How Short Can a Location Code Be? Cell Size, Search Distance, and the Code Length a Settlement Actually Needs

Many settlements have no street names, so a delivery address must be built from a grid code spoken, written on an envelope, or sent by phone. This paper computes how long such a code needs to be. A square settlement 4 km on a side is divided by a 20-symbol grid alphabet; each additional pair of characters divides the cell side by 20. One pair of characters leaves a cell 200.0 m across and two pairs leave one of 10.0 m, so at a stated search tolerance of 50 m, 2 pairs, i.e. 4 characters, give a cell 10.0 m across, one of 160000 cells, costing 4.8 s to dictate at 1.2 s per character. The paper derives the general rule — pairs needed grow only with the logarithm of settlement size divided by tolerance — and tabulates it for settlement sides from 1 to 16 km and tolerances from 10 to 200 m, so an operator can choose a code length before printing a single form. SIMULATED, NOT MEASURED.