The limit of TUNNEL is the walls of and openings to the passage.
If TUNNEL provides passage for a hydrographic feature,
Source Interpretation Guidelines
If TUNNEL meets capture conditions and provides passage for another
feature (CANAL/DITCH, PIPELINE with Product = Water),
Then capture both TUNNEL and the other feature.
If a tunnel does not meet capture conditions and carries another feature,
Then capture that feature, and if required, capture UNDERPASS to allow
definition of the relationship between that feature and any other feature over
or under which it passes.
If TUNNEL provides passage for ROAD or RAILWAY,
Then collect in the theme Transportation.
If there are two TUNNEL passages and the overall width is < 100 ft,
If there are two TUNNEL passages and the separation between the
passages is < 20 ft, then capture one instance of TUNNEL.
If TUNNEL is symbolized by a three line symbol,
Then capture as one instance of TUNNEL.
Water tunnels in Hawaii that are shown with the edit symbol are not captured
as TUNNEL. See WELL.
Revision – General
Revision - Standard
Revision - Limited
If the alignment of TUNNEL is unknown,
Then align TUNNEL in a straight line between openings.
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