/// <summary>
/// Bilinearly interpolate between four values.
/// </summary>
/// <param name="ul">The upper left value.</param>
/// <param name="ur">The upper right value.</param>
/// <param name="ll">The lower left value.</param>
/// <param name="lr">The lower right value.</param>
/// <param name="x">The horizontal interpolation factor.</param>
/// <param name="y">The vertical interpolation factor.</param>
/// <returns>The interpolated value between all four points by the interpolation factors.</returns>
public static double BilinerInterpolate(double ul, double ur, double ll, double lr, double x,
double y)
{
var u = MapUtil.Interpolate(ul, ur, x);
var l = MapUtil.Interpolate(ll, lr, x);
return(MapUtil.Interpolate(u, l, y));
}
/// <summary>
/// Get the ocean bias for a cell.
/// </summary>
/// <param name="ca">The cell address</param>
/// <returns></returns>
public float OceanBiasAt(CellAddress ca)
{
var pX = (ca.X / _cellsPerPoint) * _cellsPerPoint;
var pY = (ca.Y / _cellsPerPoint) * _cellsPerPoint;
var ul = GetBiasPoint(pX, pY).PercentOcean;
var ur = GetBiasPoint(pX + _cellsPerPoint, pY).PercentOcean;
var ll = GetBiasPoint(pX, pY + _cellsPerPoint).PercentOcean;
var lr = GetBiasPoint(pX + _cellsPerPoint, pY + _cellsPerPoint).PercentOcean;
var xPerc = (ca.X - pX) / (float)_cellsPerPoint;
var yPerc = (ca.Y - pY) / (float)_cellsPerPoint;
return((float)MapUtil.BilinerInterpolate(ul, ur, ll, lr, xPerc, yPerc));
}