Lake IDs at low zooms

[msbarry]

As part of onthegomap/planetiler#227, I added lake OSM IDs but only for lakes from OSM data (z6 and above). Merging with natural earth data is a bit tricky because we process all of natural earth first, then all of openstreetmap.

A few options for how to get OSM IDs on low-zoom lakes:

• store all of the natural earth lakes features in-memory in water profile, add additional info to them while processing OSM elements, then write them out after OSM is finished (like we do with the boundary layer)
• Use OSM lakes at lower zoom-levels instead of natural earth. We could add VW simplification with options like effective/weighted area to planetiler to produce a similar visual effect that natural earth gets with mapshaper
• Extract OSM IDs as part of wikidata pre-processing, then go from wikidata ID to OSM ID when processing natural earth elements

Originally posted by @msbarry in onthegomap/planetiler#227 (comment)
Transferred from onthegomap/planetiler#231

[mmc1718]

Edit: Coming back to this I don't think this is related. If it's still of interest I can make a separate issue and PR for that.

I am working on a project which involves using Planetiler (the OMT profile) and editing the WaterName layer to get lake labels for certain lakes in the natural earth dataset to show from the zoom specified by min_label in the ne dataset.

I found this issue and am wondering if it is related. I am currently using the same approach as for marine points (storing wikidata ids and matching them to the OSM elements

planetiler-openmaptiles/src/main/java/org/openmaptiles/layers/WaterName.java

Line 90 in 6317d82

private final ConcurrentSkipListMap<String, Integer> importantMarinePoints = new ConcurrentSkipListMap<>();

)

I am not sure how this approach compares to the suggested options listed here for the Water layer. My priority is to have labels available at low zooms for the significant lakes, rather than add more lakes to the map.

I would be interested to know whether you see this task as overlapping? If so, I would be happy to work on a PR (also happy to take a different approach to the one I am working on currently if it is preferred)