当前位置: 首页>>代码示例>>C++>>正文

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

本文整理汇总了C++中QgsVectorDataProvider::encoding方法的典型用法代码示例。如果您正苦于以下问题：C++ QgsVectorDataProvider::encoding方法的具体用法？C++ QgsVectorDataProvider::encoding怎么用？C++ QgsVectorDataProvider::encoding使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类QgsVectorDataProvider的用法示例。


在下文中一共展示了QgsVectorDataProvider::encoding方法的6个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。

示例1: convexHull

bool QgsGeometryAnalyzer::convexHull( 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;
  }
  QgsFieldMap fields;
  fields.insert( 0 , QgsField( QString( "UID" ), QVariant::String ) );
  fields.insert( 1 , QgsField( QString( "AREA" ), QVariant::Double ) );
  fields.insert( 2 , QgsField( QString( "PERIM" ), QVariant::Double ) );

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

  QgsVectorFileWriter vWriter( shapefileName, dp->encoding(), fields, outputType, &crs );
  QgsFeature currentFeature;
  QgsGeometry* dissolveGeometry = 0; //dissolve geometry
  QMultiMap<QString, int> map;

  if ( onlySelectedFeatures )
  {
    //use QgsVectorLayer::featureAtId
    const QgsFeatureIds selection = layer->selectedFeaturesIds();
    QgsFeatureIds::const_iterator it = selection.constBegin();
    for ( ; it != selection.constEnd(); ++it )
    {
#if 0
      if ( p )
      {
        p->setValue( processedFeatures );
      }
      if ( p && p->wasCanceled() )
      {
        // break; // it may be better to do something else here?
        return false;
      }
#endif
      if ( !layer->featureAtId( *it, currentFeature, true, true ) )
      {
        continue;
      }
      map.insert( currentFeature.attributeMap()[ uniqueIdField ].toString(), currentFeature.id() );
    }
  }
  else
  {
    layer->select( layer->pendingAllAttributesList(), QgsRectangle(), true, false );
    while ( layer->nextFeature( currentFeature ) )
    {
#if 0
      if ( p )
      {
        p->setValue( processedFeatures );
      }
      if ( p && p->wasCanceled() )
      {
        // break; // it may be better to do something else here?
        return false;
      }
#endif
      map.insert( currentFeature.attributeMap()[ uniqueIdField ].toString(), currentFeature.id() );
    }
  }

  QMultiMap<QString, int>::const_iterator jt = map.constBegin();
  while ( jt != map.constEnd() )
  {
    QString currentKey = jt.key();
    int processedFeatures = 0;
    //take only selection
    if ( onlySelectedFeatures )
    {
      //use QgsVectorLayer::featureAtId
      const QgsFeatureIds selection = layer->selectedFeaturesIds();
      if ( p )
      {
        p->setMaximum( selection.size() );
      }
      processedFeatures = 0;
      while ( jt != map.constEnd() && ( jt.key() == currentKey || !useField ) )
      {
        if ( p && p->wasCanceled() )
        {
          break;
        }
//.........这里部分代码省略.........
开发者ID:RealworldSystems，项目名称:Quantum-GIS，代码行数:101，代码来源:qgsgeometryanalyzer.cpp

示例2: simplify

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(), dp->fields(), 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->featureAtId( *it, currentFeature, true, true ) )
      {
        continue;
      }
      simplifyFeature( currentFeature, &vWriter, tolerance );
      ++processedFeatures;
    }

    if ( p )
    {
      p->setValue( selection.size() );
    }
  }
  //take all features
  else
  {
    layer->select( layer->pendingAllAttributesList(), QgsRectangle(), true, false );


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

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

  return true;
}
开发者ID:RealworldSystems，项目名称:Quantum-GIS，代码行数:90，代码来源:qgsgeometryanalyzer.cpp

示例3: extent

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

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

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

  QgsFieldMap fields;
  fields.insert( 0 , QgsField( QString( "MINX" ), QVariant::Double ) );
  fields.insert( 1 , QgsField( QString( "MINY" ), QVariant::Double ) );
  fields.insert( 2 , QgsField( QString( "MAXX" ), QVariant::Double ) );
  fields.insert( 3 , QgsField( QString( "MAXY" ), QVariant::Double ) );
  fields.insert( 4 , QgsField( QString( "CNTX" ), QVariant::Double ) );
  fields.insert( 5 , QgsField( QString( "CNTY" ), QVariant::Double ) );
  fields.insert( 6 , QgsField( QString( "AREA" ), QVariant::Double ) );
  fields.insert( 7 , QgsField( QString( "PERIM" ), QVariant::Double ) );
  fields.insert( 8 , QgsField( QString( "HEIGHT" ), QVariant::Double ) );
  fields.insert( 9 , QgsField( QString( "WIDTH" ), QVariant::Double ) );

  QgsVectorFileWriter vWriter( shapefileName, dp->encoding(), fields, outputType, &crs );

  QgsRectangle rect;
  if ( onlySelectedFeatures )  // take only selection
  {
    rect = layer->boundingBoxOfSelected();
  }
  else
  {
    rect = layer->extent();
  }

  double minx = rect.xMinimum();
  double miny = rect.yMinimum();
  double maxx = rect.xMaximum();
  double maxy = rect.yMaximum();
  double height = rect.height();
  double width = rect.width();
  double cntx = minx + ( width / 2.0 );
  double cnty = miny + ( height / 2.0 );
  double area = width * height;
  double perim = ( 2 * width ) + ( 2 * height );

  QgsFeature feat;
  QgsAttributeMap map;
  map.insert( 0 , QVariant( minx ) );
  map.insert( 1 , QVariant( miny ) );
  map.insert( 2 , QVariant( maxx ) );
  map.insert( 3 , QVariant( maxy ) );
  map.insert( 4 , QVariant( cntx ) );
  map.insert( 5 , QVariant( cnty ) );
  map.insert( 6 , QVariant( area ) );
  map.insert( 7 , QVariant( perim ) );
  map.insert( 8 , QVariant( height ) );
  map.insert( 9 , QVariant( width ) );
  feat.setAttributeMap( map );
  feat.setGeometry( QgsGeometry::fromRect( rect ) );
  vWriter.addFeature( feat );
  return true;
}
开发者ID:RealworldSystems，项目名称:Quantum-GIS，代码行数:69，代码来源:qgsgeometryanalyzer.cpp

示例4: buffer

bool QgsGeometryAnalyzer::buffer( QgsVectorLayer* layer, const QString& shapefileName, double bufferDistance,
                                  bool onlySelectedFeatures, bool dissolve, int bufferDistanceField, QProgressDialog* p )
{
    if ( !layer )
    {
        return false;
    }

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

    QGis::WkbType outputType = QGis::WKBPolygon;
    if ( dissolve )
    {
        outputType = QGis::WKBMultiPolygon;
    }
    QgsCoordinateReferenceSystem crs = layer->crs();

    QgsVectorFileWriter vWriter( shapefileName, dp->encoding(), layer->fields(), outputType, &crs );
    QgsFeature currentFeature;
    QgsGeometry *dissolveGeometry = nullptr; //dissolve geometry (if dissolve enabled)

    //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;
            }
            bufferFeature( currentFeature, processedFeatures, &vWriter, dissolve, &dissolveGeometry, bufferDistance, bufferDistanceField );
            ++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;
            }
            bufferFeature( currentFeature, processedFeatures, &vWriter, dissolve, &dissolveGeometry, bufferDistance, bufferDistanceField );
            ++processedFeatures;
        }
        if ( p )
        {
            p->setValue( featureCount );
        }
    }

    if ( dissolve )
    {
        QgsFeature dissolveFeature;
        if ( !dissolveGeometry )
        {
            QgsDebugMsg( "no dissolved geometry - should not happen" );
            return false;
        }
//.........这里部分代码省略.........
开发者ID:rouault，项目名称:Quantum-GIS，代码行数:101，代码来源:qgsgeometryanalyzer.cpp

示例5: dissolve

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();
    QgsCoordinateReferenceSystem crs = layer->crs();

    QgsVectorFileWriter vWriter( shapefileName, dp->encoding(), layer->fields(), 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 = nullptr; //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.........
开发者ID:rouault，项目名称:Quantum-GIS，代码行数:101，代码来源:qgsgeometryanalyzer.cpp

示例6: centroids

bool QgsGeometryAnalyzer::centroids( QgsVectorLayer* layer, const QString& shapefileName,
                                     bool onlySelectedFeatures, QProgressDialog* p )
{
    if ( !layer )
    {
        QgsDebugMsg( "No layer passed to centroids" );
        return false;
    }

    QgsVectorDataProvider* dp = layer->dataProvider();
    if ( !dp )
    {
        QgsDebugMsg( "No data provider for layer passed to centroids" );
        return false;
    }

    QGis::WkbType outputType = QGis::WKBPoint;
    QgsCoordinateReferenceSystem crs = layer->crs();

    QgsVectorFileWriter vWriter( shapefileName, dp->encoding(), layer->fields(), 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;
            }
            centroidFeature( currentFeature, &vWriter );
            ++processedFeatures;
        }

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

        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;
            }
            centroidFeature( currentFeature, &vWriter );
            ++processedFeatures;
        }
        if ( p )
        {
            p->setValue( featureCount );
        }
    }

    return true;
}
开发者ID:rouault，项目名称:Quantum-GIS，代码行数:91，代码来源:qgsgeometryanalyzer.cpp


注：本文中的QgsVectorDataProvider::encoding方法示例由纯净天空整理自Github/MSDocs等开源代码及文档管理平台，相关代码片段筛选自各路编程大神贡献的开源项目，源码版权归原作者所有，传播和使用请参考对应项目的License；未经允许，请勿转载。