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North arrows showing both grid and magnetic north

December 18 2008 | 1 comment
Categories: Map Elements

I routinely produce maps that are used in the course of fieldwork. Is there any way to generate a north arrow (similar to what's on a USGS 7.5 min quad or military map) that indicates the deviation between grid north and magnetic north?

Mapping Center Answer:

You can either use PLTS for this, or you can compute the amount of magentic declination for your map's location and use that value to rotate a north arrow yourself. Here is a link to the NOAA magentic declination estimator:

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

 

Magnetic Declination posted by Chris Pratt on Jan 29 2009 10:13PM
You can download the "Digital Cartographic Standard for Geologic Map Symbolization" (FGDC-STD-013-2006) from the USGS. You have the option of downloading postscript versions of all the symbology. One of the sections has all the declinations used in the US. You can use these graphics to make your own styles or just cut and paste into your layout when needed. Cut and paste works fine for me (with a tiny bit of tweeking).
Also, ESRI is currently working on 800+ (line & point) styles. There is no definitive time for the release. But it should be cool when it is out.

Peace on the journey.

Chris

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