Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.
Sign up to join this community
It's a little tricky to pick label and feature styles (line thickness, colours, etc) in the map canvas because they don't reflect what I would see in my print composer which is at a different scale because of paper size and such.
I haven't found any options in the QGIS options or project properties.
In QGIS it's not called Reference Scale.
You can make sure line thickness and font size are visually the same in the map canvas and the print composer (regardless of paper size and extent) if you size your font labels and line styles using Map Units instead of points, mm, etc...
There is also the option to use non-map units, and in that case you can just set the map canvas scale to match whatever scale you want to print at to get a quick visual (but not if your map takes a while to render).
You can calculate the "viewing scales" by your preference and then save them for future use using scale templates in QGIS - exporting the scales to XML and then referring to that XML in future map projects.
Settings menu > Map Tools
Add/remove your preferred scales, then click the SAVE button to save those scales as an XML. later you can load those scales from the XML into new documents.
It would be much easier to enter a reference scale and then give stroke weights and text sizes in paper units for that scale, and have QGIS calculate the rest. I know what kind of stroke weights I need on a map (for example 0.35 pt or 0.125 mm for a countour line), independent of scale. In QGIS now, If I want it to show my map as it will printed at all zooms, I would have to calculate the line weights in meters for every scale. It also makes it much easier if you need to change the reference scale at some stage in the project.
It is possible, in the properties of each layer, go to the "Representation" tab and check "Fixed Reference Scale", indicating the scale we want. You have to do it for each layer, it is a property that QGIS assigns to the symbology of the layer, not to the project or the composition.
