Opened 11 years ago

Closed 7 years ago

#1993 closed task (wontfix)

Improve rendering of tunnels

Reported by: sladen Owned by: osm@…
Priority: minor Milestone:
Component: osmarender Version:
Keywords: tunnel layering Cc:


Currently tunnels disappear under all sorts of things:

  • Roads, rivers, seas, airports

and become invisible, disappearing without a trace. Examples:

  • Helsinki: 60.371,25.095 New harbour freight line, vanishing under a forest (Helsinki is full of trees...)
  • Heathrow: 51.467,0.462 Piccadilly, Heathrow Express, main entrance and cargo tunnels disappearing under Airport apron
  • Thames: 51.464,0.274 Dartford Tunnels and CTRL Thames Tunnel disappearing under estuary
  • Chunnel: 51.098,1.218 Channel Tunnel vanishing under English Channel

Ideally it would be possible to know where the tunnel goes when it passes under roads/forests/buidings and the like. Other existing map makers tend to do by rendering the tunnel as parallel dashed lines (or similar) on top of other features.

One possibility is rendering in two steps, a core centre, and outer lines. One being at the physical level (layer=) and one being overlaid higher-up.

Multiple stacked tunnels should continue to cross each other at the correct level (see Stratford, Kings Cross, etc... unless people have broken the sub-surface layering again).

Change History (3)

comment:1 Changed 11 years ago by Vid the Kid

The problem here isn't the tunnels. It's the areas, which are rendered at layer=0 (unless they're otherwise tagged). Colored areas should be rendered earliest, as if they are layer=-infinity. (And icons and labels should be rendered as if they are layer=+infinity, but that's another issue altogether.)

When a tunnel goes under water, I'm not sure what should be done. I sort of like the behavior that the water covers the tunnel, because it's physically above the tunnel. But when the water is expansive, such as the English Channel, that can be problematic...

comment:2 Changed 11 years ago by sladen

Vid: a map that fails to display information is not a useful map... The ideal is to display *both* tunneled ways and landuse (overlaid) in some manner, rather than just one of them.

comment:3 Changed 7 years ago by iandees

Resolution: wontfix
Status: newclosed

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