GEOPOS key member [member …]
Return the positions (longitude,latitude) of all the specified members of the geospatial index represented by the sorted set at key.
Given a sorted set representing a geospatial index, populated using the GEOADD command, it is often useful to obtain back the coordinates of specified members. When the geospatial index is populated via GEOADD the coordinates are converted into a 52 bit geohash, so the coordinates returned may not be exactly the ones used in order to add the elements, but small errors may be introduced.
The command can accept a variable number of arguments so it always returns an array of positions even when a single element is specified.
Array reply, specifically:
The command returns an array where each element is a two elements array
representing longitude and latitude (x,y) of each member name passed as
argument to the command.
Non existing elements are reported as NULL elements of the array.
redis> GEOPOS Sicily Palermo Catania NonExisting
1) 1) "13.36138933897018433" 2) "38.11555639549629859" 2) 1) "15.08726745843887329" 2) "37.50266842333162032" 3) (nil)