Application: gvSIG desktop » gvSIG tools: ToolBox

package es.unex.sextante.hydrology.slopeLength;

import java.util.Arrays;

import es.unex.sextante.additionalInfo.AdditionalInfoNumericalValue;

import es.unex.sextante.core.GeoAlgorithm;

import es.unex.sextante.core.AnalysisExtent;

import es.unex.sextante.core.Sextante;

import es.unex.sextante.dataObjects.IRasterLayer;

import es.unex.sextante.exceptions.GeoAlgorithmExecutionException;

import es.unex.sextante.exceptions.RepeatedParameterNameException;

import es.unex.sextante.rasterWrappers.GridCell;

public class SlopeLengthAlgorithm

         extends

            GeoAlgorithm {

   private final static int   m_iOffsetX[] = { 0, 1, 1, 1, 0, -1, -1, -1 };

   private final static int   m_iOffsetY[] = { 1, 1, 0, -1, -1, -1, 0, 1 };

   public static final String DEM          = "DEM";

   public static final String USETHRESHOLD = "USETHRESHOLD";

   public static final String THRESHOLD    = "THRESHOLD";

   public static final String SLOPELENGTH  = "SLOPELENGTH";

   private int                m_iNX, m_iNY;

   private IRasterLayer       m_DEM        = null;

   private IRasterLayer       m_SlopeLength;

   private IRasterLayer       m_Slope;

   private double             m_dThreshold;

   private boolean            m_bUseThreshold;

   @Override

   public boolean processAlgorithm() throws GeoAlgorithmExecutionException {

      int i;

      m_DEM = m_Parameters.getParameterValueAsRasterLayer(DEM);

      m_bUseThreshold = m_Parameters.getParameterValueAsBoolean(USETHRESHOLD);

      m_dThreshold = Math.abs(m_Parameters.getParameterValueAsDouble(THRESHOLD));

      m_SlopeLength = getNewRasterLayer(SLOPELENGTH, Sextante.getText("Slope_length"), IRasterLayer.RASTER_DATA_TYPE_FLOAT);

      m_SlopeLength.assign(0.0);

      final AnalysisExtent extent = m_SlopeLength.getWindowGridExtent();

      m_Slope = getTempRasterLayer(IRasterLayer.RASTER_DATA_TYPE_FLOAT, extent);

      m_DEM.setWindowExtent(extent);

      m_iNX = m_DEM.getNX();

      m_iNY = m_DEM.getNY();

      if (m_bUseThreshold) {

         createSlopeLayer();

      }

      final GridCell[] cells = getSortedArrayOfCells(m_DEM);

      final int iCells = cells.length;

      for (i = iCells - 1; (i > -1) && setProgress(iCells - i, iCells); i--) {

         setLength(cells[i].getX(), cells[i].getY());

      }

      return !m_Task.isCanceled();

   }

   @Override

   public void defineCharacteristics() {

      setName(Sextante.getText("Slope_length"));

      setGroup(Sextante.getText("Indices_and_other_hydrological_parameters"));

      setUserCanDefineAnalysisExtent(true);

      try {

         m_Parameters.addInputRasterLayer(DEM, Sextante.getText("Elevation"), true);

         m_Parameters.addNumericalValue(THRESHOLD, Sextante.getText("Slope_change_threshold"), 0.5,

                  AdditionalInfoNumericalValue.NUMERICAL_VALUE_DOUBLE);

         m_Parameters.addBoolean(USETHRESHOLD, Sextante.getText("Use_threshold"), true);

         addOutputRasterLayer(SLOPELENGTH, Sextante.getText("Slope_length"));

      }

      catch (final RepeatedParameterNameException e) {

         Sextante.addErrorToLog(e);

      }

   }

   private void createSlopeLayer() {

      int x, y;

      for (y = 0; y < m_iNY; y++) {

         for (x = 0; x < m_iNX; x++) {

            m_Slope.setCellValue(x, y, m_DEM.getSlope(x, y));

         }

      }

   }

   private void setLength(final int x,

                          final int y) {

      int i, ix, iy;

      double dSlope, dSlope2;

      double dLength;

      double dValue;

      dValue = m_DEM.getCellValueAsDouble(x, y);

      if (!m_DEM.isNoDataValue(dValue) && ((i = m_DEM.getDirToNextDownslopeCell(x, y)) >= 0)) {

         ix = x + m_iOffsetX[i];

         iy = y + m_iOffsetY[i];

         dValue = m_DEM.getCellValueAsDouble(ix, iy);

         if (!m_DEM.isNoDataValue(dValue)) {

            if (m_bUseThreshold) {

               dSlope = m_Slope.getCellValueAsDouble(x, y);

               dSlope2 = m_Slope.getCellValueAsDouble(ix, iy);

               if (Math.abs(dSlope2) > m_dThreshold * Math.abs(dSlope)) {

                  dLength = m_SlopeLength.getCellValueAsDouble(x, y) + m_DEM.getDistToNeighborInDir(i);

               }

               else {

                  dLength = m_DEM.getDistToNeighborInDir(i);

               }

               if (dLength > m_SlopeLength.getCellValueAsDouble(ix, iy)) {

                  m_SlopeLength.setCellValue(ix, iy, dLength);

               }

            }

            else {

               dLength = m_SlopeLength.getCellValueAsDouble(x, y) + m_DEM.getDistToNeighborInDir(i);

               if (dLength > m_SlopeLength.getCellValueAsDouble(ix, iy)) {

                  m_SlopeLength.setCellValue(ix, iy, dLength);

               }

            }

         }

      }

      else {

         m_SlopeLength.setNoData(x, y);

      }

   }

   public GridCell[] getSortedArrayOfCells(final IRasterLayer layer) {

      int i;

      int iX, iY;

      final int iNX = layer.getNX();

      final int iCells = layer.getNX() * layer.getNY();

      GridCell[] cells;

      GridCell cell;

      cells = new GridCell[iCells];

      for (i = 0; i < iCells; i++) {

         iX = i % iNX;

         iY = i / iNX;

         cell = new GridCell(iX, iY, layer.getCellValueAsDouble(iX, iY));

         cells[i] = cell;

      }

      Arrays.sort(cells);

      return cells;

   }

}