Set transparent_color on TMS

Question

I'm using a TMS which Tiles are mostly white with some Lines e.g. Roads in different colors. I would like to use this TMS but change the white parts of the Tiles to transparent so it can be overlayed on a TMS with Arealimages.

If I understand right WMS are having an image-parameter to do this:

  image:
    transparent_color: '#ffffff'
    transparent_color_tolerance: 0

Is there an option to convert a color of Tiles of a TMS to transparent?

Answer 1

You are right that this option only exists for WMS sources.

As a hacky workaround you could add the TMS as source to your MapProxy, expose it as WMS layer, use that WMS layer as another source in the same MapProxy configuration, enable the transparency option for that and finally expose that cascaded source (with the original source wrapped inside) as a layer for use in your client(s).

Depending on your data this might be slow, have reduced image quality and potentially some issues with CRSs. But it is possible.