Help me set my declination to Grid to Magnetic

[corylee4870]

Per Dick Blust, declination should be set at 5 degrees east for “Grid-to-Magnetic Declination.”

This is a MyTopo.com map. The diagram on this map is just a little different than what his show.

Also, 2 different websites show the magnetic declination of Dolores CO to be 9 degrees east.

It almost looks to me like the mytopo.com map is 2 degrees between True North & Grid North and 7 degrees between Grid North & True North. That would make it 9 degrees between True North and Magnetic North.

Any experts here that can verify it is 5 degrees East for Grid-to-Magnetic North on this map? Or is it 7 degrees East?

 

[ramont]

I'm confused why you're confused.

True north, grid north, and magnetic north are three different things.
-True North is a line that points to the the location of the northern point of the earth's rotational axis
-Grid North is a line that parallels the UTM (Universal Transverse Mercator Coordinate System lines)
-Magnetic North is a line that points to the location of the magnetic north of the earth

The map shows that there are 2 degrees difference between True North and Grid North and another 7 degrees difference between Grid North and Magnetic North.

The NOAA web site shows that there are 9 degrees 34 minutes of difference between the True North line and the Magnetic North line.

 

[corylee4870]

I agree that the map shows 2 degrees True to Grid and 7 degrees from Grid to Magnetic.

The Dick Blust article is what confused me. You can see in his first diagram (figure 19) that it says to get the grid-to-magnetic declination you need to subtract true-to-Grid (2) from true-to-magnetic (7). So, per Dick Blust it would be 5 degrees east.

His diagrams are labeled differently than this one I guess.

Thank you for your help. I’m going with 7.


Sent from my iPhone using Tapatalk