OpenStreetMap
In Mapnik rendering of LineSymbolizers, using a stroke-dasharray is incompatible with a stroke-linecap of "round". If you try to combine the two, Mapnik will ignore the stroke-dasharray and, if you're me, leave you very confused as to what's happening.
Diskussioun
Bemierkung vum Andy Allan de(n) 4. Mee 2010 um 10:25 Auer
I don't think that's correct - but you need to be careful on how the gap between dashes compares to the width of the line. So if you have a width of 2px, you'll need a gap between strokes of 5px to see a 1px gap. Each little dash gets rounded, and the round ends aren't counted as being part of the length of the stroke.
Bemierkung vum asciipip de(n) 4. Mee 2010 um 11:33 Auer
Ah, that makes sense. I was using a 4,2 dasharray, so there wasn't room for the gaps to show up.
Interestingly, that means I could make a line of circles if I wanted to.
Thanks for pointing that out!