Further simplification of street network on low zoom levels: neatnet

[do-me]

Hi,
I just came across some recent work of street network simplification with neatnet. Maybe it might be an idea to apply this algorithm to lower zoom levels to save a few more megabytes.

More concretely, features like these freeway junctions

aren't recognizable anyway on zoom levels like this

Just as an idea for further discussion.

References:

• https://uscuni.org/neatnet/
• https://martinfleischmann.net/simplification-of-street-networks/
• https://uscuni.org/talks/slides/202504_GISRUK_simplification.html#/title-slide

P.S. just realized I'd better opened this issue under the basemaps repo.

[bdon]

We already do network-based simplification in https://github.com/protomaps/basemaps/blob/main/tiles/src/main/java/com/protomaps/basemap/postprocess/LinkSimplify.java - the main limitation is that we do not have a full global-scale view ever in memory in the current build process, only a per-tile view.

[do-me]

Thanks, that's a good point I was not aware of at all. I assumed these algorithms were applied globally already.
Enhancing the build process with such a global optimization would probably come at the price of having to rewrite the whole build pipeline maybe on a per-feature basis? Seems like a major effort that is not feasible at the moment. Also it would add additional complexity/build time of course.

[bdon]

If there is globally optimized datasets, those could be created in a different project and imported as GeoPackages into the tiling pipeline, similar to how Natural Earth and preprocessed OSM land/water are treated now.