Geohash: Difference between revisions

* [[wp:Geohash|Wikipedia article - Geohash]].

 

 

=={{header|Factor}}==

Factor comes with the <code>geohash</code> vocabulary. See the implementation [https://docs.factorcode.org/content/vocab-geohash.html here].

{{works with|Factor|0.99 2020-03-02}}

 

: encode-geohash ( latitude longitude precision -- str )

! Decoding

"u4pruydqqvj" dup geohash>

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<pre>

 

=={{header|F_Sharp|F#}}==

// Create a geoHash String. Nigel Galloway: June 26th., 2020

let fG n g=Seq.unfold(fun(α,β)->let τ=(α+β)/2.0 in Some(if τ>g then (0,(α,τ)) else (1,(τ,b)))) n

let geoHash n g z=let N="0123456789bcdefghjkmnpqrstuvwxyz" in [|for τ in fN n g z do yield N.[fI τ]|] |> System.String

printfn "%s\n%s\n%s" (geoHash 51.433718 -0.214126 2) (geoHash 51.433718 -0.214126 9) (geoHash 57.64911 10.40744 11)

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<pre>

=={{header|Go}}==

{{trans|Swift}}

 

import (

fmt.Printf("geohash for %v, precision %-2d = %s\n", loc, precs[i], geohash)

}

 

{{out}}

geohash for [51.433718, -0.214126], precision 9 = gcpue5hp4

geohash for [57.649110, 10.407440], precision 11 = u4pruydqqvj

</pre>

 

=={{header|Julia}}==

{{trans|Python}}

const bool2ch = Dict(string(i-1, base=2, pad=5) => ch for (i, ch) in enumerate(ch32))

const ch2bool = Dict(v => k for (k, v) in bool2ch)

println("decoded = ", decoder(encoded))

end

<pre>

encoder(lat=51.433718, lng=-0.214126, pre=2) = gc

decoded = [[57.64911, 57.64911000000001], [10.407439999999998, 10.407440000000008]]

</pre>

 

=={{header|Perl}}==

{{trans|Raku}}

use warnings;

use feature 'say';

map { sprintf("%.@{[max(3,$precision-3)]}f", ( -($$_[0] + $$_[1]) / 2)) .

' ± ' . sprintf('%.3e', (abs($$_[0] - $$_[1]) / 2))

{{out}}

<pre>51.433718, -0.214126, 2 (Ireland, most of England and Wales, small part of Scotland):

 

=={{header|Phix}}==

{{out}}

<pre>

</pre>

Not surprisingly, given the area it covers, "gc" is not even accurate to one significant digit, but a precision of 9 is accurate to 5 or 6 significant decimal digits, 11 to 6 or 7 digits, and 22 exceeds the natural 10 sig digs of %v. Note that 32-bit gives a last character of 'q' for the precision 22 test, for obvious reasons. The above results are from using the 64-bit interpreter.

 

=={{header|Python}}==

bool2ch = {f"{i:05b}": ch for i, ch in enumerate(ch32)}

ch2bool = {v : k for k, v in bool2ch.items()}

([57.64911, 10.40744] , 22)]:

print("encoder(lat=%f, lng=%f, pre=%i) = %r"

 

{{out}}

encoder(lat=57.649110, lng=10.407440, pre=22) = 'u4pruydqqvj8pr9yc27rjr'</pre>

 

 

=={{header|Raku}}==

===Module based===

Reference: Used [https://www.movable-type.co.uk/scripts/geohash.html this] for verification.

 

use Geo::Hash;

# Village Raku is a development committee in north-western Nepal

# https://goo.gl/maps/33s7k2h3UrHCg8Tb6

{{out}}

<pre>gc

to specify an odd precision so the error interval ends up the same for both latitude and longitude.

 

 

sub geo-encode ( Rat(Real) $latitude, Rat(Real) $longitude, Int $precision = 9 ) {

say 'geo-decoded: ', geo-decode($enc).map( {-.sum/2 ~ ' ± ' ~

(abs(.[0]-.[1])/2).Num.fmt('%.3e')} ).join(', ') ~ "\n";

<pre>51.433718, -0.214126, 2:

geo-encoded: gc

geo-encoded: tv1ypk4

geo-decoded: 29.202347 ± 6.866e-04, 81.532974 ± 6.866e-04

</pre>

 

=={{header|Swift}}==

 

 

extension String {

print ("Geohash for: \(coordinate2.toString()), precision = 11 : \(encodeGeohash(for: coordinate, withPrecision: 11))")

 

 

{{out}}

Geohash for: 57.64911 N, 10.40744 E, precision = 11 : u4pruydqqvj

</pre>

 

=={{header|Wren}}==

{{trans|Swift}}

{{libheader|Wren-fmt}}

 

var gBase32 = "0123456789bcdefghjkmnpqrstuvwxyz"

var loc = "[%(Fmt.f(9, d[0][0], 6)), %(Fmt.f(9, d[0][1], 6))]"

System.print("geohash for %(loc), precision %(Fmt.d(-2, d[1])) = %(geohash)")

 

{{out}}