Increase tertiary/residential/unclassified casing strength

[matthijsmelissen]

White roads (tertiary/residential/unclassified) should contrast sufficiently with features like landcover and buildings, with which they are frequently surrounded. To increase the contrast, I think we need to make the casing of these roads darker.

I created some exaggerated examples for the sake of argument (final choice will probably be less strong).

For those who would like to test with this, see the math1985/stronger-casing branch.

[pnorman]

1st, 2nd, and 3rd look reasonable, perhaps a touch too strong.
3 looks too strong for me.

[imagico]

In my eyes this is too strong - at the moment the white roads' casing seems visually weaker than that of the colored roads. In you examples it looks stronger. The same strength (that would be somewhere in between) might be better.

[matthijsmelissen]

Thanks for the feedback! I submitted a more moderate version of this proposal as PR #2454.

In the PR, the colors are less strong than above across all levels, and in particular the lower ones. Also for service roads, the colors are not as dark.

[matthijsmelissen]

Something I wonder: is a 0.5 pixel wide black line equivalent to a 1 pixel wide gray line?

[imagico]

Evidently not - especially on a black background 😄

What you probably want to know is if a 0.5 pixel black line looks like a 1 pixel black line with 50 percent opacity. Neither is this - although the difference is small and gets even smaller if you compare a 0.25 and a 0.5 pixel line.

[pnorman]

Something I wonder: is a 0.5 pixel wide black line equivalent to a 1 pixel wide gray line?

No - antialiasing will give them a different look, but they're close.

Until you go to a retina display, when they look quite different.