Maybe something like this : https://gis.stackexchange.com/q/115531/6191
Alexandre A ter, 3/04/2018, 10:11, Alexandre Neto <senhor.n...@gmail.com> escreveu: > 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 > -- Alexandre Neto --------------------- @AlexNetoGeo http://sigsemgrilhetas.wordpress.com http://gisunchained.wordpress.com
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