mirror of https://github.com/tidwall/tile38.git
215 lines
4.9 KiB
Markdown
215 lines
4.9 KiB
Markdown
# geohash
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Go [geohash](https://en.wikipedia.org/wiki/Geohash) library offering encoding
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and decoding for string and integer geohashes.
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[](http://godoc.org/github.com/mmcloughlin/geohash)
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[](https://travis-ci.org/mmcloughlin/geohash)
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[](https://coveralls.io/r/mmcloughlin/geohash)
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[](https://goreportcard.com/report/github.com/mmcloughlin/geohash)
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## Install
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Fetch the package with
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```
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go get github.com/mmcloughlin/geohash
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```
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And import it into your programs with
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```go
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import "github.com/mmcloughlin/geohash"
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```
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## Usage
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#### func Decode
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```go
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func Decode(hash string) (lat, lng float64)
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```
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Decode the string geohash to a (lat, lng) point.
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#### func DecodeCenter
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```go
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func DecodeCenter(hash string) (lat, lng float64)
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```
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DecodeCenter decodes the string geohash to the central point of the bounding
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box.
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#### func DecodeInt
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```go
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func DecodeInt(hash uint64) (lat, lng float64)
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```
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DecodeInt decodes the provided 64-bit integer geohash to a (lat, lng) point.
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#### func DecodeIntWithPrecision
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```go
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func DecodeIntWithPrecision(hash uint64, bits uint) (lat, lng float64)
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```
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DecodeIntWithPrecision decodes the provided integer geohash with bits of
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precision to a (lat, lng) point.
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#### func Encode
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```go
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func Encode(lat, lng float64) string
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```
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Encode the point (lat, lng) as a string geohash with the standard 12 characters
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of precision.
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#### func EncodeInt
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```go
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func EncodeInt(lat, lng float64) uint64
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```
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EncodeInt encodes the point (lat, lng) to a 64-bit integer geohash.
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#### func EncodeIntWithPrecision
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```go
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func EncodeIntWithPrecision(lat, lng float64, bits uint) uint64
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```
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EncodeIntWithPrecision encodes the point (lat, lng) to an integer with the
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specified number of bits.
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#### func EncodeWithPrecision
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```go
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func EncodeWithPrecision(lat, lng float64, chars uint) string
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```
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EncodeWithPrecision encodes the point (lat, lng) as a string geohash with the
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specified number of characters of precision (max 12).
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#### func Neighbor
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```go
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func Neighbor(hash string, direction Direction) string
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```
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Neighbor returns a geohash string that corresponds to the provided geohash's
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neighbor in the provided direction
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#### func NeighborInt
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```go
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func NeighborInt(hash uint64, direction Direction) uint64
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```
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NeighborInt returns a uint64 that corresponds to the provided hash's neighbor in
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the provided direction at 64-bit precision.
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#### func NeighborIntWithPrecision
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```go
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func NeighborIntWithPrecision(hash uint64, bits uint, direction Direction) uint64
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```
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NeighborIntWithPrecision returns a uint64s that corresponds to the provided
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hash's neighbor in the provided direction at the given precision.
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#### func Neighbors
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```go
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func Neighbors(hash string) []string
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```
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Neighbors returns a slice of geohash strings that correspond to the provided
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geohash's neighbors.
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#### func NeighborsInt
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```go
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func NeighborsInt(hash uint64) []uint64
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```
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NeighborsInt returns a slice of uint64s that correspond to the provided hash's
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neighbors at 64-bit precision.
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#### func NeighborsIntWithPrecision
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```go
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func NeighborsIntWithPrecision(hash uint64, bits uint) []uint64
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```
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NeighborsIntWithPrecision returns a slice of uint64s that correspond to the
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provided hash's neighbors at the given precision.
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#### type Box
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```go
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type Box struct {
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MinLat float64
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MaxLat float64
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MinLng float64
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MaxLng float64
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}
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```
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Box represents a rectangle in latitude/longitude space.
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#### func BoundingBox
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```go
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func BoundingBox(hash string) Box
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```
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BoundingBox returns the region encoded by the given string geohash.
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#### func BoundingBoxInt
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```go
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func BoundingBoxInt(hash uint64) Box
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```
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BoundingBoxInt returns the region encoded by the given 64-bit integer geohash.
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#### func BoundingBoxIntWithPrecision
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```go
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func BoundingBoxIntWithPrecision(hash uint64, bits uint) Box
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```
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BoundingBoxIntWithPrecision returns the region encoded by the integer geohash
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with the specified precision.
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#### func (Box) Center
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```go
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func (b Box) Center() (lat, lng float64)
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```
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Center returns the center of the box.
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#### func (Box) Contains
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```go
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func (b Box) Contains(lat, lng float64) bool
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```
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Contains decides whether (lat, lng) is contained in the box. The containment
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test is inclusive of the edges and corners.
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#### func (Box) Round
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```go
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func (b Box) Round() (lat, lng float64)
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```
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Round returns a point inside the box, making an effort to round to minimal
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precision.
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#### type Direction
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```go
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type Direction int
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```
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Direction represents directions in the latitute/longitude space.
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```go
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const (
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North Direction = iota
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NorthEast
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East
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SouthEast
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South
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SouthWest
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West
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NorthWest
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)
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```
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Cardinal and intercardinal directions
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