QMap< QString, QString > QgsMapToolIdentify::featureDerivedAttributes( QgsFeature *feature, QgsMapLayer *layer, const QgsPoint& layerPoint )
{
// Calculate derived attributes and insert:
// measure distance or area depending on geometry type
QMap< QString, QString > derivedAttributes;
// init distance/area calculator
QString ellipsoid = QgsProject::instance()->ellipsoid();
QgsDistanceArea calc;
calc.setEllipsoidalMode( mCanvas->hasCrsTransformEnabled() );
calc.setEllipsoid( ellipsoid );
calc.setSourceCrs( layer->crs().srsid() );
QgsWkbTypes::Type wkbType = QgsWkbTypes::NoGeometry;
QgsWkbTypes::GeometryType geometryType = QgsWkbTypes::NullGeometry;
QgsVertexId vId;
QgsPointV2 closestPoint;
if ( feature->hasGeometry() )
{
geometryType = feature->geometry().type();
wkbType = feature->geometry().geometry()->wkbType();
//find closest vertex to clicked point
closestPoint = QgsGeometryUtils::closestVertex( *feature->geometry().geometry(), QgsPointV2( layerPoint.x(), layerPoint.y() ), vId );
}
if ( QgsWkbTypes::isMultiType( wkbType ) )
{
QString str = QLocale::system().toString( static_cast<const QgsGeometryCollection*>( feature->geometry().geometry() )->numGeometries() );
derivedAttributes.insert( tr( "Parts" ), str );
str = QLocale::system().toString( vId.part + 1 );
derivedAttributes.insert( tr( "Part number" ), str );
}
if ( geometryType == QgsWkbTypes::LineGeometry )
{
double dist = calc.measureLength( feature->geometry() );
dist = calc.convertLengthMeasurement( dist, displayDistanceUnits() );
QString str = formatDistance( dist );
derivedAttributes.insert( tr( "Length" ), str );
const QgsCurve* curve = dynamic_cast< const QgsCurve* >( feature->geometry().geometry() );
if ( curve )
{
str = QLocale::system().toString( curve->nCoordinates() );
derivedAttributes.insert( tr( "Vertices" ), str );
//add details of closest vertex to identify point
closestVertexAttributes( *curve, vId, layer, derivedAttributes );
// Add the start and end points in as derived attributes
QgsPoint pnt = mCanvas->mapSettings().layerToMapCoordinates( layer, QgsPoint( curve->startPoint().x(), curve->startPoint().y() ) );
str = formatXCoordinate( pnt );
derivedAttributes.insert( tr( "firstX", "attributes get sorted; translation for lastX should be lexically larger than this one" ), str );
str = formatYCoordinate( pnt );
derivedAttributes.insert( tr( "firstY" ), str );
pnt = mCanvas->mapSettings().layerToMapCoordinates( layer, QgsPoint( curve->endPoint().x(), curve->endPoint().y() ) );
str = formatXCoordinate( pnt );
derivedAttributes.insert( tr( "lastX", "attributes get sorted; translation for firstX should be lexically smaller than this one" ), str );
str = formatYCoordinate( pnt );
derivedAttributes.insert( tr( "lastY" ), str );
}
}
else if ( geometryType == QgsWkbTypes::PolygonGeometry )
{
double area = calc.measureArea( feature->geometry() );
area = calc.convertAreaMeasurement( area, displayAreaUnits() );
QString str = formatArea( area );
derivedAttributes.insert( tr( "Area" ), str );
double perimeter = calc.measurePerimeter( feature->geometry() );
perimeter = calc.convertLengthMeasurement( perimeter, displayDistanceUnits() );
str = formatDistance( perimeter );
derivedAttributes.insert( tr( "Perimeter" ), str );
str = QLocale::system().toString( feature->geometry().geometry()->nCoordinates() );
derivedAttributes.insert( tr( "Vertices" ), str );
//add details of closest vertex to identify point
closestVertexAttributes( *feature->geometry().geometry(), vId, layer, derivedAttributes );
}
else if ( geometryType == QgsWkbTypes::PointGeometry &&
QgsWkbTypes::flatType( wkbType ) == QgsWkbTypes::Point )
{
// Include the x and y coordinates of the point as a derived attribute
QgsPoint pnt = mCanvas->mapSettings().layerToMapCoordinates( layer, feature->geometry().asPoint() );
QString str = formatXCoordinate( pnt );
derivedAttributes.insert( "X", str );
str = formatYCoordinate( pnt );
derivedAttributes.insert( "Y", str );
if ( QgsWkbTypes::hasZ( wkbType ) )
{
str = QLocale::system().toString( static_cast<const QgsPointV2*>( feature->geometry().geometry() )->z(), 'g', 10 );
derivedAttributes.insert( "Z", str );
}
if ( QgsWkbTypes::hasM( wkbType ) )
{
str = QLocale::system().toString( static_cast<const QgsPointV2*>( feature->geometry().geometry() )->m(), 'g', 10 );
derivedAttributes.insert( "M", str );
}
}
return derivedAttributes;
}
void TestQgsDistanceArea::measureAreaAndUnits()
{
QgsDistanceArea da;
da.setSourceCrs( 3452 );
da.setEllipsoidalMode( false );
da.setEllipsoid( "NONE" );
QgsCoordinateReferenceSystem daCRS;
daCRS.createFromSrsId( da.sourceCrsId() );
QgsPolyline ring;
ring << QgsPoint( 0, 0 )
<< QgsPoint( 1, 0 )
<< QgsPoint( 1, 1 )
<< QgsPoint( 2, 1 )
<< QgsPoint( 2, 2 )
<< QgsPoint( 0, 2 )
<< QgsPoint( 0, 0 );
QgsPolygon poly;
poly << ring;
QgsGeometry polygon( QgsGeometry::fromPolygon( poly ) );
// We check both the measured area AND the units, in case the logic regarding
// ellipsoids and units changes in future
double area = da.measureArea( &polygon );
QgsUnitTypes::AreaUnit units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QVERIFY(( qgsDoubleNear( area, 3.0, 0.00000001 ) && units == QgsUnitTypes::AreaSquareDegrees )
|| ( qgsDoubleNear( area, 37176087091.5, 0.1 ) && units == QgsUnitTypes::AreaSquareMeters ) );
da.setEllipsoid( "WGS84" );
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QVERIFY(( qgsDoubleNear( area, 3.0, 0.00000001 ) && units == QgsUnitTypes::AreaSquareDegrees )
|| ( qgsDoubleNear( area, 37176087091.5, 0.1 ) && units == QgsUnitTypes::AreaSquareMeters ) );
da.setEllipsoidalMode( true );
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
// should always be in Meters Squared
QGSCOMPARENEAR( area, 37416879192.9, 0.1 );
QCOMPARE( units, QgsUnitTypes::AreaSquareMeters );
// test converting the resultant area
area = da.convertAreaMeasurement( area, QgsUnitTypes::AreaSquareMiles );
QGSCOMPARENEAR( area, 14446.7378, 0.001 );
// now try with a source CRS which is in feet
ring.clear();
ring << QgsPoint( 1850000, 4423000 )
<< QgsPoint( 1851000, 4423000 )
<< QgsPoint( 1851000, 4424000 )
<< QgsPoint( 1852000, 4424000 )
<< QgsPoint( 1852000, 4425000 )
<< QgsPoint( 1851000, 4425000 )
<< QgsPoint( 1850000, 4423000 );
poly.clear();
poly << ring;
polygon = QgsGeometry::fromPolygon( poly );
da.setSourceCrs( 27469 );
da.setEllipsoidalMode( false );
// measurement should be in square feet
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QGSCOMPARENEAR( area, 2000000, 0.001 );
QCOMPARE( units, QgsUnitTypes::AreaSquareFeet );
// test converting the resultant area
area = da.convertAreaMeasurement( area, QgsUnitTypes::AreaSquareYards );
QGSCOMPARENEAR( area, 222222.2222, 0.001 );
da.setEllipsoidalMode( true );
// now should be in Square Meters again
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QGSCOMPARENEAR( area, 184149.37, 1.0 );
QCOMPARE( units, QgsUnitTypes::AreaSquareMeters );
// test converting the resultant area
area = da.convertAreaMeasurement( area, QgsUnitTypes::AreaSquareYards );
QgsDebugMsg( QString( "measured %1 in sq yrds" ).arg( area ) );
QGSCOMPARENEAR( area, 220240.8172549, 0.00001 );
}