C++ QgsVectorDataProvider::geometryType方法代码示例

void QgsInterpolationDialog::on_mInputLayerComboBox_currentIndexChanged( const QString& text )
{
  Q_UNUSED( text );
  mInterpolationAttributeComboBox->clear();
  mUseZCoordCheckBox->setEnabled( false );

  //get current vector layer
  QString currentComboText = mInputLayerComboBox->currentText();
  QgsVectorLayer* theVectorLayer = vectorLayerFromName( currentComboText );

  if ( !theVectorLayer )
  {
    return;
  }

  QgsVectorDataProvider* provider = theVectorLayer->dataProvider();
  if ( !provider )
  {
    return;
  }

  //find out if the layer has 25D type
  QGis::WkbType geomType = provider->geometryType();
  if ( geomType == QGis::WKBPoint25D ||
       geomType == QGis::WKBLineString25D ||
       geomType == QGis::WKBPolygon25D ||
       geomType == QGis::WKBMultiPoint25D ||
       geomType == QGis::WKBMultiLineString25D ||
       geomType == QGis::WKBMultiPolygon25D )
  {
    mUseZCoordCheckBox->setEnabled( true );
  }

  //insert numeric attributes of layer into mInterpolationAttributesComboBox
  const QgsFields& fields = provider->fields();
  for ( int idx = 0; idx < fields.count(); ++idx )
  {
    const QgsField& currentField = fields[idx];
    QVariant::Type currentType = currentField.type();
    if ( currentType == QVariant::Int || currentType == QVariant::Double )
    {
      mInterpolationAttributeComboBox->insertItem( 0, currentField.name() );
    }
  }
}

bool QgsOverlayAnalyzer::intersection( QgsVectorLayer* layerA, QgsVectorLayer* layerB,
                                       const QString& shapefileName, bool onlySelectedFeatures,
                                       QProgressDialog* p )
{
  if ( !layerA && !layerB )
  {
    return false;
  }

  QgsVectorDataProvider* dpA = layerA->dataProvider();
  QgsVectorDataProvider* dpB = layerB->dataProvider();
  if ( !dpA && !dpB )
  {
    return false;
  }

  QGis::WkbType outputType = dpA->geometryType();
  const QgsCoordinateReferenceSystem crs = layerA->srs();
  QgsFieldMap fieldsA = dpA->fields();
  QgsFieldMap fieldsB = dpB->fields();
  combineFieldLists( fieldsA, fieldsB );

  QgsVectorFileWriter vWriter( shapefileName, dpA->encoding(), fieldsA, outputType, &crs );
  QgsFeature currentFeature;
  QgsSpatialIndex index;

  //take only selection
  if ( onlySelectedFeatures )
  {
    const QgsFeatureIds selectionB = layerB->selectedFeaturesIds();
    QgsFeatureIds::const_iterator it = selectionB.constBegin();
    for ( ; it != selectionB.constEnd(); ++it )
    {
      if ( !layerB->featureAtId( *it, currentFeature, true, true ) )
      {
        continue;
      }
      index.insertFeature( currentFeature );
    }
    //use QgsVectorLayer::featureAtId
    const QgsFeatureIds selectionA = layerA->selectedFeaturesIds();
    if ( p )
    {
      p->setMaximum( selectionA.size() );
    }
    QgsFeature currentFeature;
    int processedFeatures = 0;
    it = selectionA.constBegin();
    for ( ; it != selectionA.constEnd(); ++it )
    {
      if ( p )
      {
        p->setValue( processedFeatures );
      }

      if ( p && p->wasCanceled() )
      {
        break;
      }
      if ( !layerA->featureAtId( *it, currentFeature, true, true ) )
      {
        continue;
      }
      intersectFeature( currentFeature, &vWriter, layerB, &index );
      ++processedFeatures;
    }

    if ( p )
    {
      p->setValue( selectionA.size() );
    }
  }
  //take all features
  else
  {
    layerB->select( layerB->pendingAllAttributesList(), QgsRectangle(), true, false );
    while ( layerB->nextFeature( currentFeature ) )
    {
      index.insertFeature( currentFeature );
    }
    QgsFeature currentFeature;
    layerA->select( layerA->pendingAllAttributesList(), QgsRectangle(), true, false );

    int featureCount = layerA->featureCount();
    if ( p )
    {
      p->setMaximum( featureCount );
    }
    int processedFeatures = 0;

    while ( layerA->nextFeature( currentFeature ) )
    {
      if ( p )
      {
        p->setValue( processedFeatures );
      }
      if ( p && p->wasCanceled() )
      {
        break;
      }
//.........这里部分代码省略.........

bool QgsGeometryAnalyzer::dissolve( QgsVectorLayer* layer, const QString& shapefileName,
                                    bool onlySelectedFeatures, int uniqueIdField, QProgressDialog* p )
{
  if ( !layer )
  {
    return false;
  }
  QgsVectorDataProvider* dp = layer->dataProvider();
  if ( !dp )
  {
    return false;
  }
  bool useField = false;
  if ( uniqueIdField == -1 )
  {
    uniqueIdField = 0;
  }
  else
  {
    useField = true;
  }

  QGis::WkbType outputType = dp->geometryType();
  const QgsCoordinateReferenceSystem crs = layer->crs();

  QgsVectorFileWriter vWriter( shapefileName, dp->encoding(), layer->pendingFields(), outputType, &crs );
  QgsFeature currentFeature;
  QMultiMap<QString, QgsFeatureId> map;

  if ( onlySelectedFeatures )
  {
    //use QgsVectorLayer::featureAtId
    const QgsFeatureIds selection = layer->selectedFeaturesIds();
    QgsFeatureIds::const_iterator it = selection.constBegin();
    for ( ; it != selection.constEnd(); ++it )
    {
      if ( !layer->getFeatures( QgsFeatureRequest().setFilterFid( *it ) ).nextFeature( currentFeature ) )
      {
        continue;
      }
      map.insert( currentFeature.attribute( uniqueIdField ).toString(), currentFeature.id() );
    }
  }
  else
  {
    QgsFeatureIterator fit = layer->getFeatures();
    while ( fit.nextFeature( currentFeature ) )
    {
      map.insert( currentFeature.attribute( uniqueIdField ).toString(), currentFeature.id() );
    }
  }

  QgsGeometry *dissolveGeometry = 0; //dissolve geometry
  QMultiMap<QString, QgsFeatureId>::const_iterator jt = map.constBegin();
  QgsFeature outputFeature;
  while ( jt != map.constEnd() )
  {
    QString currentKey = jt.key();
    int processedFeatures = 0;
    bool first = true;
    //take only selection
    if ( onlySelectedFeatures )
    {
      //use QgsVectorLayer::featureAtId
      const QgsFeatureIds selection = layer->selectedFeaturesIds();
      if ( p )
      {
        p->setMaximum( selection.size() );
      }
      while ( jt != map.constEnd() && ( jt.key() == currentKey || !useField ) )
      {
        if ( p && p->wasCanceled() )
        {
          break;
        }
        if ( selection.contains( jt.value() ) )
        {
          if ( p )
          {
            p->setValue( processedFeatures );
          }
          if ( !layer->getFeatures( QgsFeatureRequest().setFilterFid( jt.value() ) ).nextFeature( currentFeature ) )
          {
            continue;
          }
          if ( first )
          {
            outputFeature.setAttributes( currentFeature.attributes() );
            first = false;
          }
          dissolveFeature( currentFeature, processedFeatures, &dissolveGeometry );
          ++processedFeatures;
        }
        ++jt;
      }
    }
    //take all features
    else
    {
      int featureCount = layer->featureCount();
//.........这里部分代码省略.........

bool QgsGeometryAnalyzer::simplify( QgsVectorLayer* layer,
                                    const QString& shapefileName,
                                    double tolerance,
                                    bool onlySelectedFeatures,
                                    QProgressDialog *p )
{
  if ( !layer )
  {
    return false;
  }

  QgsVectorDataProvider* dp = layer->dataProvider();
  if ( !dp )
  {
    return false;
  }

  QGis::WkbType outputType = dp->geometryType();
  const QgsCoordinateReferenceSystem crs = layer->crs();

  QgsVectorFileWriter vWriter( shapefileName, dp->encoding(), layer->pendingFields(), outputType, &crs );
  QgsFeature currentFeature;

  //take only selection
  if ( onlySelectedFeatures )
  {
    //use QgsVectorLayer::featureAtId
    const QgsFeatureIds selection = layer->selectedFeaturesIds();
    if ( p )
    {
      p->setMaximum( selection.size() );
    }

    int processedFeatures = 0;
    QgsFeatureIds::const_iterator it = selection.constBegin();
    for ( ; it != selection.constEnd(); ++it )
    {
      if ( p )
      {
        p->setValue( processedFeatures );
      }

      if ( p && p->wasCanceled() )
      {
        break;
      }
      if ( !layer->getFeatures( QgsFeatureRequest().setFilterFid( *it ) ).nextFeature( currentFeature ) )
      {
        continue;
      }
      simplifyFeature( currentFeature, &vWriter, tolerance );
      ++processedFeatures;
    }

    if ( p )
    {
      p->setValue( selection.size() );
    }
  }
  //take all features
  else
  {
    QgsFeatureIterator fit = layer->getFeatures();

    int featureCount = layer->featureCount();
    if ( p )
    {
      p->setMaximum( featureCount );
    }
    int processedFeatures = 0;

    while ( fit.nextFeature( currentFeature ) )
    {
      if ( p )
      {
        p->setValue( processedFeatures );
      }
      if ( p && p->wasCanceled() )
      {
        break;
      }
      simplifyFeature( currentFeature, &vWriter, tolerance );
      ++processedFeatures;
    }
    if ( p )
    {
      p->setValue( featureCount );
    }
  }

  return true;
}