geo-index.go
func (geoIndex *geoIndex) AddEntryAt(point Point) interface{} {
	square := cellOf(point, geoIndex.resolution)

	if _, ok := geoIndex.index[square]; !ok {
		geoIndex.index[square] = geoIndex.newEntry()
	}

	return geoIndex.index[square]
}
func (geoIndex *geoIndex) AddEntryAt(point Point) interface{} {
	square := cellOf(point, geoIndex.resolution)

	if _, ok := geoIndex.index[square]; !ok {
		geoIndex.index[square] = geoIndex.newEntry()
	}

	return geoIndex.index[square]
}
// AddEntryAt adds an entry if missing, returns the entry at specific position.