redis geohash命令

GEOHASH key member [member …]

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Return valid Geohash strings representing the position of one or more elements in a sorted set value representing a geospatial index (where elements were added using GEOADD).

Normally Redis represents positions of elements using a variation of the Geohash
technique where positions are encoded using 52 bit integers. The encoding is
also different compared to the standard because the initial min and max
coordinates used during the encoding and decoding process are different. This
command however returns a standard Geohash in the form of a string as
described in the Wikipedia article and compatible with the geohash.org web site.

*Geohash string properties

The command returns 11 characters Geohash strings, so no precision is loss
compared to the Redis internal 52 bit representation. The returned Geohashes
have the following properties:

  1. They can be shortened removing characters from the right. It will lose precision but will still point to the same area.
  2. It is possible to use them in geohash.org URLs such as http://geohash.org/<geohash-string>. This is an example of such URL.
  3. Strings with a similar prefix are nearby, but the contrary is not true, it is possible that strings with different prefixes are nearby too.

*返回值

Array reply, specifically:

The command returns an array where each element is the Geohash corresponding to
each member name passed as argument to the command.

*例子

redis>  GEOADD Sicily 13.361389 38.115556 “Palermo” 15.087269 37.502669 “Catania”

(integer) 2

redis>  GEOHASH Sicily Palermo Catania

1) "sqc8b49rny0"
2) "sqdtr74hyu0"
redis>