Subversion Repositories public iLand

/********************************************************************************************

**    iLand - an individual based forest landscape and disturbance model

**    http://iland.boku.ac.at

**    Copyright (C) 2009-  Werner Rammer, Rupert Seidl

**

**    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 3 of the License, or

**    (at your option) any later version.

**

**    This program is distributed in the hope that it will be useful,

**    but WITHOUT ANY WARRANTY; without even the implied warranty of

**    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

**    GNU General Public License for more details.

**

**    You should have received a copy of the GNU General Public License

**    along with this program.  If not, see <http://www.gnu.org/licenses/>.

********************************************************************************************/

#ifndef GRASSCOVER_H

#define GRASSCOVER_H

#include "expression.h"

#include "grid.h"

#include "layeredgrid.h"

#include "random.h"

class GrassCoverLayers; // forwared

// define the data type that is used to store the grass-levels

// use unsigned char for 1 byte (or quint8), unsigned short int (quint16) for two bytes per pixel

#define grass_grid_type qint16

/**

 * @brief The GrassCover class specifies the limiting effect of ground vegetation (grasses, herbs)

 * on the regeneration success of the tree species.

 * The GrassCover model is very simple and operates on a 2x2m grain.

 */

class GrassCover

{

public:

    GrassCover();

    ~GrassCover();

    void setup();

    // the number of steps used internally

    static const int GRASSCOVERSTEPS = 32000;

    /// set for all the pixels (LIFPixels) the corresponding grass value (in percent: 0-100)

    void setInitialValues(const QVector<float*> &LIFpixels, const int percent);

    /// main function (growth/die-off of grass cover)

    void execute();

    // access

    /// returns 'true' if the module is enabled

    bool enabled() const { return mEnabled; }

    ///

    double effect(grass_grid_type level) const { return mEffect[level]; }

    double cover(const grass_grid_type &data) const  {return mType == Pixel? data : data/double(GRASSCOVERSTEPS-1);  }

    /// main function

    double regenerationInhibition(QPoint &lif_index) const {

        if (mType==Pixel)

            // -1: off, out of project area, 0: off, ready to get grassy again, 1: off (waiting for LIF threshold), >1 on, counting down

            return mGrid.constValueAtIndex(lif_index)>1 ? 1. : 0.;

        // type continuous

        return mEnabled?effect(mGrid.constValueAtIndex(lif_index)) : 0.;

    }

    /// retrieve the grid of current grass cover

    const Grid<grass_grid_type> &grid() { return mGrid; }

private:

    enum GrassAlgorithmType { Invalid, Continuous, Pixel };

    GrassAlgorithmType mType;

    bool mEnabled; ///< is module enabled?

    Expression mGrassPotential; ///< function defining max. grass cover [0..1] as function of the LIF pixel value

    Expression mGrassEffect; ///< equation giving probability of *prohibiting* regeneration as a function of grass level [0..1]

    int mMaxTimeLag; ///< maximum duration (years) from 0 to full cover

    double mEffect[GRASSCOVERSTEPS]; ///< effect lookup table

    Grid<grass_grid_type> mGrid; ///< grid covering state of grass cover (in integer steps)

    int mGrowthRate; ///< max. annual growth rate of herbs and grasses (in 1/256th)

    grass_grid_type mMaxState; ///< potential at lif=1

    RandomCustomPDF mPDF; ///< probability density function defining the life time of grass-pixels

    float mGrassLIFThreshold; ///< if LIF>threshold, then the grass is considered as occupatied by grass

    GrassCoverLayers *mLayers; // visualization

};

/** Helper class manage and visualize data layers.

*/

class GrassCoverLayers: public LayeredGrid<grass_grid_type> {

  public:

    void setGrid(const Grid<grass_grid_type> &grid, const GrassCover *gc) { mGrid = &grid; mGrassCover=gc; }

    double value(const grass_grid_type &data, const int index) const;

    const QVector<LayeredGridBase::LayerElement> &names();

private:

    QVector<LayeredGridBase::LayerElement> mNames;

    const GrassCover *mGrassCover;

};

#endif // GRASSCOVER_H