func GetFence(label string, zoom int) (fence GeoFence, err error) {
	switch label {
	case RtreeFence:
		fence = NewRfence()
	default:
		err = fmt.Errorf("Bad fence type: %s", label)
	}
	return
}
// label is a string from FenceLabels
// Zoom only applies to q-based fences
label is a string from FenceLabels
Zoom only applies to q-based fences
// label is a string from FenceLabels // Zoom only applies to q - based fences
func GetFence(label string, zoom int) (fence GeoFence, err error) {
	switch label {
	case RtreeFence:
		fence = NewRfence()
	default:
		err = fmt.Errorf("Bad fence type: %s", label)
	}
	return
}
func GetFence ( label string , zoom int ) ( fence GeoFence , err error ) { switch label { case RtreeFence : fence = NewRfence ( ) default : err = fmt . Errorf ( " " , label ) } return }
label is a string from FenceLabels
Zoom only applies to q-based fences
label is a string from FenceLabels Zoom only applies to q - based fences