[pgrouting-dev] Time dependent data and input format

[Jay Mahadeokar]

Hi,

Lets use this thread for discussion on following points:

1. What should be the input format for time dependent data?

2. What are the options to obtain real world time dependent data? If it is
not freely available, then what are the alternatives to test our code?
(randomly generated time dependent data would be rather inadequate)

*Input format for time dependent data:

*There has already been a brief discussion on this topic before. A quick
recap:

According to Stephen:

   - It is better to assume data to be present in a simpler model that is
   easy to work.
   - It is better to have 5 simple to work with tables than 1-2 complex
   ones.
   - We can then provides data loaders that will convert the data from
   different format into our designed model.

Daniel had listed many possible scenarios in which time-dependent shortest
path can be applicable.

*Some Ideas:

*The edge cost will eventually be a function of following (please feel free
to add any new points):

   - Time
   - Vehicle type

For time, each discrete time interval can have one entry per edge. If we
assume t time intervals (which can be as small as 5 minutes as available in
commercial Navteq time dependent data) there would be |E| * t entries.

For vehicle type again if we consider v vehicle types, there will be total
|E| * t * v entries.

So, besides the edges table that has entries for every edge and other edge
related information (like ways in Barcelona dataset), we can have another
table with columns:

   - EdgeID
   - vehicleType
   - TimeInstant
   - Cost

Once / if we are able to acquire any real world time dependent data, we can
then write data loaders that would convert the data into our format.

Comments / improvements welcome.

-- 
Regards,
-Jay Mahadeokar
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