[docs] add highest zoom levels

[kkowalsky]

we do a good job of documenting where the switch over from Natural Earth to OSM occurs at zoom 8, but we should describe what the highest zoom level is

[nvkelso]

Like zoom 16?

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On Mon, Jan 30, 2017 at 10:04 AM, Katie Kowalsky ***@***.***> wrote: we do a good job of documenting where the switch over from Natural Earth to OSM occurs at zoom 8, but we should describe what the highest zoom level is — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1161>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA0EO3-hAYDVLlHi_pTwqN21BiIbUF38ks5rXiYzgaJpZM4LxucH> .

[kkowalsky]

here's @hanbyul-here's example that we should clarify:

"ex. I am overlaying custom tile over our vector tile and thought our vector tile's highest zoom is 16.
I prepared the custom tiles up to 16 and found out it doesn't really align with our vector tile when the map is zoomed more than 16"

[nvkelso]

Currently our default `max_zoom` hosted service config is setup to to be zoom 16 and we recommend people "over zoom” client side (both Tangram and MapboxGL have convenience properties for this). For clients like D3 and Unity we currently allow server-based over zooming where if the client requests a zoom 17 tile the server will over zoom it. This is not a efficient code path, though. I’ll followup with Hanbul to find out about "I prepared the custom tiles up to 16 and found out it doesn't really align with our vector tile when the map is zoomed more than 16”.

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On Mon, Jan 30, 2017 at 10:18 AM, Katie Kowalsky ***@***.***> wrote: here's @hanbyulhere's example that we should clarify: "ex. I am overlaying custom tile over our vector tile and thought our vector tile's highest zoom is 16. I prepared the custom tiles up to 16 and found out it doesn't really align with our vector tile when the map is zoomed more than 16" — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#1161 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA0EO2pG_uur88Jhbs0jyuhhTb9sTtEwks5rXimGgaJpZM4LxucH> .

[hanbyul-here]

I think this screenshot would explain what I meant. Colored buildings are from my custom tiles.

You can see that it is not aligning with roads from Mapzen Vector Tiles. I wondered this happened because two tile sets zoom levels were not matching. (While vector tile has higher resolution than zoom 16 , custom one interpolates from zoom 16.)

Since @nvkelso mentioned that our tile maxzoom is 16, maybe some this is happening from othere reasons.( road style of basemap styles can be too thick for this data? etc..)

but still, it would be good to document this!

[nvkelso]

We can document suggested "maximum" {z} values of 16 (for default 256px tiles) and 15 (for optional 512px tiles) in https://github.com/tilezen/vector-datasource/blob/master/docs/use-service.md#use-the-vector-tile-service.

But we shouldn't add details to address @hanbyul-here's comment in #1161 (comment) – that's just a natural artifact of combining different sources which different quality issues. There are things we could do in Mapzen basemaps to style the roads thinner at high zooms to reduce the overlap – but some of the overlap is likely due to miss-classification of the roads in OpenStreetMap and miss-match in geometry digitization details between the sources (I suspect the buildings are higher quality and OSM should move around the roads).

[hanbyul-here]

Yess I agree with @nvkelso . I think it will be still useful for users to know when Mapzen tiles become interpolated (zoom 16).