True or Magnetic North?

[+stedmanrecon]

I know it can really be a preference, but in your opinion, which is a better setting to use on GPS for geocaching? True North or Magnetic North? Why?

[+cwgrizz]

I know it can really be a preference, but in your opinion, which is a better setting to use on GPS for geocaching? True North or Magnetic North? Why?

 

I had to look at my GPSr to see. I use True North because to the best of my knowledge that is what the default was on the GPSr (I don't remember ever changing it. Ha!) and it has worked fine for me in the field. Really, in the long run, I think unless you are solving a puzzle in the field with one reference or the other required, it really doesn't make that much difference.

[+The A-Team]

I know it can really be a preference...

It isn't really a preference; it depends on what you're doing. Really, the only time it will come into play is if you're doing a projection or something else that requires following a compass bearing. In many puzzles and multis, they'll use true north, so it'll probably be easiest to leave your unit on that setting. Most puzzles and multis will tell you which reference to use, but if it doesn't, you can probably safely assume it's true north.

[+Gitchee-Gummee]

As the A-Team says....

 

Magnetic north shifts (slowly, but continually). Generally the only time one needs to be concerned about it is using printed maps in conjunction with a magnetic compass. One needs to calculate from the map print date to current date and adjust that shift variable (declination) accordingly.

 

Without taking the magnetic declination into account, a LONG (miles, actually) azimuth could be substantially off. A short one, not usually a problem, even if the original projection is years old.

 

Other factors enter into the picture too, but the closer to the equator you are, the less pronounced the difference is. Texas is pretty much considered rather south.

 

EDIT to add: Knowing this even... we stick with the pre-selected setting on the GPSr.

Edited July 9, 2013 by Gitchee-Gummee

[+Markwell]

http://markwell.us/geofaq.htm#truemag

[+dprovan]

True north. Magnetic north only comes up when someone's making a puzzle cache or a multicache a little more complicated. And even then I just use the approximate declination for my area and do the math in my head rather than changing the GPSr setting.

[+stedmanrecon]

Ah! Okay, thank you everyone that responded. After reading these, it make complete sense and reallly seemed like a dumb question lol. I was a whiz at land nav in the Army (got out a few years ago), but just didn't know if cachers usually made their own choice about which to use. I couldn't figure out why magnetic would really come into play with GPSrs, so figured I would ask what folks use that setting for with a device.

 

Again, thanks everyone.