code: function (points, sqTolerance) {
  		var reducedPoints = [points[0]];
  
  		for (var i = 1, prev = 0, len = points.length; i < len; i++) {
  			if (this._sqDist(points[i], points[prev]) > sqTolerance) {
  				reducedPoints.push(points[i]);
  				prev = i;
  			}
  		}
  		if (prev < len - 1) {
  			reducedPoints.push(points[len - 1]);
  		}
  		return reducedPoints;
  	}
docs: reduce points that are too close to each other to a single point