count-index.go
func (countIndex *CountIndex) Range(topLeft Point, bottomRight Point) []Point {
	counters := countIndex.index.Range(topLeft, bottomRight)

	points := make([]Point, 0)

	for _, c := range counters {
		if c.(counter).Point() != nil {
			points = append(points, c.(counter).Point())
		}
	}

	return points
}
func (countIndex *CountIndex) Range(topLeft Point, bottomRight Point) []Point {
	counters := countIndex.index.Range(topLeft, bottomRight)

	points := make([]Point, 0)

	for _, c := range counters {
		if c.(counter).Point() != nil {
			points = append(points, c.(counter).Point())
		}
	}

	return points
}
// Range returns the counters within some lat, lng range.