The <labelLayer> section: a special layer for icons and labels
All icons and labels are collected and drawn as a separate layer, which is drawn when the <labelLayer> section is interpreted. Icons are drawn immediately before labels. The <labelLayer> tag has no attributes, so you just place
in the style sheet, at the same level as other layers. Normally it is the last item in the style sheet.
You can achieve various special effects by using more than one <labelLayer/> tag. Each label layer draws all the icons and labels that have been stored since the last label layer if any. One application for this feature is to draw icons and labels for routing information independently of all others, and overlapping them.Style Sheets Directory