Magnetic north lines are lines placed on the map pointing to magnetic north. On orienteering maps, these are typically always orientated to be parallel to the sides of the paper map, i.e. the map contents are rotated from true north to account for magnetic declination at that location. Rogaine and adventure racing maps are less strict, and the map contents can be rotated at any angle on the map page to best suit the map contents.
Magnetic north lines can be added to a map in QGIS using a number of different methods. A couple of options are described below.
Magnetic north lines can be added using the 'Vector creation > Create grid' tool inbuilt in QGIS. See the following video which describes the process.
Magnetic north lines can be added to the map using a large polygon over the map area, with a line pattern fill at a suitable angle to account for magnetic declination. The process to follow is:
Layer > Create Layer > New Shapefile Layer...
In the 'New Shapefile Layer' window, select Geometry type: Polygon, and then OK. This will add an empty layer to the project.
Toggle editing for this new 'north lines' layer, and 'Add Polygon Feature'. Draw a large polygon over the map area.
For this new 'north lines' layer, go to Properties > Symbology > Symbol layer type: Line Pattern Fill.
Set the Line Pattern Fill style as:
Rotation: degrees required to suit magnetic declination and map orientation. Note: when in the Print Composer, the line pattern fill does NOT rotate when applying a map rotation angle. Any rotation of the north lines needs to be applied using the Line Pattern Fill style rotation angle.
Spacing: typically this is 1km spacing for rogaine maps (1000 map units or 1000 meters at scale).
Set the Simple Line style as (this is the style for the lines themselves within the line pattern fill):
Color: Purple, e.g. HTML notation #a626ff
Stroke width: 0.2mm
For an example map which uses this approach, refer to the Girraween 6hr 2020 map.