Alexandre, I believe that true north is actually a constant oriented towards the North Pole, i e 90 degrees north latitude. Also where all meridians converge in the northern hemisphere.
The other North orientations are magnetic north and grid North and these do vary as you suggested. I do need to use a UTM projection but need bearings to be in degrees true north. Thanks Alexandre... Cheers . . . . . Spring Samsung Tab 4 On Apr 2, 2018 4:27 PM, "Alexandre Neto" <[email protected]> wrote: > 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 <[email protected]> > 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 >> >> >> _______________________________________________ >> Qgis-user mailing list >> [email protected] >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > -- > Alexandre Neto > --------------------- > @AlexNetoGeo > http://sigsemgrilhetas.wordpress.com > http://gisunchained.wordpress.com >
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