Question 1121

Forty Metres Apart

Two scooters sit 40 metres apart on opposite sides of a street, and your geohash prefix search for one of them never returns the other. Their geohash strings diverge after only three characters. What is happening and what is the standard fix?

A

Geohash strings sort by proximity, so the fix is to scan the keys immediately before and after the target string in lexical order

B

The two records were encoded at different precisions, so normalising both strings to the same character length will make the prefix match succeed

C

They straddle a cell boundary, so one lookup cannot see across it; search the eight adjacent cells too, then rank by true distance

D

The precision is too coarse for a 40 metre gap; adding two more characters to the prefix will bring both scooters into the same cell