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jezza79

gps datum problem

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hello all

i am not sure how to change coordinates from degree minute seconds to a more familiar style that i use.

 

normally it is written like this eg. S27 31.145 E153 28.775 and that is how my gps allows it but it is quite often written like this 27*31'14" 153* 28'77"

 

how do you convert these?

 

thanks

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The first coordinate is in hddd° mm.mmm' format. The second one in hddd° mm' ss".

in which:

h = hemisphere (N/S or E/W). Sometimes the h is left out and a minus sign (-) is used for South and/or West.

d = degrees

m = minutes

s = seconds

 

There are a lot of apps, programs and websites which can convert this for you.

All stand-alone outdoor GPS receivers can do it natively. Just go to Settings --> position format (or something like that) to enter coordinates in another format.

 

If you want to convert it manually:

From hddd° mm' ss" to hddd° mm.mmm':   .mmm = ss/60.

From hddd° mm.mmm' to hddd° mm' ss":   ss = .mmm*60.

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2 hours ago, StefandD said:

If you want to convert it manually:

 From hddd° mm' ss" to hddd° mm.mmm':   .mmm = ss/60.

From hddd° mm.mmm' to hddd° mm' ss":   ss = .mmm*60.

The important thing to remember is that degrees, minutes, and seconds work exactly the same way that hours, minutes, and seconds do.

 

There are 60 seconds in a minute.

There are 60 minutes in an hour, and 60 minutes in a degree.

 

So the conversion from seconds to fractions of a minute (or vice versa) works the same with coordinates as it does with time.

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A quick side note to the OP: what you are referencing is coordinate format, not datum. The datum is effectively the mathematical model of the shape of the earth, and the same coordinates can reference different spots entirely even when presented in the same format if they are using different underlying datums. For geocaching, we use the WGS84 datum.

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Thanks for the quick response and the info, I should be able to translate it now 

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Posted (edited)
On 4/29/2019 at 4:19 AM, jezza79 said:

normally it is written like this eg. S27 31.145 E153 28.775 and that is how my gps allows it but it is quite often written like this 27*31'14" 153* 28'77"

 

One of thing to note here.   The first set of coordinates are in Degrees Decimal Minutes format and include the hemisphere designation  (S and E) while the second set of coordinates are in Degrees Minutes Second and do not include the hemisphere.   When the hemisphere character (N, S, E, W)  is omitted,  the degrees portion of the coordinates may be a positive or negative number to indicate the hemisphere.  A positive degree value for the latitude will indicate that it is North of the equator while a negative value will indicate that it is South.  The same applies for the longitude.  Positive values indicate that the coordinate is east of the Greenwich mean line and a negative value indicates that it is west.   In your example,  the first set of coordinates would indicate a location south of the equator, while the second set of coordinates would indicate a location *North* of the equator.

Edited by NYPaddleCacher

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