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What is the shortest and longest amount of numbers that latitude and longitudinal coordinates may have?

For instance i know that London is 51.5072 0.1275. So the first value is 6 numbers and the second is 4 (or 5 depending on how you look at it).

Evanss
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  • For the "shortest" amount: there is a location at 0.0 0.0, as such, depending on your definitions, zero , one or two numbers. – Mikkel Lydholm Rasmussen Jan 08 '16 at 12:36
  • Real values do not have limits, but there are scale-appropriate boundaries. Latitude is bounded by 90S (-90.0) and 90N (+90.0), but longitude is unbounded (1000W is valid, though it could be represented by smaller values). I'll generally use "12.6" formatting on degrees, which provides precision to ~11cm, but if I know the collection protocol has much less precision, I'll use fewer digits to the right. – Vince Jan 08 '16 at 12:39

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Theoretically the precision is unlimited. You could very well say that 51.5072321685498474643544 0.127556181987987156543154 is a point somewhere in London. However it rarely makes sense to use such a high precision. File formats and tools often have hard-coded limits of precision. If not by the format itself then by the data type used internally. See https://en.wikipedia.org/wiki/Floating_point#IEEE_754:_floating_point_in_modern_computers for an introduction in number representation in computer systems.

Usually you are only interested in a precision up to a certain degree (pun intended!). So first decide how many digits you actually need or utilise, then use one more for safety.

Check Measuring accuracy of latitude and longitude? or the Wikipedia article on https://en.wikipedia.org/wiki/Decimal_degrees for more information and conversions to meters.

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bugmenot123
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