GPS Coordinate Formats

[Festus Hagen]

This thread was prompted by other recent discussions regarding meeting protocols and the like. I admit that this topic may possibly interest only me, but on the off chance someone else is into it, here goes:

I can't speak for all GPS units but my Garmin likes to take coords in Deg Min Sec. On google maps, if you right click a spot on a map and select "what's here?" you get decimal coords. Don't that just suck?

I posted that nifty converter, but what-to-do if you're out in the woods with no interwebz and you (or someone else) brought the wrong format for your GPS?

Let's think this over. Mike posted some coords for the Finger Lakes trip, 42.491359, -76.791015 , say you're stuck with those but your GPS wants Deg Min Sec? BTW the converter provides 42° 29' 28.8924", -76° 47' 27.654"

Those numbers simply refer to degrees, with decimals. Most folks know that there are 360 degrees in a circle. What Deg Min Sec does, is further divide Degrees. There are 60 Minutes in a Degree, and 60 Seconds in a Minute. A lot like a clock, which makes this sort-of easy to remembrer.

Take 42.491359. We're going to leave 42 degrees alone. We know that .49 is a little less than 1/2, right? So we'd expect that in Minutes, it should be a little less than 30 (as there are 60 minutes in an degree) .491359 x 60=29.48154 Makes sense? We're halfway there, 29 is Minutes. We still have a decimal to deal with tho, so being that there are 60 seconds in a minute, let's multiply .48154 x 60 which gives 28.8924... which is seconds. According to the online converter, we have a winner!

This works the same for latitude and longitude. If you can remember that the decimal after Degrees needs to be multiplied by 60 to get minutes, and the decimal after minutes in the result of THAT calculation needs to be multiplied by 60 to reach seconds (which will almost always have a decimal remainder, which your GPS should be able to handle), you can calculate this yourself.

[MikeM]

Neat, I get lazy about coordinates because my GPS will take multiple formats, and I take for granted that other people's units will as well.

-Mike