Originally Posted By: Pete
My GPS puts out degrees, minutes, decimal minutes.
I've got no problem passing that on to a dispatcher. but what words exactly do I say to them ...

"here are my coordinates.
I'm giving you degrees, minutes, and decimal minutes.
do you understand over?"

WILL this conversation make sense to them?
Or do I describe the system some other way??


I explored this kind of thing with some local agencies. My chief concern was which horizontal datum they used.

Funny conversation I had with a medical transport helicopter pilot:

G-A-R: "What datum does your onboard GPS nav system use?"

pilot: "Degrees, minutes, fractions of minutes."

G-A-R: "OK, thanks..." <shakes head>

While land-based people often switch their GPS unit's horizontal datum between NAD27 (or other local datum) and WGS84 to jive with the paper maps they have, aviation and naval assets almost always stick with WGS84. Of course I am quite open to correction on this, I know we have some solid SMEs on the forum.

Regardless, I would always include the horizontal datum when reporting coordinates. If the people on the other end of the line have the knowhow to use that info, great; if they don't then it won't hurt them to hear the info.