isabella232 / geohashi

Go(lang) clone of geohash-int

GeoHashi

Geohash library for Go, optimised for performance. Inspired by geohash-int.

Examples

Encode coordinates:

func Encode() {
	lat, lon := 51.52463, -0.08411

	hash1 := geohashi.EncodeWithPrecision(lat, lon, 10)
	fmt.Printf("%d (%d)\n", hash1, hash1.Precision())

	hash2 := geohashi.EncodeWithPrecision(lat, lon, 20)
	fmt.Printf("%d (%d)\n", hash2, hash2.Precision())
}

Decode hash:

func Decode() {
	hash := geohashi.Hash(90072520759854475)
	area := hash.Decode()
	lat, lon := area.Center()

	fmt.Printf("%.5f,%.5f\n", lat, lon)
	fmt.Println(area.Contains(51.52463, -0.08411))
}

Precision

This library allows you to select the precision of the hash you want to create, up to a maximum of 26 bits.

The following table shows the maximum uncertainty (at the equator) for a given bit-precision:

Bits	Uncertainty
26	±0.35m
25	±0.65m
24	±1.3m
23	±2.6m
22	±5.3m
21	±11m
20	±21m
19	±42m
18	±84m
17	±170m
16	±340m
15	±680m
14	±1400m
13	±2700m
12	±5400m
11	±11000m
10	±22000m
9	±43000m
8	±86000m
7	±170000m
6	±350000m
5	±690000m
4	±1400000m
3	±2800000m
2	±5400000m
1	±10000000m