25QString QgsLineDensityAlgorithm::name()
const
27 return QStringLiteral(
"linedensity" );
30QString QgsLineDensityAlgorithm::displayName()
const
32 return QObject::tr(
"Line density" );
35QStringList QgsLineDensityAlgorithm::tags()
const
37 return QObject::tr(
"density,kernel,line,line density,interpolation,weight" ).split(
',' );
40QString QgsLineDensityAlgorithm::group()
const
42 return QObject::tr(
"Interpolation" );
45QString QgsLineDensityAlgorithm::groupId()
const
47 return QStringLiteral(
"interpolation" );
50void QgsLineDensityAlgorithm::initAlgorithm(
const QVariantMap & )
54 addParameter(
new QgsProcessingParameterDistance( QStringLiteral(
"RADIUS" ), QObject::tr(
"Search radius" ), 10, QStringLiteral(
"INPUT" ),
false, 0 ) );
55 addParameter(
new QgsProcessingParameterDistance( QStringLiteral(
"PIXEL_SIZE" ), QObject::tr(
"Pixel size" ), 10, QStringLiteral(
"INPUT" ),
false ) );
57 std::unique_ptr< QgsProcessingParameterString > createOptsParam = std::make_unique< QgsProcessingParameterString >( QStringLiteral(
"CREATE_OPTIONS" ), QObject::tr(
"Creation options" ), QVariant(),
false,
true );
58 createOptsParam->setMetadata( QVariantMap( {{QStringLiteral(
"widget_wrapper" ), QVariantMap( {{QStringLiteral(
"widget_type" ), QStringLiteral(
"rasteroptions" ) }} ) }} ) );
60 addParameter( createOptsParam.release() );
65QString QgsLineDensityAlgorithm::shortHelpString()
const
67 return QObject::tr(
"The line density interpolation algorithm calculates a density measure of linear features "
68 "which is obtained in a circular neighborhood within each raster cell. "
69 "First, the length of the segment of each line that is intersected by the circular neighborhood "
70 "is multiplied with the lines weight factor. In a second step, all length values are summed and "
71 "divided by the area of the circular neighborhood. This process is repeated for all raster cells."
75QgsLineDensityAlgorithm *QgsLineDensityAlgorithm::createInstance()
const
77 return new QgsLineDensityAlgorithm();
83 mSource.reset( parameterAsSource( parameters, QStringLiteral(
"INPUT" ), context ) );
87 mWeightField = parameterAsString( parameters, QStringLiteral(
"WEIGHT" ), context );
89 mPixelSize = parameterAsDouble( parameters, QStringLiteral(
"PIXEL_SIZE" ), context );
91 mSearchRadius = parameterAsDouble( parameters, QStringLiteral(
"RADIUS" ), context );
92 if ( mSearchRadius < 0.5 * mPixelSize * std::sqrt( 2 ) )
93 throw QgsProcessingException( QObject::tr(
"Raster cells must be fully contained by the search circle. Therefore, "
94 "the search radius must not be smaller than half of the pixel diagonal." ) );
96 mExtent = mSource->sourceExtent();
97 mCrs = mSource->sourceCrs();
103 const QgsPoint firstCellMidpoint =
QgsPoint( mExtent.xMinimum() + ( mPixelSize / 2 ), mExtent.yMaximum() - ( mPixelSize / 2 ) );
114 const QStringList weightName = QStringList( mWeightField );
115 const QgsFields attrFields = mSource->fields();
127 if ( !mWeightField.isEmpty() )
129 const double analysisWeight = f.
attribute( mWeightField ).toDouble();
130 mFeatureWeights.insert( f.
id(), analysisWeight );
134 const QString createOptions = parameterAsString( parameters, QStringLiteral(
"CREATE_OPTIONS" ), context ).trimmed();
135 const QString outputFile = parameterAsOutputLayer( parameters, QStringLiteral(
"OUTPUT" ), context );
136 const QFileInfo fi( outputFile );
139 const int rows = std::max( std::ceil( mExtent.height() / mPixelSize ), 1.0 );
140 const int cols = std::max( std::ceil( mExtent.width() / mPixelSize ), 1.0 );
144 const QgsRectangle rasterExtent =
QgsRectangle( mExtent.xMinimum(), mExtent.yMaximum() - ( rows * mPixelSize ), mExtent.xMinimum() + ( cols * mPixelSize ), mExtent.yMaximum() );
149 if ( !createOptions.isEmpty() )
157 if ( !provider->isValid() )
160 provider->setNoDataValue( 1, -9999 );
165 std::unique_ptr< QgsRasterBlock > rasterDataLine = std::make_unique< QgsRasterBlock >(
Qgis::DataType::Float32, cols, 1 );
167 for (
int row = 0; row < rows; row++ )
169 for (
int col = 0; col < cols; col++ )
177 mSearchGeometry.translate( mPixelSize, 0 );
179 const QList<QgsFeatureId> fids = mIndex.intersects( mSearchGeometry.boundingBox() );
181 if ( !fids.isEmpty() )
184 engine->prepareGeometry();
186 double absDensity = 0;
189 const QgsGeometry lineGeom = mIndex.geometry(
id );
191 if ( engine->intersects( lineGeom.
constGet() ) )
193 double analysisLineLength = 0;
196 analysisLineLength = mDa.measureLength(
QgsGeometry( engine->intersection( mIndex.geometry(
id ).constGet() ) ) );
205 if ( !mWeightField.isEmpty() )
207 weight = mFeatureWeights.value(
id );
210 absDensity += ( analysisLineLength * weight );
214 double lineDensity = 0;
215 if ( absDensity > 0 )
218 double analysisSearchGeometryArea = 0;
221 analysisSearchGeometryArea = mDa.measureArea( mSearchGeometry );
228 lineDensity = absDensity / analysisSearchGeometryArea;
230 rasterDataLine->setValue( 0, col, lineDensity );
235 rasterDataLine->setValue( 0, col, 0.0 );
238 feedback->
setProgress(
static_cast<double>( cellcnt ) /
static_cast<double>( totalCellcnt ) * 100 );
241 provider->writeBlock( rasterDataLine.get(), 1, 0, row );
244 mSearchGeometry.translate( ( cols - 1 ) * -mPixelSize, -mPixelSize );
248 outputs.insert( QStringLiteral(
"OUTPUT" ), outputFile );
@ VectorLine
Vector line layers.
@ Numeric
Accepts numeric fields.
@ Float32
Thirty two bit floating point (float)
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
Custom exception class for Coordinate Reference System related exceptions.
A general purpose distance and area calculator, capable of performing ellipsoid based calculations.
virtual QgsPolygon * toPolygon(unsigned int segments=36) const
Returns a segmented polygon.
Wrapper for iterator of features from vector data provider or vector layer.
bool nextFeature(QgsFeature &f)
Fetch next feature and stores in f, returns true on success.
This class wraps a request for features to a vector layer (or directly its vector data provider).
QgsFeatureRequest & setSubsetOfAttributes(const QgsAttributeList &attrs)
Set a subset of attributes that will be fetched.
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Q_INVOKABLE QVariant attribute(const QString &name) const
Lookup attribute value by attribute name.
bool isCanceled() const
Tells whether the operation has been canceled already.
void setProgress(double progress)
Sets the current progress for the feedback object.
Container of fields for a vector layer.
A geometry is the spatial representation of a feature.
const QgsAbstractGeometry * constGet() const
Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
static QgsGeometryEngine * createGeometryEngine(const QgsAbstractGeometry *geometry, double precision=0.0)
Creates and returns a new geometry engine representing the specified geometry using precision on a gr...
Point geometry type, with support for z-dimension and m-values.
Contains information about the context in which a processing algorithm is executed.
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context.
QString ellipsoid() const
Returns the ellipsoid to use for distance and area calculations.
Custom exception class for processing related exceptions.
Base class for providing feedback from a processing algorithm.
A double numeric parameter for distance values.
An input feature source (such as vector layers) parameter for processing algorithms.
A vector layer or feature source field parameter for processing algorithms.
A raster layer destination parameter, for specifying the destination path for a raster layer created ...
The raster file writer which allows you to save a raster to a new file.
static QString driverForExtension(const QString &extension)
Returns the GDAL driver name for a specified file extension.
void setOutputProviderKey(const QString &key)
Sets the name of the data provider for the raster output.
void setOutputFormat(const QString &format)
Sets the output format.
void setCreateOptions(const QStringList &list)
Sets a list of data source creation options to use when creating the output raster file.
QgsRasterDataProvider * createOneBandRaster(Qgis::DataType dataType, int width, int height, const QgsRectangle &extent, const QgsCoordinateReferenceSystem &crs) SIP_FACTORY
Create a raster file with one band without initializing the pixel data.
A rectangle specified with double values.
A spatial index for QgsFeature objects.
@ FlagStoreFeatureGeometries
Indicates that the spatial index should also store feature geometries. This requires more memory,...
unsigned long long qgssize
Qgssize is used instead of size_t, because size_t is stdlib type, unknown by SIP, and it would be har...
qint64 QgsFeatureId
64 bit feature ids negative numbers are used for uncommitted/newly added features