Respect project ellipsoid and unit settings in virtual fields

Fix #12622, #4252
qgis · Feb 16, 2016 · 4094bae · 4094bae
1 parent 2265eb9
commit 4094bae
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Showing 3 changed files with 79 additions and 1 deletion.
diff --git a/src/core/qgsvectorlayerfeatureiterator.cpp b/src/core/qgsvectorlayerfeatureiterator.cpp
@@ -23,13 +23,17 @@
 #include "qgsvectorlayer.h"
 #include "qgsvectorlayerjoinbuffer.h"
 #include "qgsexpressioncontext.h"
+#include "qgsdistancearea.h"
+#include "qgsproject.h"
 
 QgsVectorLayerFeatureSource::QgsVectorLayerFeatureSource( QgsVectorLayer *layer )
+    : mCrsId( 0 )
 {
   mProviderFeatureSource = layer->dataProvider()->featureSource();
   mFields = layer->fields();
   mJoinBuffer = layer->mJoinBuffer->clone();
   mExpressionFieldBuffer = new QgsExpressionFieldBuffer( *layer->mExpressionFieldBuffer );
+  mCrsId = layer->crs().srsid();
 
   mCanBeSimplified = layer->hasGeometryType() && layer->geometryType() != QGis::Point;
 
@@ -544,6 +548,15 @@ void QgsVectorLayerFeatureIterator::prepareExpressions()
       {
         int oi = mSource->mFields.fieldOriginIndex( i );
         QgsExpression* exp = new QgsExpression( exps[oi].cachedExpression );
+
+        QgsDistanceArea da;
+        da.setSourceCrs( mSource->mCrsId );
+        da.setEllipsoidalMode( true );
+        da.setEllipsoid( QgsProject::instance()->readEntry( "Measure", "/Ellipsoid", GEO_NONE ) );
+        exp->setGeomCalculator( da );
+        exp->setDistanceUnits( QgsProject::instance()->distanceUnits() );
+        exp->setAreaUnits( QgsProject::instance()->areaUnits() );
+
         exp->prepare( mExpressionContext.data() );
         mExpressionFieldInfo.insert( i, exp );
 

diff --git a/src/core/qgsvectorlayerfeatureiterator.h b/src/core/qgsvectorlayerfeatureiterator.h
@@ -66,6 +66,8 @@ class QgsVectorLayerFeatureSource : public QgsAbstractFeatureSource
     QList<QgsField> mAddedAttributes;
     QgsChangedAttributesMap mChangedAttributeValues;
     QgsAttributeList mDeletedAttributeIds;
+
+    long mCrsId;
 };
 
 

diff --git a/tests/src/python/test_qgsvectorlayer.py b/tests/src/python/test_qgsvectorlayer.py
@@ -29,7 +29,10 @@
                        QgsMapLayerRegistry,
                        QgsVectorJoinInfo,
                        QgsSymbolV2,
-                       QgsSingleSymbolRendererV2)
+                       QgsSingleSymbolRendererV2,
+                       QgsCoordinateReferenceSystem,
+                       QgsProject,
+                       QgsUnitTypes)
 from qgis.testing import (start_app,
                           unittest
                           )
@@ -975,6 +978,66 @@ def test_ExpressionField(self):
 
         self.assertEquals(layer.pendingFields().count(), cnt)
 
+    def test_ExpressionFieldEllipsoidLengthCalculation(self):
+        #create a temporary layer
+        temp_layer = QgsVectorLayer("LineString?crs=epsg:3111&field=pk:int", "vl", "memory")
+        assert temp_layer.isValid()
+        f1 = QgsFeature(temp_layer.dataProvider().fields(), 1)
+        f1.setAttribute("pk", 1)
+        f1.setGeometry(QgsGeometry.fromPolyline([QgsPoint(2484588, 2425722), QgsPoint(2482767, 2398853)]))
+        temp_layer.dataProvider().addFeatures([f1])
+
+        # set project CRS and ellipsoid
+        srs = QgsCoordinateReferenceSystem(3111, QgsCoordinateReferenceSystem.EpsgCrsId)
+        QgsProject.instance().writeEntry("SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4())
+        QgsProject.instance().writeEntry("SpatialRefSys", "/ProjectCRSID", srs.srsid())
+        QgsProject.instance().writeEntry("SpatialRefSys", "/ProjectCrs", srs.authid())
+        QgsProject.instance().writeEntry("Measure", "/Ellipsoid", "WGS84")
+        QgsProject.instance().writeEntry("Measurement", "/DistanceUnits", QgsUnitTypes.encodeUnit(QGis.Meters))
+
+        idx = temp_layer.addExpressionField('$length', QgsField('length', QVariant.Double))
+
+        # check value
+        f = temp_layer.getFeatures().next()
+        expected = 26932.156
+        self.assertAlmostEqual(f['length'], expected, 3)
+
+        # change project length unit, check calculation respects unit
+        QgsProject.instance().writeEntry("Measurement", "/DistanceUnits", QgsUnitTypes.encodeUnit(QGis.Feet))
+        f = temp_layer.getFeatures().next()
+        expected = 88360.0918635
+        self.assertAlmostEqual(f['length'], expected, 3)
+
+    def test_ExpressionFieldEllipsoidAreaCalculation(self):
+        #create a temporary layer
+        temp_layer = QgsVectorLayer("Polygon?crs=epsg:3111&field=pk:int", "vl", "memory")
+        assert temp_layer.isValid()
+        f1 = QgsFeature(temp_layer.dataProvider().fields(), 1)
+        f1.setAttribute("pk", 1)
+        f1.setGeometry(QgsGeometry.fromPolygon([[QgsPoint(2484588, 2425722), QgsPoint(2482767, 2398853), QgsPoint(2520109, 2397715), QgsPoint(2520792, 2425494), QgsPoint(2484588, 2425722)]]))
+        temp_layer.dataProvider().addFeatures([f1])
+
+        # set project CRS and ellipsoid
+        srs = QgsCoordinateReferenceSystem(3111, QgsCoordinateReferenceSystem.EpsgCrsId)
+        QgsProject.instance().writeEntry("SpatialRefSys", "/ProjectCRSProj4String", srs.toProj4())
+        QgsProject.instance().writeEntry("SpatialRefSys", "/ProjectCRSID", srs.srsid())
+        QgsProject.instance().writeEntry("SpatialRefSys", "/ProjectCrs", srs.authid())
+        QgsProject.instance().writeEntry("Measure", "/Ellipsoid", "WGS84")
+        QgsProject.instance().writeEntry("Measurement", "/AreaUnits", QgsUnitTypes.encodeUnit(QgsUnitTypes.SquareMeters))
+
+        idx = temp_layer.addExpressionField('$area', QgsField('area', QVariant.Double))
+
+        # check value
+        f = temp_layer.getFeatures().next()
+        expected = 1009089817.0
+        self.assertAlmostEqual(f['area'], expected, 0)
+
+        # change project area unit, check calculation respects unit
+        QgsProject.instance().writeEntry("Measurement", "/AreaUnits", QgsUnitTypes.encodeUnit(QgsUnitTypes.SquareMiles))
+        f = temp_layer.getFeatures().next()
+        expected = 389.6117565069
+        self.assertAlmostEqual(f['area'], expected, 3)
+
     def test_ExpressionFilter(self):
         layer = createLayerWithOnePoint()