Canal tunnel should draw under pedestrian plaza

[zerebubuth]

• What did you see?

The Canal Saint-Martin near Bastille, Paris. However, it is covered and there's a pedestrian plaza on top of it, so we shouldn't be able to see it.

• What did you expect to see?

The riverbank underneath has tunnel tags, and this should mean the draw order is reduced and it draws underneath the pedestrian plaza.

• What map location are you having problems with? City and country are helpful, as well as tile coordinates or latitude / longitude.

https://tangrams.github.io/walkabout-style/#17.466666666666676/48.85481/2.37024

• Screenshot? Props for animated gifs.

[nvkelso]

Looks like the sort_rank for several water features needs adjusting to be below landcover layer feature's z-order.

[nvkelso]

• On the top garden boxes: https://www.openstreetmap.org/relation/1602306#map=19/48.85435/2.36967
• In the middle: pedestrian plaza polygon: https://www.openstreetmap.org/relation/1602299
• We should see water on the bottom:
  • -1 https://www.openstreetmap.org/way/236735251#map=19/48.85355/2.36953
  • -2 https://www.openstreetmap.org/way/236735249#map=18/48.85422/2.36991

[nvkelso]

Fixed via #1951.