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 "qgsrectangle.h"
#include "qgsogrutils.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 KernelShape
    {
      KernelQuartic = 0, 
      KernelTriangular, 
      KernelUniform, 
      KernelTriweight, 
      KernelEpanechnikov, 
    };

    enum OutputValues
    {
      OutputRaw = 0, 
      OutputScaled, 
    };

    enum Result
    {
      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;
    int mWeightField;
    double mRadius;
    double mPixelSize;
    QgsRectangle mBounds;

    KernelShape mShape;
    double mDecay;
    OutputValues mOutputValues;

    int mBufferSize;

    gdal::dataset_unique_ptr mDatasetH;
    GDALRasterBandH mRasterBandH;

    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