/src/providers/wms/qgswmssourceselect.cpp
@@ -112,15 +112,11 @@ QgsWMSSourceSelect::QgsWMSSourceSelect( QWidget * parent, Qt::WindowFlags fl, bo
     setTabOrder( lstLayers, mImageFormatGroup->button( 0 ) );
 
     //set the current project CRS if available
-    long currentCRS = QgsProject::instance()->readNumEntry( "SpatialRefSys", "/ProjectCRSID", -1 );
-    if ( currentCRS != -1 )
+    QgsCoordinateReferenceSystem currentRefSys = QgsProject::instance()->crs();
+    //convert CRS id to epsg
+    if ( currentRefSys.isValid() )
     {
-      //convert CRS id to epsg
-      QgsCoordinateReferenceSystem currentRefSys = QgsCoordinateReferenceSystem::fromSrsId( currentCRS );
-      if ( currentRefSys.isValid() )
-      {
-        mDefaultCRS = mCRS = currentRefSys.authid();
-      }
+      mDefaultCRS = mCRS = currentRefSys.authid();
     }
 
     // set up the default WMS Coordinate Reference System
@@ -616,8 +612,7 @@ void QgsWMSSourceSelect::on_btnChangeSpatialRefSys_clicked()
   mySelector->setMessage();
   mySelector->setOgcWmsCrsFilter( mCRSs );
 
-  QString myDefaultCrs = QgsProject::instance()->readEntry( "SpatialRefSys", "/ProjectCrs", GEO_EPSG_CRS_AUTHID );
-  QgsCoordinateReferenceSystem defaultCRS = QgsCoordinateReferenceSystem::fromOgcWmsCrs( myDefaultCrs );
+  QgsCoordinateReferenceSystem defaultCRS = QgsProject::instance()->crs();
   if ( defaultCRS.isValid() )
   {
     mySelector->setSelectedCrsId( defaultCRS.srsid() );
diff --git a/tests/src/app/testqgsattributetable.cpp b/tests/src/app/testqgsattributetable.cpp
index 2aac54cbdde0..b4600508fa13 100644
--- a/tests/src/app/testqgsattributetable.cpp
+++ b/tests/src/app/testqgsattributetable.cpp
@@ -87,11 +87,9 @@ void TestQgsAttributeTable::testFieldCalculation()
   // set project CRS and ellipsoid
   QgisApp::instance()->mapCanvas()->setCrsTransformEnabled( true );
   QgsCoordinateReferenceSystem srs( 3111, QgsCoordinateReferenceSystem::EpsgCrsId );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceMeters );
 
   // run length calculation
   QScopedPointer< QgsAttributeTableDialog > dlg( new QgsAttributeTableDialog( tempLayer.data() ) );
@@ -106,7 +104,7 @@ void TestQgsAttributeTable::testFieldCalculation()
   QVERIFY( qgsDoubleNear( f.attribute( "col1" ).toDouble(), expected, 0.001 ) );
 
   // change project length unit, check calculation respects unit
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceFeet ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceFeet );
   QScopedPointer< QgsAttributeTableDialog > dlg2( new QgsAttributeTableDialog( tempLayer.data() ) );
   tempLayer->startEditing();
   dlg2->runFieldCalculation( tempLayer.data(), "col1", "$length" );
@@ -140,11 +138,9 @@ void TestQgsAttributeTable::testFieldCalculationArea()
   // set project CRS and ellipsoid
   QgisApp::instance()->mapCanvas()->setCrsTransformEnabled( true );
   QgsCoordinateReferenceSystem srs( 3111, QgsCoordinateReferenceSystem::EpsgCrsId );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMeters );
 
   // run area calculation
   QScopedPointer< QgsAttributeTableDialog > dlg( new QgsAttributeTableDialog( tempLayer.data() ) );
@@ -159,7 +155,7 @@ void TestQgsAttributeTable::testFieldCalculationArea()
   QVERIFY( qgsDoubleNear( f.attribute( "col1" ).toDouble(), expected, 1.0 ) );
 
   // change project area unit, check calculation respects unit
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMiles ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMiles );
   QScopedPointer< QgsAttributeTableDialog > dlg2( new QgsAttributeTableDialog( tempLayer.data() ) );
   tempLayer->startEditing();
   dlg2->runFieldCalculation( tempLayer.data(), "col1", "$area" );
diff --git a/tests/src/app/testqgsfieldcalculator.cpp b/tests/src/app/testqgsfieldcalculator.cpp
index b81afd0ed88a..ec656a2b070f 100644
--- a/tests/src/app/testqgsfieldcalculator.cpp
+++ b/tests/src/app/testqgsfieldcalculator.cpp
@@ -87,11 +87,9 @@ void TestQgsFieldCalculator::testLengthCalculations()
   // set project CRS and ellipsoid
   QgisApp::instance()->mapCanvas()->setCrsTransformEnabled( true );
   QgsCoordinateReferenceSystem srs( 3111, QgsCoordinateReferenceSystem::EpsgCrsId );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceMeters );
 
   // run length calculation
   tempLayer->startEditing();
@@ -113,7 +111,7 @@ void TestQgsFieldCalculator::testLengthCalculations()
   QVERIFY( qgsDoubleNear( f.attribute( "col1" ).toDouble(), expected, 0.001 ) );
 
   // change project length unit, check calculation respects unit
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceFeet ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceFeet );
   tempLayer->startEditing();
   QScopedPointer< QgsFieldCalculator > calc2( new QgsFieldCalculator( tempLayer.data() ) );
   calc2->mUpdateExistingGroupBox->setChecked( true );
@@ -151,11 +149,9 @@ void TestQgsFieldCalculator::testAreaCalculations()
   // set project CRS and ellipsoid
   QgisApp::instance()->mapCanvas()->setCrsTransformEnabled( true );
   QgsCoordinateReferenceSystem srs( 3111, QgsCoordinateReferenceSystem::EpsgCrsId );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMeters );
 
   // run area calculation
   tempLayer->startEditing();
@@ -177,7 +173,7 @@ void TestQgsFieldCalculator::testAreaCalculations()
   QVERIFY( qgsDoubleNear( f.attribute( "col1" ).toDouble(), expected, 1.0 ) );
 
   // change project area unit, check calculation respects unit
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMiles ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMiles );
   tempLayer->startEditing();
   QScopedPointer< QgsFieldCalculator > calc2( new QgsFieldCalculator( tempLayer.data() ) );
   calc2->mUpdateExistingGroupBox->setChecked( true );
diff --git a/tests/src/app/testqgsmaptoolidentifyaction.cpp b/tests/src/app/testqgsmaptoolidentifyaction.cpp
index 2a4f71ae139e..399e1f51c4e3 100644
--- a/tests/src/app/testqgsmaptoolidentifyaction.cpp
+++ b/tests/src/app/testqgsmaptoolidentifyaction.cpp
@@ -130,11 +130,9 @@ void TestQgsMapToolIdentifyAction::lengthCalculation()
   canvas->setCrsTransformEnabled( true );
   canvas->setDestinationCrs( srs );
   canvas->setExtent( f1.geometry().boundingBox() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceMeters );
 
   QgsPoint mapPoint = canvas->getCoordinateTransform()->transform( 2484588, 2425722 );
 
@@ -146,7 +144,7 @@ void TestQgsMapToolIdentifyAction::lengthCalculation()
   QVERIFY( qgsDoubleNear( length, 26932.2, 0.1 ) );
 
   //check that project units are respected
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceFeet ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceFeet );
   result = action->identify( mapPoint.x(), mapPoint.y(), QList<QgsMapLayer*>() << tempLayer.data() );
   QCOMPARE( result.length(), 1 );
   derivedLength = result.at( 0 ).mDerivedAttributes[tr( "Length" )];
@@ -186,11 +184,9 @@ void TestQgsMapToolIdentifyAction::perimeterCalculation()
   canvas->setCrsTransformEnabled( true );
   canvas->setDestinationCrs( srs );
   canvas->setExtent( f1.geometry().boundingBox() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceMeters );
 
   QgsPoint mapPoint = canvas->getCoordinateTransform()->transform( 2484588, 2425722 );
 
@@ -202,7 +198,7 @@ void TestQgsMapToolIdentifyAction::perimeterCalculation()
   QCOMPARE( perimeter, 128289.074 );
 
   //check that project units are respected
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceFeet ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceFeet );
   result = action->identify( mapPoint.x(), mapPoint.y(), QList<QgsMapLayer*>() << tempLayer.data() );
   QCOMPARE( result.length(), 1 );
   derivedPerimeter = result.at( 0 ).mDerivedAttributes[tr( "Perimeter" )];
@@ -243,11 +239,9 @@ void TestQgsMapToolIdentifyAction::areaCalculation()
   canvas->setCrsTransformEnabled( true );
   canvas->setDestinationCrs( srs );
   canvas->setExtent( f1.geometry().boundingBox() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMeters );
 
   QgsPoint mapPoint = canvas->getCoordinateTransform()->transform( 2484588, 2425722 );
 
@@ -259,7 +253,7 @@ void TestQgsMapToolIdentifyAction::areaCalculation()
   QVERIFY( qgsDoubleNear( area, 1009089817.0, 1.0 ) );
 
   //check that project units are respected
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMiles ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMiles );
   result = action->identify( mapPoint.x(), mapPoint.y(), QList<QgsMapLayer*>() << tempLayer.data() );
   QCOMPARE( result.length(), 1 );
   derivedArea = result.at( 0 ).mDerivedAttributes[tr( "Area" )];
@@ -268,7 +262,7 @@ void TestQgsMapToolIdentifyAction::areaCalculation()
 
   //test unchecked "keep base units" setting
   s.setValue( "/qgis/measure/keepbaseunit", false );
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareFeet ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareFeet );
   result = action->identify( mapPoint.x(), mapPoint.y(), QList<QgsMapLayer*>() << tempLayer.data() );
   QCOMPARE( result.length(), 1 );
   derivedArea = result.at( 0 ).mDerivedAttributes[tr( "Area" )];
diff --git a/tests/src/app/testqgsmeasuretool.cpp b/tests/src/app/testqgsmeasuretool.cpp
index 00b038d1f276..84a1de0cb95f 100644
--- a/tests/src/app/testqgsmeasuretool.cpp
+++ b/tests/src/app/testqgsmeasuretool.cpp
@@ -94,11 +94,9 @@ void TestQgsMeasureTool::testLengthCalculation()
   QgsCoordinateReferenceSystem srs( 3111, QgsCoordinateReferenceSystem::EpsgCrsId );
   mCanvas->setCrsTransformEnabled( true );
   mCanvas->setDestinationCrs( srs );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceMeters );
 
   // run length calculation
   QScopedPointer< QgsMeasureTool > tool( new QgsMeasureTool( mCanvas, false ) );
@@ -117,7 +115,7 @@ void TestQgsMeasureTool::testLengthCalculation()
   QGSCOMPARENEAR( measured, expected, 0.001 );
 
   // change project length unit, check calculation respects unit
-  QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceFeet ) );
+  QgsProject::instance()->setDistanceUnits( QgsUnitTypes::DistanceFeet );
   QScopedPointer< QgsMeasureTool > tool2( new QgsMeasureTool( mCanvas, false ) );
   QScopedPointer< QgsMeasureDialog > dlg2( new QgsMeasureDialog( tool2.data() ) );
 
@@ -163,11 +161,9 @@ void TestQgsMeasureTool::testAreaCalculation()
   QgsCoordinateReferenceSystem srs( 3111, QgsCoordinateReferenceSystem::EpsgCrsId );
   mCanvas->setCrsTransformEnabled( true );
   mCanvas->setDestinationCrs( srs );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCRSID", ( int ) srs.srsid() );
-  QgsProject::instance()->writeEntry( "SpatialRefSys", "/ProjectCrs", srs.authid() );
-  QgsProject::instance()->writeEntry( "Measure", "/Ellipsoid", QString( "WGS84" ) );
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMeters ) );
+  QgsProject::instance()->setCrs( srs );
+  QgsProject::instance()->setEllipsoid( QString( "WGS84" ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMeters );
 
   // run length calculation
   QScopedPointer< QgsMeasureTool > tool( new QgsMeasureTool( mCanvas, true ) );
@@ -188,7 +184,7 @@ void TestQgsMeasureTool::testAreaCalculation()
   QGSCOMPARENEAR( measured, expected, 1.0 );
 
   // change project area unit, check calculation respects unit
-  QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaSquareMiles ) );
+  QgsProject::instance()->setAreaUnits( QgsUnitTypes::AreaSquareMiles );
   QScopedPointer< QgsMeasureTool > tool2( new QgsMeasureTool( mCanvas, true ) );
   QScopedPointer< QgsMeasureDialog > dlg2( new QgsMeasureDialog( tool2.data() ) );
 
diff --git a/tests/src/core/testqgsproject.cpp b/tests/src/core/testqgsproject.cpp
index a8ae721fba54..1421360e6e79 100644
--- a/tests/src/core/testqgsproject.cpp
+++ b/tests/src/core/testqgsproject.cpp
@@ -104,7 +104,7 @@ void TestQgsProject::testProjectUnits()
   QCOMPARE( prj->distanceUnits(), QgsUnitTypes::DistanceFeet );
 
   //test setting new units for project
-  prj->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::DistanceNauticalMiles ) );
+  prj->setDistanceUnits( QgsUnitTypes::DistanceNauticalMiles );
   QCOMPARE( prj->distanceUnits(), QgsUnitTypes::DistanceNauticalMiles );
 
   // AREA
@@ -121,7 +121,7 @@ void TestQgsProject::testProjectUnits()
   QCOMPARE( prj->areaUnits(), QgsUnitTypes::AreaSquareYards );
 
   //test setting new units for project
-  prj->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::AreaAcres ) );
+  prj->setAreaUnits( QgsUnitTypes::AreaAcres );
   QCOMPARE( prj->areaUnits(), QgsUnitTypes::AreaAcres );
 }
 
diff --git a/tests/src/python/test_qgsproject.py b/tests/src/python/test_qgsproject.py
index 9ef08523a997..9e79d01fa663 100644
--- a/tests/src/python/test_qgsproject.py
+++ b/tests/src/python/test_qgsproject.py
@@ -16,7 +16,7 @@
 
 import qgis  # NOQA
 
-from qgis.core import QgsProject, QgsMessageLog
+from qgis.core import QgsProject, QgsMessageLog, QgsUnitTypes, QgsCoordinateReferenceSystem
 
 from qgis.testing import start_app, unittest
 
@@ -111,5 +111,34 @@ def test_makeKeyTokens_(self):
     def catchMessage(self):
         self.messageCaught = True
 
+    def testCrs(self):
+        prj = QgsProject.instance()
+        prj.clear()
+
+        self.assertFalse(prj.crs().isValid())
+        prj.setCrs(QgsCoordinateReferenceSystem.fromOgcWmsCrs('EPSG:3111'))
+        self.assertEqual(prj.crs().authid(), 'EPSG:3111')
+
+    def testEllipsoid(self):
+        prj = QgsProject.instance()
+        prj.clear()
+
+        prj.setEllipsoid('WGS84')
+        self.assertEqual(prj.ellipsoid(), 'WGS84')
+
+    def testDistanceUnits(self):
+        prj = QgsProject.instance()
+        prj.clear()
+
+        prj.setDistanceUnits(QgsUnitTypes.DistanceFeet)
+        self.assertEqual(prj.distanceUnits(), QgsUnitTypes.DistanceFeet)
+
+    def testAreaUnits(self):
+        prj = QgsProject.instance()
+        prj.clear()
+
+        prj.setAreaUnits(QgsUnitTypes.AreaSquareFeet)
+        self.assertEqual(prj.areaUnits(), QgsUnitTypes.AreaSquareFeet)
+
 if __name__ == '__main__':
     unittest.main()