Stroke border

[paul]

A "border" property to stroke elements is proposed. One way to think of it would be as a stroke applied to both sides of the "main" stroke. A stroke border helps common display tasks such as casing on a streets layer, which are usually polylines, and so themselves represented by a single stroke). This example can currently only be accomplished with a hack: adding a duplicate style below and setting its width to be wider than the street stroke style above. The hack has at least the downside of preventing the entire layer from being less than 100%, lest the color of the border style bleed through and add with the street style.

[paul]

The interface for this could be represented, for example, in a mapnik XML file thusly:

<CssParameter name="stroke-border-width">2</CssParameter>
<CssParameter name="stroke-border-color">#999999</CssParameter>

[Skywave]

Kick, because this would imo a great idea. Also would simply the osm.xml file dramatically.

[springmeyer]

Yup, +1, this is a great idea.