What is a carto layer?
That's easy! The term "carto" (short for cartographic) has become a kind of standard way of referring to the default style of the OpenStreetMap render. The so-called openstreetmap-carto (osm-carto) has its code base hosted on github and is freely downloadable and installable. The particular style of map render has become idiosyncratic to OpenStreetMap, an aspect of its image or "brand" online, but it is also constantly evolving, with small changes made to the style on an almost weekly basis.
OpenGeofiction uses the same osm-carto style for its main (default) map layer.
Why is OGF's carto layer out of date?
Updating the render software is not a simple task. Therefore we have opted not to try to "keep up" with the osm-carto code base. We anticipate updating maybe once a year or so. The current version of the OGF Carto layer is 5.3.0, and was current as of August, 2021.
Can we customize OGF's carto layer?
In theory yes. In practice, no. It's hard. Sorry. Eventually we may develop a separate, custom OGF render layer, similar to the way the histor layer used to work. This is not currently in development, however.
What are the technical specifications of the OGF carto layer?
The OGF carto layer is called ogf-carto in the code base. It is rendered on the current main render server, tiles04.rent-a-planet.com. This server is also aliased as tile.opengeofiction.net.
You can find the tiles at this path (e.g. for adding as a TMS image layer to JOSM or iD):
Maximum zoom is the same as for OpenStreetMap: zoom=19
It's "layer code letter" is "B" (this is a suffix to the URL, e.g. "...&layers=B") but because it's the default layer, this URL suffix is often "eaten" by the browser.
The topo render database receives incoming replication from the main apidb (opengeofiction.net) which currently "ticks" about every 10 minutes (not minutely, as in OSM).
The OGF carto layer isn't showing something I added/deleted correctly. Why?
We have had problems since the migration to the new platform with occasions where the render data seems to get "out of sync" with the apidb (the map database, AKA rails port). This can result in the persistence of deleted objects in the render, or the failure of newly added object to appear in a timely fashion. We are aware of this problem, and even working to solve it, but currently it is an open, unsolved problem.