Matt Amos

Having an additional tag for the `burrito` type sounds great to me. I can't find any other attempts to describe that in the data, so it seems worthwhile documenting the...

I agree - we can be more explicit about the values we're including, or the lists of keys we expect from the database. That, plus documentation strings and "for more...

Since #1771, this might be within reach? Worth another look soon?

I'm in favour of going with the same technique we're using [for landuse](https://github.com/mapzen/vector-datasource/blob/master/data/functions.sql#L3-L35) which guarantees we know which values we're dealing with. Anywhere we're doing `COALESCE(raw_column, raw_column, ...)` we're potentially...

Yup, another advantage is that we can be very explicit about which values we're outputting in the docs. But the disadvantage is that it means we'd need a code /...

Comment from Slack, for context: > boundaries are gappy where there's two polygons with tangential sides. both subtract each other's boundaries. > > the previous approach (unioning all the water,...

Hopefully this diagram will help explain what's going on. We have data from the database which is like the top row, with water polygons overlapping. The tops of the polygons...

Looks similar to #99. It seems likely that it's the same cause.

The [data source](https://github.com/tilezen/joerd/blob/master/docs/data-sources.md) for low zooms is likely to be [ETOPO1](https://www.ngdc.noaa.gov/mgg/global/) which does come in "ice sheet" or "bedrock" versions, and it looks like [we used the "bedrock" version](https://github.com/tilezen/joerd/blob/20b4512754490477b0594e3017b278361ad5af80/config.example.yaml#L24). This...

Great, thanks! What do you do to make valid polygons? Perhaps there's a small bit of software we can extract and reuse?