# Rounding Coordinates

If you want an accuracy of seven digits, should you then round to that value or simply just cut the numbers after that? Example:

51.1936137567 to 51.1936138 or 51.1936137567 to 51.1936137

• Consider what the result will be of each operation. Cutting the numbers will result in a slight bias towards 0 lat 0 lon, while a rounding will not do this. However, this is to be weighted against the additional computational step in your processing. – Mikkel Lydholm Rasmussen Jan 6 '16 at 7:37

## 1 Answer

I guess that is up to you. I would round the number like I do with all numbers with too many digits, a GPS would cut the numbers. So it is a question of accuracy of the origin of your data and the accuracy you want to maintain.

• The accuracy is supposed to be up to 2cm, so seven digits. But the GPS is still giving more digits. So you would just use them all? – Sanny Jan 6 '16 at 7:28
• Well, I don't really see a good reason to loose accuracy. However, there are limitations to the accuracy of the GPS-device aswell, even though more digits are shown. And of course it doesn't make sence to use for example 20 digits. I think it is just important to choose one option and stay with it. And if you can't decide I guess it won't hurt to use 10 digits. Than you don't have to care to much about rounding if you need a accuracy of 7 digits. – Alex Jan 6 '16 at 7:37
• Ok, I think that's a good way to go. Thx – Sanny Jan 6 '16 at 7:44