Question About Datum

[+Velleluvr]

I came across a cache (im using this co-ordinate as only an example), it had extra digits. What do they mean ?

 

N 44° 10.1545 W 077° 35.9243

 

For instance the 5 and the 3 were extra. I ignored them and went only by the 3 digits after the decimal, but where is there a fourth number? What does it mean and have you seen this before?

 

Thanks

[rynd]

It's just a higher resolution coordinate. Just Round off.

 

 

Edited to add: I think.

Edited March 29, 2006 by rynd

[+headybrew]

I came across a cache (im using this co-ordinate as only an example), it had extra digits. What do they mean ?

 

N 44° 10.1545 W 077° 35.9243

 

For instance the 5 and the 3 were extra. I ignored them and went only by the 3 digits after the decimal, but where is there a fourth number? What does it mean and have you seen this before?

 

Thanks

 

Everything after the decimal point is just a fraction of a minute. By the time you get to 4 decimal places, you are beyond the accuracy of your GPSr anyway.

 

Perhaps their GPSr reports the coords to that many decimal places, so they typed them in. That's all. It's likley that they are useless because the GPS accuracy is not good enough to know if they really are a 5 and a 3, or something else really.

 

I wouldn't worry about it.

[+tozainamboku]

BTW, the title of the thread is wrong. You had a question about coordinate format. Usually you will see degrees and decimal minutes with only three digits after the decimal point. The coordinates you post go to a forth decimal place. Datum has nothing to do with the number of decimal places or the format of the coordinates. It is even independent of whether the coordinates are in latitude/longitude or UTM. A datum is a mathematical model of the shape of the earth, usually tied to reference points that are surveyed on the earth. Depending on the shape of the earth the latitude and longitude of a given point may change.