// https://github.com/yinqiwen/ardb/blob/master/doc/spatial-index.md
// http://gis.stackexchange.com/questions/18330/would-it-be-possible-to-use-geohash-for-proximity-searches
func (_ Test) GeoHashInt() {
lat := 56.162939
long := 10.203921
hash := geoInt.EncodeInt(lat, long, 52) // 0.5971 meters
hash = geoInt.EncodeInt(lat, long, 18) // 78 km
e.InfoLog.Println(hash)
neighbours := geoInt.EncodeNeighborsInt(hash, 18)
neighbours = append(neighbours, hash)
sortUint64.Asc(neighbours)
e.InfoLog.Println(neighbours)
}
func getQueryRangesFromBitDepth(lat, lon float64, radiusBitDepth, bitDepth uint8) ([]geoRange, error) {
bitDiff := bitDepth - radiusBitDepth
if bitDiff < 0 {
return []geoRange{}, fmt.Errorf("bitDepth must be high enough to calculate range within radius")
}
hash := geohash.EncodeInt(lat, lon, radiusBitDepth)
neighbors := geohash.EncodeNeighborsInt(hash, radiusBitDepth)
neighbors = append(neighbors, hash)
sort.Sort(uint64Slice(neighbors))
if radiusBitDepth <= 4 {
neighbors = uniqueInSlice(neighbors)
}
ranges := []geoRange{}
for i := 0; i < len(neighbors); i++ {
lowerRange := float64(neighbors[i])
upperRange := lowerRange + 1
for len(neighbors) > i+1 && float64(neighbors[i+1]) == upperRange {
neighbors = neighbors[1:]
upperRange = float64(neighbors[i] + 1)
}
ranges = append(ranges, geoRange{Lower: lowerRange, Upper: upperRange})
}
for key := range ranges {
ranges[key].Lower = leftShift(ranges[key].Lower, bitDiff)
ranges[key].Upper = leftShift(ranges[key].Upper, bitDiff)
}
return ranges, nil
}