public override Double Get(Double x, Double y)
{
if (!this.cache2D.IsValid || this.cache2D.X != x || this.cache2D.Y != y)
{
this.cache2D.X = x;
this.cache2D.Y = y;
this.cache2D.IsValid = true;
this.cache2D.Value = this.Source.Get(x, y);
}
return this.cache2D.Value;
}