Functional Requirements
[Extract from an e-mail from Ernie Ott, August 2000. This
has been modified based on subsequent discussion]
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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
left out?
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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.
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Our model needs to locate street furniture and rail furniture (e.g. signs,
signal, shelters).
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Our model needs to support the location of a transient feature (a mobile
asset...a bus)
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Our model needs to support events which occur along the road and rail facilities,
or at transfer and support facilities.
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The model needs to support the concept of replacement of facilities which
do not move.
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The model needs to recognize the continuance of a specific facility which
may move to a new location
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The model need only leave a minor hook for transport waterways (canals,
harbours, navigable links)
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The model need not support air traffic, but should recognize air facilities.
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The model should support the idea of facility histories.
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The model should allow histories to migrate the events of facilities to
their "replacement" facilities.
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The model should support user-defined paths;
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The model needs to support temporal comparison of events;
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The model needs to recognize the concept of capacity of the network links.
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The model should differentiate between incident-type events and status-type
events (incidents occur sometime wheras status is always "occurring");
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The model must recognize multiple overlapping networks which re-use basic
links.
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?