QGIS/src/analysis/processing/qgsalgorithmcheckgeometrysliverpolygon.cpp
2025-09-18 12:48:55 +10:00

250 lines
11 KiB
C++

/***************************************************************************
qgsalgorithmcheckgeometrysliverpolygon.cpp
---------------------
begin : April 2025
copyright : (C) 2025 by Jacky Volpes
email : jacky dot volpes at oslandia dot com
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#include "qgsalgorithmcheckgeometrysliverpolygon.h"
#include "qgsgeometrycheckcontext.h"
#include "qgsgeometrycheckerror.h"
#include "qgsgeometrysliverpolygoncheck.h"
#include "qgspoint.h"
#include "qgsvectorlayer.h"
#include "qgsvectordataproviderfeaturepool.h"
///@cond PRIVATE
QString QgsGeometryCheckSliverPolygonAlgorithm::name() const
{
return QStringLiteral( "checkgeometrysliverpolygon" );
}
QString QgsGeometryCheckSliverPolygonAlgorithm::displayName() const
{
return QObject::tr( "Sliver polygons" );
}
QString QgsGeometryCheckSliverPolygonAlgorithm::shortDescription() const
{
return QObject::tr( "Detects sliver polygons that are too thin." );
}
QStringList QgsGeometryCheckSliverPolygonAlgorithm::tags() const
{
return QObject::tr( "check,geometry,sliver,polygon" ).split( ',' );
}
QString QgsGeometryCheckSliverPolygonAlgorithm::group() const
{
return QObject::tr( "Check geometry" );
}
QString QgsGeometryCheckSliverPolygonAlgorithm::groupId() const
{
return QStringLiteral( "checkgeometry" );
}
QString QgsGeometryCheckSliverPolygonAlgorithm::shortHelpString() const
{
return QObject::tr( "This algorithm checks sliver polygons.\n\n"
"The thinness is the ratio between the area of the minimum square containing the polygon and the area of the polygon itself "
"(a square has a thinness value of 1).\n"
"The thinness value is between 1 and +infinity.\n"
"If a polygon has an area higher than the maximum area, it is skipped (a maximum area value of 0 means no area check).\n\n"
"Polygons having a thinness higher than the maximum thinness are errors.\n\n"
"To fix sliver polygons, use the \"Fix small polygons\" algorithm." );
}
Qgis::ProcessingAlgorithmFlags QgsGeometryCheckSliverPolygonAlgorithm::flags() const
{
return QgsProcessingAlgorithm::flags() | Qgis::ProcessingAlgorithmFlag::NoThreading;
}
QgsGeometryCheckSliverPolygonAlgorithm *QgsGeometryCheckSliverPolygonAlgorithm::createInstance() const
{
return new QgsGeometryCheckSliverPolygonAlgorithm();
}
void QgsGeometryCheckSliverPolygonAlgorithm::initAlgorithm( const QVariantMap &configuration )
{
Q_UNUSED( configuration )
addParameter( new QgsProcessingParameterFeatureSource(
QStringLiteral( "INPUT" ), QObject::tr( "Input layer" ), QList<int>() << static_cast<int>( Qgis::ProcessingSourceType::VectorPolygon )
) );
addParameter( new QgsProcessingParameterField(
QStringLiteral( "UNIQUE_ID" ), QObject::tr( "Unique feature identifier" ), QString(), QStringLiteral( "INPUT" )
) );
addParameter( new QgsProcessingParameterFeatureSink(
QStringLiteral( "ERRORS" ), QObject::tr( "Sliver polygon errors" ), Qgis::ProcessingSourceType::VectorPoint
) );
addParameter( new QgsProcessingParameterFeatureSink(
QStringLiteral( "OUTPUT" ), QObject::tr( "Sliver polygon features" ), Qgis::ProcessingSourceType::VectorPolygon, QVariant(), true, false
) );
addParameter( new QgsProcessingParameterNumber(
QStringLiteral( "MAX_THINNESS" ), QObject::tr( "Maximum thinness" ), Qgis::ProcessingNumberParameterType::Double, 20, false, 1.0
) );
addParameter( new QgsProcessingParameterNumber(
QStringLiteral( "MAX_AREA" ), QObject::tr( "Maximum area (map units squared)" ), Qgis::ProcessingNumberParameterType::Double, 0, false, 0.0
) );
std::unique_ptr<QgsProcessingParameterNumber> tolerance = std::make_unique<QgsProcessingParameterNumber>(
QStringLiteral( "TOLERANCE" ), QObject::tr( "Tolerance" ), Qgis::ProcessingNumberParameterType::Integer, 8, false, 1, 13
);
tolerance->setFlags( tolerance->flags() | Qgis::ProcessingParameterFlag::Advanced );
tolerance->setHelp( QObject::tr( "The \"Tolerance\" advanced parameter defines the numerical precision of geometric operations, "
"given as an integer n, meaning that any difference smaller than 10⁻ⁿ (in map units) is considered zero." ) );
addParameter( tolerance.release() );
}
bool QgsGeometryCheckSliverPolygonAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
{
mTolerance = parameterAsInt( parameters, QStringLiteral( "TOLERANCE" ), context );
return true;
}
QgsFields QgsGeometryCheckSliverPolygonAlgorithm::outputFields()
{
QgsFields fields;
fields.append( QgsField( QStringLiteral( "gc_layerid" ), QMetaType::QString ) );
fields.append( QgsField( QStringLiteral( "gc_layername" ), QMetaType::QString ) );
fields.append( QgsField( QStringLiteral( "gc_partidx" ), QMetaType::Int ) );
fields.append( QgsField( QStringLiteral( "gc_ringidx" ), QMetaType::Int ) );
fields.append( QgsField( QStringLiteral( "gc_vertidx" ), QMetaType::Int ) );
fields.append( QgsField( QStringLiteral( "gc_errorx" ), QMetaType::Double ) );
fields.append( QgsField( QStringLiteral( "gc_errory" ), QMetaType::Double ) );
fields.append( QgsField( QStringLiteral( "gc_error" ), QMetaType::QString ) );
return fields;
}
QVariantMap QgsGeometryCheckSliverPolygonAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
{
QString dest_output;
QString dest_errors;
const std::unique_ptr<QgsProcessingFeatureSource> input( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
if ( !input )
throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
const QString uniqueIdFieldName( parameterAsString( parameters, QStringLiteral( "UNIQUE_ID" ), context ) );
const int uniqueIdFieldIdx = input->fields().indexFromName( uniqueIdFieldName );
if ( uniqueIdFieldIdx == -1 )
throw QgsProcessingException( QObject::tr( "Missing field %1 in input layer" ).arg( uniqueIdFieldName ) );
const QgsField uniqueIdField = input->fields().at( uniqueIdFieldIdx );
QgsFields fields = outputFields();
fields.append( uniqueIdField );
const std::unique_ptr<QgsFeatureSink> sink_output( parameterAsSink(
parameters, QStringLiteral( "OUTPUT" ), context, dest_output, fields, input->wkbType(), input->sourceCrs()
) );
const std::unique_ptr<QgsFeatureSink> sink_errors( parameterAsSink(
parameters, QStringLiteral( "ERRORS" ), context, dest_errors, fields, Qgis::WkbType::Point, input->sourceCrs()
) );
if ( !sink_errors )
throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "ERRORS" ) ) );
QgsProcessingMultiStepFeedback multiStepFeedback( 3, feedback );
// Test detection
QList<QgsGeometryCheckError *> checkErrors;
QStringList messages;
const double maxThinness = parameterAsDouble( parameters, QStringLiteral( "MAX_THINNESS" ), context );
const double maxArea = parameterAsDouble( parameters, QStringLiteral( "MAX_AREA" ), context );
QVariantMap configurationCheck;
configurationCheck.insert( "maxArea", maxArea );
configurationCheck.insert( "threshold", maxThinness );
const QgsProject *project = QgsProject::instance();
QgsGeometryCheckContext checkContext = QgsGeometryCheckContext( mTolerance, input->sourceCrs(), project->transformContext(), project );
const QgsGeometrySliverPolygonCheck check( &checkContext, configurationCheck );
multiStepFeedback.setCurrentStep( 1 );
feedback->setProgressText( QObject::tr( "Preparing features…" ) );
QMap<QString, QgsFeaturePool *> checkerFeaturePools;
std::unique_ptr<QgsVectorLayer> inputLayer( input->materialize( QgsFeatureRequest() ) );
QgsVectorDataProviderFeaturePool featurePool = QgsVectorDataProviderFeaturePool( inputLayer.get() );
checkerFeaturePools.insert( inputLayer->id(), &featurePool );
multiStepFeedback.setCurrentStep( 2 );
feedback->setProgressText( QObject::tr( "Collecting errors…" ) );
check.collectErrors( checkerFeaturePools, checkErrors, messages, feedback );
multiStepFeedback.setCurrentStep( 3 );
feedback->setProgressText( QObject::tr( "Exporting errors…" ) );
const double step { checkErrors.size() > 0 ? 100.0 / checkErrors.size() : 1 };
long i = 0;
feedback->setProgress( 0.0 );
for ( const QgsGeometryCheckError *error : checkErrors )
{
if ( feedback->isCanceled() )
{
break;
}
QgsFeature f;
QgsAttributes attrs = f.attributes();
attrs << error->layerId()
<< inputLayer->name()
<< error->vidx().part
<< error->vidx().ring
<< error->vidx().vertex
<< error->location().x()
<< error->location().y()
<< error->value().toString()
<< inputLayer->getFeature( error->featureId() ).attribute( uniqueIdField.name() );
f.setAttributes( attrs );
f.setGeometry( error->geometry() );
if ( sink_output && !sink_output->addFeature( f, QgsFeatureSink::FastInsert ) )
throw QgsProcessingException( writeFeatureError( sink_output.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
f.setGeometry( QgsGeometry::fromPoint( QgsPoint( error->location().x(), error->location().y() ) ) );
if ( !sink_errors->addFeature( f, QgsFeatureSink::FastInsert ) )
throw QgsProcessingException( writeFeatureError( sink_errors.get(), parameters, QStringLiteral( "ERRORS" ) ) );
i++;
feedback->setProgress( 100.0 * step * static_cast<double>( i ) );
}
// Place the point layer above the polygon layer
if ( context.willLoadLayerOnCompletion( dest_output ) && context.willLoadLayerOnCompletion( dest_errors ) )
{
context.layerToLoadOnCompletionDetails( dest_errors ).layerSortKey = 0;
context.layerToLoadOnCompletionDetails( dest_output ).layerSortKey = 1;
}
// cleanup memory of the pointed data
for ( const QgsGeometryCheckError *error : checkErrors )
{
delete error;
}
QVariantMap outputs;
if ( sink_output )
outputs.insert( QStringLiteral( "OUTPUT" ), dest_output );
outputs.insert( QStringLiteral( "ERRORS" ), dest_errors );
return outputs;
}
///@endcond