Ah sorry, I got lost in translation. You are right, I was talking about the magnetic north, not the geodetic one.
Meanwhile, remembering that all UTM are Transverse Mercator, I don't think there's a CRS that will solve you question. I think you need to use some formula to convert the grid north measures to true north according to the CRS, and the latitude and longitude of the place. Alexandre A ter, 3/04/2018, 09:25, Springfield Harrison <stellar...@gmail.com> escreveu: > 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" <senhor.n...@gmail.com> 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 <stellar...@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 >>> >>> >>> _______________________________________________ >>> Qgis-user mailing list >>> Qgis-user@lists.osgeo.org >>> 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 >> > -- Alexandre Neto --------------------- @AlexNetoGeo http://sigsemgrilhetas.wordpress.com http://gisunchained.wordpress.com
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