[Extract from an e-mail from Ernie Ott, August 2000. This
has been modified based on subsequent discussion]
What's next? I hope while you guys are flaying this document, we discover
direction in its pitiful screams. So, what is useful in this, what gets
dissected, embellished, tossed out, and/or smushed together?
Our model needs to identify the location of transportation facilities,
both in a 1-D and 2-D sense. By 1-D I mean LRS: linear distance along a
network. By 2-D I mean "x,y"-based location. I am willing to be talked
into 2.5-D and/or 3-D if you think it is the same amount of work.
What are the implications of restricting this to 2-D — will any users be
Our model needs to differentiate between Road, Rail, Transfer Facility,
and Support Facility infrastructure, both from a facility type differentiation
as well as a network topology separation.
Our model needs to locate street furniture and rail furniture (e.g. signs,
Our model needs to support the location of a transient feature (a mobile
Our model needs to support events which occur along the road and rail facilities,
or at transfer and support facilities.
The model needs to support the concept of replacement of facilities which
do not move.
The model needs to recognize the continuance of a specific facility which
may move to a new location
The model need only leave a minor hook for transport waterways (canals,
harbours, navigable links)
The model need not support air traffic, but should recognize air facilities.
The model should support the idea of facility histories.
The model should allow histories to migrate the events of facilities to
their "replacement" facilities.
The model should support user-defined paths;
The model needs to support temporal comparison of events;
The model needs to recognize the concept of capacity of the network links.
The model should differentiate between incident-type events and status-type
events (incidents occur sometime wheras status is always "occurring");
The model must recognize multiple overlapping networks which re-use basic