[Qgis-user] True North

[Alexandre Neto]

AFAIK, true bearing differs in time and location because of magnetic
declination. So I don't think there is a such thing as a CRS with true
bearings.

Assuming you are working at regional level, find the magnetic declination
for that region and remove it from your observations. Then draw the azimuth
using the chosen CRS. I think 26910 will work just fine.

If you are at a larger scale, then you may need to use different magnetic
declination values for each observation.

This may help:

https://www.ngdc.noaa.gov/geomag/declination.shtml

Best Regards,

Alexandre Neto

A seg, 2/04/2018, 23:54, Springfield Harrison <stellargps at gmail.com>
escreveu:

> Hello,
>
> I am using CRS 26910, NAD83 / UTM zone 10N, and need to draw lines at
> exact true bearings.  The Advanced Digitizing Tool seems to do this but
> which CRS would I use to ensure that the bearing is True?
>
> Thanks very much . . .
>
>
> Cheers . . . . . Springfield Harrison
>
>
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-- 
Alexandre Neto
---------------------
@AlexNetoGeo
http://sigsemgrilhetas.wordpress.com
http://gisunchained.wordpress.com
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