private ElevationCell GetCell(double x, double y, bool isCreateIfMissing)
{
int ix = 0;
if (_numCellX > 1)
{
ix = (int)((x - _extent.MinX) / _cellSizeX);
ix = MathUtil.Clamp(ix, 0, _numCellX - 1);
}
int iy = 0;
if (_numCellY > 1)
{
iy = (int)((y - _extent.MinY) / _cellSizeY);
iy = MathUtil.Clamp(iy, 0, _numCellY - 1);
}
var cell = _cells[iy][ix];
if (isCreateIfMissing && cell == null)
{
cell = new ElevationCell();
_cells[iy][ix] = cell;
}
return(cell);
}
/// <summary>
/// Creates a new elevation model covering an extent by a grid of given dimensions.
/// </summary>
/// <param name="extent">The XY extent to cover</param>
/// <param name="numCellX">The number of grid cells in the X dimension</param>
/// <param name="numCellY">The number of grid cells in the Y dimension</param>
public ElevationModel(Envelope extent, int numCellX, int numCellY)
{
_extent = extent;
_numCellX = numCellX;
_numCellY = numCellY;
_cellSizeX = extent.Width / numCellX;
_cellSizeY = extent.Height / numCellY;
if (_cellSizeX <= 0.0)
{
_numCellX = 1;
}
if (_cellSizeY <= 0.0)
{
_numCellY = 1;
}
_cells = new ElevationCell[numCellY][];
for (int i = 0; i < numCellY; i++)
{
_cells[i] = new ElevationCell[numCellX];
}
}
