Database Reference
In-Depth Information
Norton Soke
Old Medina Road S1
Medina
Isis
FIGURE 6.7
Decomposing the network further.
However, it is not always sensible to do this. In this case, it is likely that the situa-
tion as described will remain as it is for some time to come. If the single-track section
is upgraded at some time in the future, we could either merge the road sections back
together or just leave things as they are but attribute S3 with having two lanes—the
actual solution will depend on how you want to manage these life cycles. But, what
if the attribute we are concerned with is the position of road signs? In this case, there
is a lot of potential for the roads to become oversegmented and for relatively frequent
changes in the number and position of road signs to generate significant extra work
and change. In this case, it is better to model the road signs as objects in their own
right (as they are) and to link them to the road segment:
Sign M12 has Lat 45.19847.
Sign M12 has Long 5.65332.
Sign M12 has text “Single Track Road Ahead”.
Sign M12 is on Old Medina Road S4.
Sign M12 faces towards Norton Soke.
To record the extent of a road restriction, such as the applicable speed limit, we
can record start and end points, plus the limit:
Speed Restriction 2765 applies to Old Medina Road S4.
Speed Restriction 2765 begins at latitude 45.19659.
Speed Restriction 2765 begins at longitude 5.65347.
Speed Restriction 2765 ends at latitude 45.19661.
Speed Restriction 2765 ends at longitude 5.65344.
Speed Restriction 2765 restricts max speed to 50.
6.6.3.1 Links and Node Network Model
Readers familiar with networks may be surprised that there has been no mention
of the classical link-and-node model for networks. In this model, all links connect
