Remove woodland graphics beneath an area of Water


If i place an area of water (like a pong or lake) over woodland, the woodland graphics show through beneath the water.
Is there a way to remove the background woodland graphics beneath the water to stop them showing through?


Could you paste an example link and image showing this problem?

This is a known artifact from the way in which the symbology of trees is overlaid on the green base colour of the wood. The various decisions made when introducing the overlay are documented extensively on github.

In most cases the solution, which is probably correct for many purposes is to make the water area an inner member of a multipolygon with the original wood polygon as the outer. (This isn’t perfect because it makes it harder to find lakes & ponds in a wood, but meets most use cases).

Hi James787, If this is the area you are concerned about (, then you need to add the overall forest area into a nested multipolygon. Please see here

Yes, this isn’t perfect, is it? I wonder if it isn’t really that the issue of rendering should be addressed because really smaller ponds in the forest are in fact part of the forest and are even covered by the leaves of the trees. Isn’t it tagging for the renderer to use multipolygons for these cases? Like in former times the layer tag was used.

Yes in these cases it does not make sense to make them inners (closed canopy is a useful rule of thumb). The technical problem lies deep in Mapnik (the decoration has to be at a different level to the colour fill), and at the time it was regarded as a minor deficiency which we could live with (particularly as large bodies of water/grass etc are better represented by excluding them from the woodland, and the artefact of trees over a pond can be regarded as a positive as it shows closed canopy).

Most of these issues can be resolved if one does post-processing of polygons, but the main Carto-CSS map on the website has to be able to update in near real-time, so always uses polygons as is.