diff options
Diffstat (limited to 'iredis/data/commands/geohash.md')
-rw-r--r-- | iredis/data/commands/geohash.md | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/iredis/data/commands/geohash.md b/iredis/data/commands/geohash.md new file mode 100644 index 0000000..f091912 --- /dev/null +++ b/iredis/data/commands/geohash.md @@ -0,0 +1,39 @@ +Return valid [Geohash](https://en.wikipedia.org/wiki/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](https://en.wikipedia.org/wiki/Geohash) and +compatible with the [geohash.org](http://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](http://geohash.org/sqdtr74hyu0). +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. + +@return + +@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. + +@examples + +```cli +GEOADD Sicily 13.361389 38.115556 "Palermo" 15.087269 37.502669 "Catania" +GEOHASH Sicily Palermo Catania +``` |