[GRASSLIST:1296] Bridge problem in 2D topological network

GRASS GRASS user
1

I was thinking about the difficulty in representing a bridge
in a 2D topological road network.

Could a "turns" attribute be the solution? This attribute would
indicate which turns are legal at each intersection. A bridge
would then be a standard + intersection, with each road
being restricted in it's "turns" to only the road directly
ahead.

nick

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2

On Friday 19 September 2003 03:03, nicholas.g.lawrence@mainroads.qld.gov.au wrote:

I was thinking about the difficulty in representing a bridge
in a 2D topological road network.

Lines may cross without intersection.

Could a "turns" attribute be the solution? This attribute would
indicate which turns are legal at each intersection. A bridge
would then be a standard + intersection, with each road
being restricted in it's "turns" to only the road directly
ahead.

Attribute of what?
To store such information you need a matrix for relation between all
roads in both directions, it is kind of application, not general GIS.

Radim