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I am working in QGIS 2.16.2 on an atlas comprising approximately 60 locations in 7 states from Texas to Florida to Ohio. Each location has a different coverage area that scales based on the size of circle polygons in a hidden coverage layer.

I would like my scalebar to show distances in miles because it is more intuitive to the client than meters or km. I have accomplished this by setting the units to feet with a label unit multiplier of 5280. Segments are set to "right 4" with fit segment widths of "min 50 mm" and "max 80 mm".

The problem I am having is that the divisions in the scale bar divide to a nice, round number before applying the multiplier (5280), so I get divisions like 1.51515 miles. I currently have the project projection in 3857 (pseudo-Web Mercator). I am open to other projections, and considered 2163: US National Equal Atlas Area, but that is still based on meters and I have the same issue. I could try a state plane based on feet, but I am not working in one particular state and I still have the 5280 multiplier. I am not aware of any projections with miles as units.

I have tried setting the map measurement units to miles under the Project Properties --> General menu, to no avail. If I do a fixed width segment of 5280 units on the scale bar, I get a nice result but it is always limited to 4 miles, even if the map is 400+ miles across.

Is there a way to get nice, even numbered divisions (like 1, 1.5, 2) while using a label unit multiplier like 5280? Or is there another way to have the automatically generated scale bars show miles nicely?

What I have: What I Have or Scale Changes

What I want: What I Want

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This isn't a solution to the root problem, but here is a workaround for your particular situation. Divide the coverage layer into several layers of approximately the same scale. Then create a separate atlas for each coverage area. So you would have one atlas where the maps are less than 10 miles wide, another atlas where they are 10-50 miles wide, another where they are 50-400 miles wide. Use a fixed width segment of 1 mile for the atlas with the smallest map size, 2 miles for the next size, and 5 miles for the largest size.

  • Thanks for the idea! I would need to restructure the numbering on the pages, but that wouldn't be too bad. I sent the client a draft version with no scale bars, which I'm sure violates a cartography rule somewhere. Instead, I used buffers of 10 mile and 100-mile radii with solid green and dashed orange formatting, respectively, around each point. Not perfect, but it provided some visual sense of scale. Depending on what the client thinks, I may come back to your idea. – Nate Wanner Nov 7 '16 at 16:53

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