<p dir="ltr">Right, this looks promising.</p>
<p dir="ltr">I have been changing projections and then enabling the grid decoration which is always oriented straight up regardless of the projection.</p>
<p dir="ltr">I assume that you were inserting your grids as a vector feature using a drawing tool?</p>
<p dir="ltr">What was the CRS of the grid layer? I have been changing the project projection with OTF on. Maybe I should be adjusting the projection of the layer in question?</p>
<p dir="ltr">Thanks again . . .</p>
<p dir="ltr">Cheers . . . . . Spring<br>
Samsung Tab 4</p>
<div class="gmail_quote">On Apr 4, 2018 5:23 AM, "Kristian Evers" <<a href="mailto:kreve@sdfe.dk">kreve@sdfe.dk</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="white" lang="DA" link="blue" vlink="purple">
<div class="m_-6141100602306523787WordSection1">
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">I had a quick go at it after I wrote the email. What I did was to first create a custom projection with the proj-string
“+proj=merc”. Then I opened the layout editor, inserted my map and added to sets of grid lines to the map. One of them was left with the original CRS (the UTM one) and for the other I used my custom CRS. This immediately gave me two grids, one where the meridians
is oriented at the grid north (black in the attached image) and one oriented at true north (red in the attached image).
<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">/Kristian<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
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<div style="border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Fra:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"> Springfield Harrison [mailto:<a href="mailto:stellargps@gmail.com" target="_blank">stellargps@gmail.com</a>]
<br>
<b>Sendt:</b> 3. april 2018 22:52<br>
<b>Til:</b> <a href="mailto:qgis-user@lists.osgeo.org" target="_blank">qgis-user@lists.osgeo.org</a>; Kristian Evers <<a href="mailto:kreve@sdfe.dk" target="_blank">kreve@sdfe.dk</a>><br>
<b>Emne:</b> Re: [Qgis-user] True North<u></u><u></u></span></p>
</div>
</div>
<p class="MsoNormal"><u></u> <u></u></p>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt">OK, that sounds like the solution I'm looking for.<br>
<br>
It sounds like the answer is to draw the lines in one projection and then transform it to the other, depending upon which orientation is desired for those lines.<br>
<br>
I hope I have this correct…<u></u><u></u></p>
<div>
<p class="MsoNormal">Cheers . . . . . Springfield Harrison<u></u><u></u></p>
</div>
<p class="MsoNormal"><br>
<br>
On 03-Apr-2018 02:46, Kristian Evers wrote:<u></u><u></u></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">You can use the Mercator projection to digitize true north lines. It is conformal and thus preserves angles. The meridian
convergence is 0 (that is, true north == grid north) all over the map. If you then transform those lines to your chosen CRS you should have a set of lines pointing towards true north instead of grid north.</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">/Kristian</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span><u></u><u></u></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Fra:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Qgis-user [<a href="mailto:qgis-user-bounces@lists.osgeo.org" target="_blank">mailto:qgis-user-bounces@<wbr>lists.osgeo.org</a>]
<b>På vegne af </b>Alexandre Ne</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">to<br>
<b>Sendt:</b> 3. april 2018 11:15<br>
<b>Til:</b> Springfield Harrison <a href="mailto:stellargps@gmail.com" target="_blank"><stellargps@gmail.com></a><br>
<b>Cc:</b> qgis-user <a href="mailto:qgis-user@lists.osgeo.org" target="_blank"><qgis-user@lists.osgeo.org></a><br>
<b>Emne:</b> Re: [Qgis-user] True North</span><u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">Maybe something like this :<u></u><u></u></p>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><a href="https://gis.stackexchange.com/q/115531/6191" target="_blank">https://gis.stackexchange.com/<wbr>q/115531/6191</a><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt">Alexandre<u></u><u></u></p>
<div>
<div>
<p class="MsoNormal">A ter, 3/04/2018, 10:11, Alexandre Neto <<a href="mailto:senhor.neto@gmail.com" target="_blank">senhor.neto@gmail.com</a>> escreveu:<u></u><u></u></p>
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<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt">
<p class="MsoNormal">Ah sorry, <u></u><u></u></p>
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<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">I got lost in translation. You are right, I was talking about the magnetic north, not the geodetic one.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Meanwhile, remembering that all UTM are Transverse Mercator, I don't think there's a CRS that will solve you question.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">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. <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Alexandre <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"> <u></u><u></u></p>
<div>
<div>
<p class="MsoNormal">A ter, 3/04/2018, 09:25, Springfield Harrison <<a href="mailto:stellargps@gmail.com" target="_blank">stellargps@gmail.com</a>> escreveu:<u></u><u></u></p>
</div>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt">
<p>Alexandre,<u></u><u></u></p>
<p>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.<u></u><u></u></p>
<p>The other North orientations are magnetic north and grid North and these do vary as you suggested.<u></u><u></u></p>
<p>I do need to use a UTM projection but need bearings to be in degrees true north.<u></u><u></u></p>
<p>Thanks Alexandre...<u></u><u></u></p>
<p>Cheers . . . . . Spring<u></u><u></u></p>
<p>Samsung Tab 4<u></u><u></u></p>
<div>
<p class="MsoNormal">On Apr 2, 2018 4:27 PM, "Alexandre Neto" <<a href="mailto:senhor.neto@gmail.com" target="_blank">senhor.neto@gmail.com</a>> wrote:<u></u><u></u></p>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt">
<p class="MsoNormal">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. <u></u><u></u></p>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">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. <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">If you are at a larger scale, then you may need to use different magnetic declination values for each observation. <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">This may help:<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><a href="https://www.ngdc.noaa.gov/geomag/declination.shtml" target="_blank">https://www.ngdc.noaa.gov/<wbr>geomag/declination.shtml</a><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Best Regards, <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt">Alexandre Neto <u></u><u></u></p>
<div>
<div>
<p class="MsoNormal">A seg, 2/04/2018, 23:54, Springfield Harrison <<a href="mailto:stellargps@gmail.com" target="_blank">stellargps@gmail.com</a>> escreveu:<u></u><u></u></p>
</div>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt">
<p class="MsoNormal">Hello,<br>
<br>
I am using CRS 26910, NAD83 / UTM zone 10N, and need to draw lines at<br>
exact true bearings. The Advanced Digitizing Tool seems to do this but<br>
which CRS would I use to ensure that the bearing is True?<br>
<br>
Thanks very much . . .<br>
<br>
<br>
Cheers . . . . . Springfield Harrison<br>
<br>
<br>
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</div>
</div>
<p class="MsoNormal">-- <u></u><u></u></p>
<div>
<div>
<div>
<p class="MsoNormal">Alexandre Neto<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">---------------------<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">@AlexNetoGeo<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><a href="http://sigsemgrilhetas.wordpress.com" target="_blank">http://sigsemgrilhetas.<wbr>wordpress.com</a><u></u><u></u></p>
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<p class="MsoNormal">-- <u></u><u></u></p>
<div>
<div>
<div>
<p class="MsoNormal">Alexandre Neto<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">---------------------<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">@AlexNetoGeo<u></u><u></u></p>
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<p class="MsoNormal"><a href="http://sigsemgrilhetas.wordpress.com" target="_blank">http://sigsemgrilhetas.<wbr>wordpress.com</a><u></u><u></u></p>
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<p class="MsoNormal"><a href="http://gisunchained.wordpress.com" target="_blank">http://gisunchained.wordpress.<wbr>com</a><u></u><u></u></p>
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<p class="MsoNormal">-- <u></u><u></u></p>
<div>
<div>
<div>
<p class="MsoNormal">Alexandre Neto<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">---------------------<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">@AlexNetoGeo<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><a href="http://sigsemgrilhetas.wordpress.com" target="_blank">http://sigsemgrilhetas.<wbr>wordpress.com</a><u></u><u></u></p>
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