Specify per layer min/max zoom?

[jatech1]

Is there any way (perhaps in the layer-json) to specify min/max zoom for each layer? I know I can build each layer separately, and the use tile-join, but that turns one step into 12 steps... I know I can also add a tippecanoe json element to each feature, but that turns a simple config item into a geojson build code change and bloats every geojson file.

If the answer is that it was never added to the layer-json element, is this possible to revisit? If not, is there any drawback in using tile-join as opposed to single native multilayer build in tippecanoe? I assume it has less opportunity to optimize.

Thanks!

[e-n-f]

There isn't a way to do this currently. It doesn't seem like it would be too hard to add; the main obstacle is figuring out a good syntax for specifying per-layer options. Maybe it could fit into the --named-layer format.

tile-join doesn't do any optimizing: either it makes the tile or it doesn't, but it doesn't simplify or drop features.

[jatech1]

Thank you, Erica. I appreciate your help! So it sounds like creating 10 individual pmtiles with tippecanoe and then joining with tile-join, should be pretty much identical to a single combined pmtile file created by tippecanoe? But, obviously, still easier if it can be all built at once by tippecanoe.

As for format, that is what I was thinking, also:
--named-layer={"file":"input.json", "layer":"layer1", "description":"Layer 1 data", "minzoom":2, "maxzoom":10}

If I want to have different min zoom levels for some layers in a single pmtile file (mostly point layers that I do not need at all at 0 or 1 for example), I assume they should all have the same max zoom in order for them to all overzoom beyond maxzoom properly in maplibre? Is that correct, or am I wrong? Does the maplibre style source max/min zoom control the overzoom? ie. if style says max is 10 for a pmtile source, and one of my layer data in the pmtile file ends at 8, will that layer not overzoom properly?

[e-n-f]

Yes, that's right, for maplibre to overzoom these layers they all need to be present in the tiles at the maxzoom level; it will not go looking for them at lower zooms.

[jatech1]

I am going to play with this in the code... I see how the params and sources structs work and can get the min and max zooms into the sources list from the named-layer json... can you point me to the easiest place in read_input to use the source min/max as opposed to the global min/max passed in as params to that function?

[e-n-f]

Thanks! Probably the easiest place to plumb it through will be as part of the serialization_state, which will then be accessible from serialize_feature, which can set the tippecanoe_minzoom and/or tippecanoe_maxzoom before it writes out the serialized feature.