qgsalgorithmupslopearea.h

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/***************************************************************************
                         qgsalgorithmupslopearea.h
                         ---------------------
    begin                : September 2026
    copyright            : (C) 2026 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 QGSALGORITHMUPSLOPEAREA_H
#define QGSALGORITHMUPSLOPEAREA_H
 
 
#include "qgis_sip.h"
#include "qgsprocessingalgorithm.h"
 
#define SIP_NO_FILE


class QgsUpslopeAreaAlgorithmBase : public QgsProcessingAlgorithm
{
  public:
    QgsUpslopeAreaAlgorithmBase() = default;
 
    QString group() const override;
    QString groupId() const override;
    QStringList tags() const override;
    QList<QgsAcademicReference> academicReferences() const override;
    QList<QgsProcessingAlgorithm::ExternalLink> externalLinks() const override;
 
  protected:
    enum class Method : int
    {
      D8 = 0,    
      DInf = 1,  
      MFD = 2,   
      MDInf = 3, 
      MMDGFD = 4 
    };
 
    void addCommonParameters();
    bool prepareBase( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback );
 
    // Core flow accumulation engine
    bool calculateUpslopeArea( const std::vector<QgsPointXY> &targetPoints, QgsProcessingContext &context, QgsProcessingFeedback *feedback );
 
    static double neighborLength( int dir, double cellSizeX, double cellSizeY );
    static int neighborTo( int dir, int col, int &outCol, int row, int &outRow, int cols, int rows );
 
    void computeCellValue( const QgsRasterBlock *demBlock, int col, int row, int cols, int rows, double cellSizeX, double cellSizeY, Method method, double converge, bool contour );
    void computeD8( const QgsRasterBlock *demBlock, int col, int row, int cols, int rows, double cellSizeX, double cellSizeY );
    void computeDInf( const QgsRasterBlock *demBlock, int col, int row, int cols, int rows, double cellSizeX, double cellSizeY );
    void computeMFD( const QgsRasterBlock *demBlock, int col, int row, int cols, int rows, double cellSizeX, double cellSizeY, double converge, bool contour );
    void computeMMDGFD( const QgsRasterBlock *demBlock, int col, int row, int cols, int rows, double cellSizeX, double cellSizeY, bool contour );
    void computeMDInf( const QgsRasterBlock *demBlock, int col, int row, int cols, int rows, double cellSizeX, double cellSizeY, double converge );
 
    std::unique_ptr<QgsRasterInterface> mDemProvider;
    QgsCoordinateReferenceSystem mDemCrs;
    std::unique_ptr<QgsRasterInterface> mRouteProvider;
 
    int mCols = 0;
    int mRows = 0;
    double mCellSizeX = 0.0;
    double mCellSizeY = 0.0;
    double mDemNoData = -9999.0;
    double mRouteNoData = -9999.0;
    QgsRectangle mExtent;
 
    std::vector<double> mRouteData;
    std::vector<double> mFlowData;
 
    Method mMethod = Method::MFD;
    double mConvergence = 1.1;
    bool mMfdContour = false;
    QString mOutputPath;
    QString mOutputFormat;
    QString mCreationOptions;
    double mOutputNoData = -9999;
};

class QgsUpslopeAreaPointAlgorithm : public QgsUpslopeAreaAlgorithmBase
{
  public:
    QgsUpslopeAreaPointAlgorithm();
 
    QString name() const override;
    QString displayName() const override;
    QString shortDescription() const override;
    QString shortHelpString() const override;
    QgsProcessingAlgorithm *createInstance() const override;
 
    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
 
  protected:
    bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
    QVariantMap processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
};

class QgsUpslopeAreaLayerAlgorithm : public QgsUpslopeAreaAlgorithmBase
{
  public:
    QgsUpslopeAreaLayerAlgorithm();
 
    QString name() const override;
    QString displayName() const override;
    QString shortDescription() const override;
    QString shortHelpString() const override;
    QgsProcessingAlgorithm *createInstance() const override;
 
    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
 
  protected:
    bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
    QVariantMap processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
};

 
#endif // QGSALGORITHMUPSLOPEAREA_H