Questions tagged [true-north]

The direction to the geographic north pole.

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1answer
464 views

How is ST_Azimuth (in PostGIS) calculated?

What algorithms are internally calculated in PostGIS? Can you explain it with simple code? (I want to know the standard of true north.)
0
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1answer
563 views

Using azimuths and bearings in GeographicLib? [closed]

I am currently using the JavaScript port of the geodesic routines from GeographicLib: https://geographiclib.sourceforge.io/html/js/ https://github.com/yurijmikhalevich/node-geographiclib I am ...
2
votes
1answer
484 views

How can I find the average bearing using a set of zig-zaggy coordinates, knowing the user travelled in a straight line during that period?

Some background: I'm developing an app which uses augmented reality and GPS data in order to improve the True North accuracy of the device. Currently, iPhones have a True North accuracy of about 15º ...
1
vote
0answers
54 views

meridian convergence local coordinate systems [duplicate]

I am new to the concept of meridian convergence. I understand that it is the angle between True North and Grid North. But I have problems understanding how meridian convergence affects local ...
2
votes
0answers
419 views

How can I rotate a map layer in QGIS so that center of map always have north upwards?

I'm working in the polar regions and make maps in different scales. The convention is to show e.g. the Antarctic continent with the prime meridian upwards on the map and polar stereographic projection....
3
votes
2answers
162 views

Does Magnetic Deviation depend on altitude? [closed]

Magnetic declination, sometimes called magnetic variation, is the angle between magnetic north and true north. Declination is positive east of true north and negative when west. Magnetic ...
0
votes
1answer
235 views

Make a Declination Arrow for Data Driven Pages?

I am making a map book over a large area and want to add a correct declination arrow for every page. I have not found a way in ArcGIS to make a declination arrow (in 10.3). I could make my own using ...
2
votes
1answer
1k views

Grid or True North In QGIS

With Qgis general settings and changing nothing on the preferences window, which north system (true north or grid north) will be activated ? Would it be determined by selection datum, for instance ...