/// <summary>
/// Gets or sets a value at the 0 row, 0 column index.
/// </summary>
/// <param name="row">The 0 based vertical row index from the top</param>
/// <param name="column">The 0 based horizontal column index from the left</param>
/// <returns>An object reference to the actual value in the data member.</returns>
public double this[int row, int column]
{
get
{
if (_sourceRaster.IsInRam)
{
return(ToDouble(_sourceRaster.Data[row][column]));
}
if (_rowBuffer[0] == null)
{
_rowBuffer[0] = _sourceRaster.ReadRow(_topRow);
}
if (_rowBuffer[1] == null)
{
_rowBuffer[1] = _sourceRaster.ReadRow(_topRow + 1);
}
if (_rowBuffer[2] == null)
{
_rowBuffer[2] = _sourceRaster.ReadRow(_topRow + 2);
}
int shift = row - _topRow;
if (shift >= 0 && shift < 3)
{
// the value is in a row buffer
return(ToDouble(_rowBuffer[row - _topRow][column]));
}
// the value was not found in the buffer. If the value is below the row buffer, load the new row as the bottom row.
if (shift == 3)
{
_rowBuffer[0] = _rowBuffer[1];
_rowBuffer[1] = _rowBuffer[2];
_rowBuffer[2] = _sourceRaster.ReadRow(row);
return(ToDouble(_rowBuffer[2][column]));
}
if (shift == 4)
{
_rowBuffer[0] = _rowBuffer[2];
_rowBuffer[1] = _sourceRaster.ReadRow(row - 1);
_rowBuffer[2] = _sourceRaster.ReadRow(row);
return(ToDouble(_rowBuffer[2][column]));
}
if (shift > 4)
{
_rowBuffer[0] = _sourceRaster.ReadRow(row - 2);
_rowBuffer[1] = _sourceRaster.ReadRow(row - 1);
_rowBuffer[2] = _sourceRaster.ReadRow(row);
return(ToDouble(_rowBuffer[2][column]));
}
if (shift == -1)
{
_rowBuffer[0] = _sourceRaster.ReadRow(row);
_rowBuffer[1] = _rowBuffer[0];
_rowBuffer[2] = _rowBuffer[1];
return(ToDouble(_rowBuffer[0][column]));
}
if (shift == -2)
{
_rowBuffer[0] = _sourceRaster.ReadRow(row);
_rowBuffer[1] = _sourceRaster.ReadRow(row + 1);
_rowBuffer[2] = _rowBuffer[0];
return(ToDouble(_rowBuffer[0][column]));
}
if (shift < -2)
{
_rowBuffer[0] = _sourceRaster.ReadRow(row);
_rowBuffer[1] = _sourceRaster.ReadRow(row + 1);
_rowBuffer[2] = _sourceRaster.ReadRow(row + 2);
return(ToDouble(_rowBuffer[0][column]));
}
// this should never happen
throw new ApplicationException(DataStrings.IndexingErrorIn_S.Replace("%S", "Raster.Value[" + row + ", " + column + "]"));
}
set
{
_updated = true;
if (!_sourceRaster.IsInRam)
{
return;
}
T test = (T)Convert.ChangeType(value, typeof(T));
if (test.CompareTo(Global.MaximumValue <T>()) > 0)
{
_sourceRaster.Data[row][column] = Global.MaximumValue <T>();
}
else if (test.CompareTo(Global.MinimumValue <T>()) < 0)
{
_sourceRaster.Data[row][column] = Global.MinimumValue <T>();
}
else
{
// This is slow so only do this when we have to.
_sourceRaster.Data[row][column] = test;
}
}
}