qgskde.h

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/***************************************************************************
  qgskde.h
  --------
  Date                 : October 2016
  Copyright            : (C) 2016 by Nyall Dawson
  Email                : nyall dot dawson at gmail 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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSKDE_H
#define QGSKDE_H
 
#include "qgsogrutils.h"
#include "qgsrectangle.h"
 
#include <QString>
 
// GDAL includes
#include <gdal.h>
#include <cpl_string.h>
#include <cpl_conv.h>
#include "qgis_analysis.h"
 
class QgsFeatureSource;
class QgsFeature;
 

class ANALYSIS_EXPORT QgsKernelDensityEstimation
{
  public:
    enum class KernelShape SIP_MONKEYPATCH_SCOPEENUM_UNNEST( QgsKernelDensityEstimation, KernelShape ) : int
    {
      Quartic SIP_MONKEYPATCH_COMPAT_NAME( KernelQuartic ) = 0,       
      Triangular SIP_MONKEYPATCH_COMPAT_NAME( KernelTriangular ),     
      Uniform SIP_MONKEYPATCH_COMPAT_NAME( KernelUniform ),           
      Triweight SIP_MONKEYPATCH_COMPAT_NAME( KernelTriweight ),       
      Epanechnikov SIP_MONKEYPATCH_COMPAT_NAME( KernelEpanechnikov ), 
    };

    enum class OutputValues SIP_MONKEYPATCH_SCOPEENUM_UNNEST( QgsKernelDensityEstimation, OutputValues ) : int
    {
      Raw SIP_MONKEYPATCH_COMPAT_NAME( OutputRaw ) = 0,   
      Scaled SIP_MONKEYPATCH_COMPAT_NAME( OutputScaled ), 
    };

    enum class Result SIP_MONKEYPATCH_SCOPEENUM_UNNEST( QgsKernelDensityEstimation, Result ) : int
    {
      Success,           
      DriverError,       
      InvalidParameters, 
      FileCreationError, 
      RasterIoError,     
    };

    struct Parameters
    {
        QgsFeatureSource *source = nullptr;

        double radius;

        QString radiusField;

        QString weightField;

        double pixelSize;

        QgsKernelDensityEstimation::KernelShape shape;

        double decayRatio;

        QgsKernelDensityEstimation::OutputValues outputValues;
    };

    QgsKernelDensityEstimation( const Parameters &parameters, const QString &outputFile, const QString &outputFormat );
 
    QgsKernelDensityEstimation( const QgsKernelDensityEstimation &other ) = delete;
    QgsKernelDensityEstimation &operator=( const QgsKernelDensityEstimation &other ) = delete;

    Result run();

    Result prepare();

    Result addFeature( const QgsFeature &feature );

    Result finalise();
 
  private:
    double calculateKernelValue( double distance, double bandwidth, KernelShape shape, OutputValues outputType ) const;
    double uniformKernel( double distance, double bandwidth, OutputValues outputType ) const;
    double quarticKernel( double distance, double bandwidth, OutputValues outputType ) const;
    double triweightKernel( double distance, double bandwidth, OutputValues outputType ) const;
    double epanechnikovKernel( double distance, double bandwidth, OutputValues outputType ) const;
    double triangularKernel( double distance, double bandwidth, OutputValues outputType ) const;
 
    QgsRectangle calculateBounds() const;
 
    QgsFeatureSource *mSource = nullptr;
 
    QString mOutputFile;
    QString mOutputFormat;
 
    int mRadiusField = -1;
    int mWeightField = -1;
    double mRadius;
    double mPixelSize;
    QgsRectangle mBounds;
 
    KernelShape mShape;
    double mDecay;
    OutputValues mOutputValues;
 
    int mBufferSize = -1;
 
    gdal::dataset_unique_ptr mDatasetH;
    GDALRasterBandH mRasterBandH = nullptr;

    bool createEmptyLayer( GDALDriverH driver, const QgsRectangle &bounds, int rows, int columns ) const;
    int radiusSizeInPixels( double radius ) const;
 
#ifdef SIP_RUN
    QgsKernelDensityEstimation( const QgsKernelDensityEstimation &other );
#endif
};
 
#endif // QGSKDE_H