Dryopithecus's picture

Locations accurate to the nearest 11 cm or less?

I notice that locations are currently given to six decimal places.

The circumference of the earth being 40 megametres (Wikipedia), one degree of longitude at the equator, or one degree of latitude anywhere, is about 111 km, so 0.000001 degrees is 11 cm or less. Is this degree of accuracy necessary, desirable or achievable?

May I suggest that 4 decimal places would be sufficient, which would fix the location within an 11m square at the equator, or a narrower rectangle at higher latitudes (7m by 11m at 50 degrees N or S, for instance)?