Mag North shifting 40 miles per year

[platoonDaddy]

Dang, this certainly means you need updated maps for magnetic declination. Holy shit 40 miles is a shit load of shifting.

http://www.sun-sentinel.com/news/loc...,2819271.story

EDIT: forgot to add this gives new meaning to "LBS" for sure you will be "loss bigger than shit!"

[Nightvisionary]

What a relief. That explains why my land nav skills are so bad.

[platoonDaddy]

What a relief. That explains why my land nav skills are so bad.

LOL, that is GREAT!

For sure we would miss all the points.

[Zhurdan]

If I did my math right, and it's quite possible I didn't so if someone wants to check it, please do.

40 feet lateral from north makes it 5456 miles rather than the 5400 miles from equator to north pole. I think that works out to about 0.01 degree angle change from equator to where the new magnetic north would be pointing you. That amounts to about 56 feet per 100 miles.

Somebody check that. It doesn't sound right and I've been out of school for waaaay to damn long.

[Tortuga]

Too late in the evening for me to do the math, but here's NOAA's declination/Mag Var calculator:

http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

It'll even account for date if you you want to trend it.

[Rmplstlskn]

It's all those darn people in CHINA tipping over the crust of the earth with all that population and raw materials stockpiling...



Rmpl

[Tortuga]

It's all those darn people in CHINA tipping over the crust of the earth with all that population and raw materials stockpiling...

Awesome!
Mind if I use that during my LandNav lesson this class?

[platoonDaddy]

Too late in the evening for me to do the math, but here's NOAA's declination/Mag Var calculator:

http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

It'll even account for date if you you want to trend it.

Great site, thanks for the link.

[PappyM3]

That NOAA calculator is really cool; I had to share it with my friends. I wonder if there's a way to make an app that uses your GPS location and communicates with that jsp to give you an accurate declination on the go?

[USMC_0317_SS]

I have been using the same MIM's for 6 years now along with a standard Lensatic Compass. I have set up several new Land Navigation courses spanning fron 1.5 to 28 kilometers (that I personally run before allowing my students to) and I have not noticed any shift in declination. Like I said same maps for years with the same GM angle.
It must not be far enough to deviate from the desired course to matter. Even a Lensatic Compas that is +/- 3* is still considered good.

Respectfully,
USMC_0317_SS