[GRASSLIST:1301] Re: Bridge problem in 2D topological network

[Radim Blazek]

On Friday 19 September 2003 03:03, nicholas.g.lawrence at 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