Label for larger bodies of water in Slippy standard view

[David-Duffy]

As per the discussion on:

https://help.openstreetmap.org/questions/34585/names-of-large-lakes-not-appearing-at-any-zoom-level?page=1&focusedAnswerId=34591#34591

Reading a map, I use (major) lake names to work out where I am, as well being interested in what body of water I am looking at.

Is it possible to either
a) show lake labels in the standard view at, say, z10 (as used in humanitarian view)
or
b) show a label if the polygon area is above a threshold - either absolute area, or proportion of current view, where the label would appear centred in the visible water.

[Rovastar]

Yeah that is possible and sensible. I would be against a) though as small "lakes" tagged might be rendered.
b) is possible but more of an issue.

[David-Duffy]

FWIW, labels for islands in the lake appear at zoom >= 12, but for the lake itself at zoom >= 15

[matkoniecz]

According to

openstreetmap-carto/amenity-points.mss

Line 578 in 7c56d82

[zoom >= 15] {

labels on natural=water will be rendered from zoom level 15 using this style. Humanitarian layer is smarter and labels may be rendered from z10, depending on area - see https://github.com/hotosm/HDM-CartoCSS/blob/c101c2c20777e9653001fc4a5c60adaaed57773a/labels.mss#L416

Note that Humanitarian layer is NOT released under open license so it is necessary to either wait for hotosm/HDM-CartoCSS#237 (and hope that they will not only decide to use open license but that they will also release it under something compatible) or redo this work.

[pnorman]

The license isn't really an issue, as we'd have to rewrite any logic, and the logic they do have is pretty trivial. I'd also probably do area filtering a different way anyways.

[matkoniecz]

see also https://trac.openstreetmap.org/ticket/5030

[imagico]

Glacier labels already use limits based on area, see https://github.com/gravitystorm/openstreetmap-carto/blob/master/water.mss#L55 - although these rules could well be extended to lower zoom levels and larger areas.

In general variable zoom limits based on way_area would also make a lot of sense elsewhere - like for the islands as well demonstrated by the french style (https://github.com/cquest/osmfr-cartocss/blob/master/placenames.mss#L55)

[daganzdaanda]

+1 for names on big lakes appearing earlier. On really large lakes, z=8 or even 7 would be OK.

In general variable zoom limits based on way_area would also make a lot of sense elsewhere

Yes, pretty much everything could profit from size-aware rendering. And someone (pnorman?) said, it's actually not affecting rendering performance much at all. So let's use way_area a lot!

Another thing about lakes: The big lakes themselves should also appear earlier, and smaller stuff later.
At the moment, all natural=lake|water; landuse=reservoir|water and waterway=riverbank appear at zoom >= 6. Rendering the small stuff later would fix #73 and look better IMHO. And on the other end there are huge lakes that could be rendered at zoom=3 already. Maybe having 3 groups would be best: huge - large - and the rest