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# Questions tagged [true-north]

The direction to the geographic north pole.

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3 votes
2 answers
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### Orientation differs between projections. What is the "Real" North? [closed]

Below are two screenshots of the same data, featuring plots of land considered for a photovoltaic array. Depending on the projection used, there is a difference in the orientation of features. (Taken ...
• 405
0 votes
0 answers
197 views

### True north/east in UTM rasters

I have rasters that are in UTM projection (of various zones, depending on the location of the raster) at 10-meter pixel spacing. The rasters are, on average, 29,000 by 21,000 pixels which covers a ...
• 117
1 vote
1 answer
540 views

### EXIF: Can you calculate latitude from longitude value and true north value?

I have an iPhone image that contains the GPS longitude and a bearing relative to True North. Is it possible to calculate the latitude from these two values? EXIF metadata in question: GPS Longitude ...
4 votes
1 answer
3k views

### How to interpret GPSDestBearing and GPSImgDirection?

I need to take some photos capturing the GPS coords and direction of camera. I'm using an iPhone 8+ and this is the relevant output I get from Acute Photo EXIF Viewer: EXIF GPS Tags GPSDestBearing:...
• 93
2 votes
1 answer
5k views

### True-North Bearing between two GPS coordinates

I am trying to find the correct equation to find the bearing off of true-north between two GPS coordinates. I have seen a lot of online calculators and a lot of formulas on this GIS stack exchange, ...
• 181
4 votes
1 answer
1k views

### Calculating convergence angle for point data in QGIS

I have been a user of ArcGIS Desktop for many years and this function is easily done within ArcMap using the 'Calculate Grid Convergence Angle (Cartography)' tool. I am wondering if there is a ...
• 41
3 votes
1 answer
3k 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.)
• 91
1 vote
1 answer
2k 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 ...
• 13
3 votes
1 answer
808 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 ...
• 131
1 vote
0 answers
133 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 ...
3 votes
0 answers
873 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....
• 398
3 votes
2 answers
661 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
1 answer
353 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 ...
1 vote
1 answer
3k 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 ...