Shortest Path Transcript File in Module 6.15

Module 6.15, ``Plot shortest paths on auto network'', is a very powerful tool for analyzing shortest paths, path trees and accessibility based on distance, time or generalized cost. With the module specific crosshair commands, a user can easily query the distance of an individual node from/to the root node, and also change the direction and the root node of the displayed path tree.

While the displayed graphic information on the screen is very intuitive and easy to understand, it is strictly interactive and thus limited to the screen. In the past, many users have asked us to provide a possibility to write the same type of information into a report or punch file, in order to keep a record of the results or to allow further post-processing of this type of information.

For this purpose, Release 9 extends the concept of transcript files, already implemented in module 2.12, to module 6.15. Once the transcript file feature is activated via a new module parameter, a transcript of all interactive path queries will be written into a batch output file while the user is working with module 6.15. This transcript file contains the following information:

• Standard batch output file header containing module, date/time, user, project and scenario identification (once per module call).
• Mode and distance measure used for shortest paths (once for each plot preparation).
• For each O-D path which is queried interactively using crosshair commands, an entry containing: from node, to node, distance, time or cost (depending on the selected distance measure) and the node sequence of the shortest path that was computed and displayed.

The following example illustrates the format of the shortest path transcript file:

c EMME/2 Module: 6.15(v8.03)   Date: 1998MA30 17:54   User: E001/SPIESS-5...HS
c Project:       TEST STANDARD AND MARGINAL CONICAL VOLUME-DELAY FUNCTIONS
c Scenario 1000: Base Year 1995
c
c Active auto mode:        c car       
c Shortest paths based on: gen.cost=  .876*length+     1*timau            
c
c   from     to   cost  path:
a   1024     16  13.56   1024   1043   1044   1045   1046   1047   1050   1051 
                         1059   1055    165    166    167    168    202    221 
                          219    218    217     16
a   1024    131 22.357   1024   1043   1042   1025   1021   1005    981    966 
                          948    937    931    917    901    898    899    887 
                          598    599    600    601    602    603    604    605 
                          606    607    670    669    667    659    658    656 
                          655    654    131
a   1024     75 26.096   1024   1043   1042   1025   1021   1005    981    966 
                          948    937    931    917    901    898    899    887 
                          598    599    600    601    602    603    604    605 
                          606    607    608    516    517    518    519    527 
                          533    534    535    540    579    578     75
a    149     75 40.016    149    248    247    288    289    320    319    318 
                          317    316    315    312    309    302    304    412 
                          411    410    413    414    415    423    436    437 
                          438    439    497    496    495    538    537    536 
                          535    540    579    578     75
a    131     75 27.421    131    654    655    656    658    659    667    669 
                          608    516    517    518    519    527    533    534 
                          535    540    579    578     75
a   1024     75 26.096   1024   1043   1042   1025   1021   1005    981    966 
                          948    937    931    917    901    898    899    887 
                          598    599    600    601    602    603    604    605 
                          606    607    608    516    517    518    519    527 
                          533    534    535    540    579    578     75

A new interactive query command ``b'' (for batch) has also been added to module 6.15, in order to facilitate the generation of a file containing the path information for all currently displayed paths. When the ``b'' command is entered at the crosshair, the entire current shortest path tree (i.e. paths from the current root node to all leaf nodes or v.v.) will be punched into the transcript file.