27d7da41_mGeoJSON___University_Map_Wiki__lines
[property name] stroke-dasharray [filled shapes] dash pattern for outline [notes] a string, one of "-", ".", "-.", "-..", ". ", "- ", "--", "- .", "--.", "--.." forming a mixture of dashes and dots accordingly. Note that this is not the same as the SVG property stroke-dasharray, but derives from the cross-browser Raphaël system (documentation). [lines] 
dash pattern of line
UCamGeoJSON - University Map Wiki
lines