public ShapeFieldCacheDistanceValueSource(SpatialContext ctx, 
     ShapeFieldCacheProvider<IPoint> provider, IPoint from, double multiplier)
 {
     this.ctx = ctx;
     this.from = from;
     this.provider = provider;
     this.multiplier = multiplier;
 }
 public ShapeFieldCacheDistanceValueSource(SpatialContext ctx, ShapeFieldCacheProvider<Point> provider, Point from)
 {
     this.ctx = ctx;
     this.from = from;
     this.provider = provider;
 }
		public ShapeFieldCacheDistanceValueSource(Point from, DistanceCalculator calc, ShapeFieldCacheProvider<Point> provider)
		{
			this.from = from;
			this.provider = provider;
			this.calculator = calc;
		}