Adjusting for Declination 10 Min to Better Land Navigation Part 7

[@TheSaneHatter]

Thanks for ALL of your caution and care, Dave. It was only today that I was watching a video on "Fascinating Horror" about a woman who survived being lost in the Grand Canyon, after being misled by an illegible sign, and thanks to you, I was able to propose how some of your ideas about having a visible marker could have helped her in that situation! Moreover, I have all the respect in the world if you're dyslexic: I'm disabled myself, with Asperger's Syndrome and AD/HD, among other problems. And while dyslexia isn't one of MY symptoms (in point of fact, I'm HYPERlexic, and can read & write most people in circles), I've seen it at my job among more than one of my supervisors, so I'll never turn up my nose at it. Neurodivergence rocks!

[@stevemulholland1532]

Dave I draw the military declination diagram aid into my notepad. I also draw in two other diagrams showing the degrees of arc in a westerly and easterly declination situation. I will avoid discussing Grid North (grid convergence) at this stage of learning. The people I taught really became confused when I introduced Grid Magnetic Angle/convergence. I probably lost most people here already. Suffice it to say grid north is usually 0 to 2 degrees off True North in most of Canada and the USA. It can more in certain areas. Angles always begin at 360/N. I draw a L with true north to the top of the L. The angle to the right baseline line is 90 degrees. If Magnetic North is to the left of True North (westerly) I draw a line from the bottom of TN up along TN roughly offset to the local declination. The diagram is a memory jog. The angle drawn is larger than 90 TN. If I take a map azimuth with either the compass as a protractor or use a protractor I have to add declination to meet up with the larger magnetic angle and needle. It helps to draw an arc from both lines to the end of the bottom base line to illustrate which has the larger arc to baseline. Grid Magnetic angle can be introduced once folks have normal declination down pat. For the average person GMA is not much of a safety issue. Failure to account for the slight difference in True North to Grid North can be a disaster. On a glacier you do not want to be out 1 or 2 degrees. Pulling a sled in Newfoundland in winter and not calculating Grid Magnetic Angle (Grid North to MN) versus normal declination (TN to MN) could mean you would miss your cabin and be in trouble. I probably lost most people. Unless you print a Caltopo Map showing the 3 Norths GMA gets people confused. Grid North and the grid convergence angle is shown on the map's declination diagram. Grid North can be either side of True North. It depends on where you are in the UTM zone. I am not sure if folks are aware that the declination web sites only give you regular declination. Only a map site relays this angle between TN and Grid North. You are then able to calculate the precise GMA (declination). I suspect I have only created more curiousity for the intermediate navigator. Beginners find GMA difficult to grasp.

[@darrinmartin8247]

You rock Dave! Dave is the King

[@williammrdeza9445]

No problem Dave. Thanks for the additional clarification.

[@stevemulholland1532]

Well explained Dave. I enjoy your channel.

[@mrkultra1655]

Thanks Dave. One thing that I think may confuse folks, is that when you turn the dial to the left (counter clockwise) to add, that how are smaller numbers adding to 360 degrees? Remember that when the dial is at 360, it is also at “Zero” degrees.

[@Snorky_88]

I remember learning about this in the army. Totally forgot about it until now.

[@haroldmiller6853]

I fully understand , I work with mentally challenged adults and when that are having a bad day and I’m doing books I get stuff wrote backwards and transposed everything. It happens just shows your human none of us are perfect

[@RatdogDRB]

What I wonder about is the reports of changes in the earth's magnetics (poles). Is that (as of yet) having an effect upon declination adjustments to our compasses?

[@MtMan146]

Understand, Thanks

[@thomasgold-1000]

Hi Dave, please take the time and go back to “Part 4” and check out my comment; there’s a lapse with regard to the 45º-method that could lead to confusion! Great series…

[@davehumpleby3440]

Try this for a memory aid: Grid to Mag, add. Mag to Grid, get rid.

[@DavidCanterbury]

Doesn’t work for Easterly Declination

[@MadDogSurvival]

WAVES… West Add versus East Subtract

[@marksolum1794]

Seems like you should just take the time to set your declination and make them the same.

[@DavidCanterbury]

As stated in the previous video