diff --git a/Grouped-rendering.md b/Grouped-rendering.md index 807d1e6..ab115b4 100644 --- a/Grouped-rendering.md +++ b/Grouped-rendering.md @@ -1,4 +1,16 @@ -Using "grouped rendering" on a layer renders all styles of one layer for all features that have the same value before proceeding to other features that have a different value. This is useful for rendering roads in the correct z-order: +Using "grouped rendering" on a layer renders all styles of one layer for all features that have the same value before proceeding to other features that have a different value. + +Example syntax looks like: + +```xml + + casing + fill + ... + +``` + +This is useful for rendering roads in the correct z-order: * The datasource (e.g. Postgres) sorts the data based on a field (e.g. z_order) into ascending order * Mapnik paints the features as they come in, but stops when the next feature has a higher z-order than the current one. It then proceeds to paint other styles for the features it has retrieved so far.