ALK Flow
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1. Another way to get the same matrix in the TRGRAPH workspace is to use the function GETVOL in TRGRAPH Rather than specifying a railroad as the left argument 0 indicates that all railroads are to be summed for that link VOL lt 0 GETVOL WB00 or VOL lt 0 GETVOL c ptnmw user WBO00 tf1 Bad File The Bad file is a fixed length text file containing the results from the node cleanup process The output is of the form Old Node New Node RR Cars Distance Two sample records might look like this 31563 31515 777 40 13 488 0 105 120 760 In the first record the node 31563 was found not to be on Burlington Northern Santa Fe 777 The closest node that BNSF serves 31515 was 1 3 miles away The distance was within the maximum cleanup distance specified In the second example node 488 was found not to be served by Canadian Pacific 105 The next nearest node to 488 that CP serves was 76 miles away which is more than the maximum allowable cleanup distance Therefore this record was not cleaned up indicated by the zero in new node spot2. only if the user selected Valid Service Type in the second tab The second option lets the user pick one of the generic routing formulae BESTROUTE ROUTE 2 ROUTE 3 ROUTE 6 or DISTANCE Alternatively a user defined routing formula a vector with impedance values for each link can be selected using the third option If you want the routing to respect family definitions for carriers and allow reciprocal operating rights for each carrier within a corporate family check the corresponding box A bad node not served by the corresponding railroad can be cleaned up to the nearest node on the railroad subject to a maximum distance from the original node You can specify this distance in miles in the box next to Bad Node Clean up Radius ALKFLOW User Manual Page 7 The last item on this tab is the Procedure for Absent Carriers The user can select either Error Cartesian or Any Carrier depending on whether he wants an error message Cartesian distance calculation distance as the crow flies or routing through any other carrier for AB Pairs when the carrier specified in the A B pair does not exist on the network FLOWTRAFFIC Tab 4 Output A Bs TEA TA ALKFLOW Control Panel 101 xj Main Input Fields Routing Output A Bs Output Miled ABPAIR File mil Append Summed Network Quantity from Below DIST Bad Route Summed Value 39333 T Append Summed Quantity from Input File Below l Width
3. AL ALK Technologies Inc ALKFLOW Traffic Assignment Workspace User Documentation Copyright 2003 ALK Technologies Inc All rights reserved Table of Contents Introduction to ALKFLOW Loading ALKFLOW Inputs to ALKFLOW The Network AB Pairs Flow Traffic sisi Bes asia Busen FLOWTRAFFIC Tab 1 Main FLOWTRAFFIC Tab 2 Input Fields FLOWTRAFFIC Tab 3 Routing FLOWTRAFFIC Tab 4 Output A Bs Executing FLOWTRAFFIC Outputs of FLOWTRAFFIC Miled ABPAIRS Flow File Total Flow File Bad File ALKFLOW User Manual Page 1 Introduction to ALKFLOW ALKFLOW is one component of the Princeton Transportation Network Model and Graphic Information System PTNM ALKFLOW like TRGRAPH is a Dyalog APL W workspace It provides the user with the ability to route traffic data over transportation networks In other words ALKFLOW takes traffic volumes and on line point off line point information and determines the set of links over which the traffic would travel based on criteria that the user provides Output from ALKFLOW includes data on the routes e g distance traveled and directional volume data on the network links The process is called traffic assignment or flowing the traffic The workspace has been designed primarily for calculation and therefore has no function to perform graphics However the outputs of TRGRAPH are fully compatible with the workspace TRGRAPH and can be displayed easily using the strong graphics capabilit
4. ce type optional input e Voll etc are the volumes of certain kinds of traffic moving from A to B on the railroad such as cars or tons For example the AB pair may be 802 16434 16710 2 250 10000 In this case the railroad is Union Pacific 802 the on line point is Chicago 16434 the off line point is Los Angeles 16710 volume 1 is 250 is the number of boxcars of widgets annually shipped from Chicago to Los Angeles and volume 2 10 000 is the net tonnage of the widgets The service type is 2 suggesting that it is an Intermodal move AB Pairs can be created in several ways and stored are fixed formatted text files with file extension abp The text file can be created using a text editor such as NotePad or TextPad or it could be an output of a ForTran or C program that extracts traffic information from a large dataset Data extraction and reformatting can also be performed by applications such as Syncsort MS Access or MS Excel Alternatively user defined functions from TRGRAPH coupled with WRITEFIX can be used to generate the AB Pairs file For efficient running of the program sort the AB Pairs file by Railroad Service Type 1f included A node and B node If all AB pairs are to be routed using the same service type this field can be excluded in the input and instead the routing type can be set in the FLOWTRAFFIC Tab 3 ALKFLOW User Manual Page 4 Flowing Traffic The main purpose of the ALKFLOW workspace is to as
5. ds Input Route Fields namely Carrier Service Type A Node and B Node and Input Flow Fields or up to 15 volume counts Enter the Starting byte and Length of each field from the ABPAIRS file in the space provided A few sample ALKFLOW User Manual Page 6 records are read from the file and displayed in the rectangular box at the bottom of the screen along with a scale to verify field positions Check the box for Valid Service Type if the file has service type information to be used in selecting routes The number of records to read per Pass can be altered if the user wishes FLOWTRAFFIC Tab 3 Routing ox Main Input Fields Routing Output ABs Input Flow Network rnw Select F Use Default SERVICE TYPE Routing F Use Routing Formula from Below E Use Routing Formula from Input File Below fT 7 Intra Family Reciprocal Operating Rights Bad Node Clean up Radius miles 2 Procedure for Absent Carriers ERROR Figure FLOWTRAFFIC Routing Tab Routing options can be specified using items on this tab The first one is the name of the network as selected in the Main tab can be changed here The next three items have check boxes and only one of those can be selected to specify the routing formula for traffic assignment The first option to use default Service Type Routing for each route based on its service type as specified in the AB Pairs file is available
6. ean up option is set and their originating and terminating volumes e Output FLOW file Optional Flow file flo is APL readable It will have volume information by link number and carrier for every link with traffic assigned to it e Output TFLOW file Optional Total Flow file tfl is APL readable It will have total link volume information for every link with non zero volume aggregated over all carriers using that link e Output miled ABPAIR file Optional text file mil will have total distance and impedance appended to each record in the Input ABPAIR file The filenames can either be typed in the text box provided or picked using a browsing window by pressing the corresponding Select button located adjacent to the text box After specifying all the filenames proceed to the other three tabs After filling out information on all tabs come back to the Main tab to execute the traffic assignment FLOWTRAFFIC Tab 2 Input Fields aio Main Input Fields Routing Output ABs Input ABPAIRS File abp Select Input Route Fields Input Flow Fields I Valid Service Type Number of Records 0 Record Length 0 Records to Read per Pass 9 Figure FLOWTRAFFIC Input Fields Tab The second tab allows the user to describe the ABPAIRS file The first item is the Input ABPAIRS file The name of the ABPAIRS file as selected in the Main tab is shown Below are two sets of fiel
7. ectional volumes appear for a given link is based on how the node numbers appear in the variable LINKS If LINKS 858 is 800 823 1 e the two nodes that define link number 858 are 800 and 823 then the directional volumes appearing first columns 2 and 4 represent traffic which moves from node 800 to node 823 Columns 3 and 5 represent traffic that in the course of its route moves from node 823 to 800 The output Flow file contains exactly one record for each link over which a specified railroad moves flowed traffic The volumes on the links usually represent many AB pairs using a common railroad and therefore the volumes on the links are actually an accumulation of AB pair volumes If two or more railroads operate over a single link the file contains separate traffic volumes separate records on every link for each railroad Total Flow File The Total Flow file is also an APL readable file and it has the extension tfl It contains total volumes over all the links in the network The file will have one record for each link that carries any traffic The function READAPL is used to read this file and bring the total flows into the TRGRAPH workspace TOTAL READAPL WB00 A sample record could be 858 60 0 2500 0 ALKFLOW User Manual Page 11 where the numbers represent link number and directional link volumes as in the Flow file the difference is that the volumes are summed for all railroads operating over the link
8. f attributes is set to 100 and can be changed by the user Executing FLOWTRAFFIC After filling out all the items in the four tabs you should return to the Main tab to run the traffic assignment process First click on the Apply button at the bottom of the screen This records all the specifications entered by the user and updates corresponding variables used in the Flow program Then click on Run to execute the program The progress bar on the right shows the status of execution Also available to the user are Reset and Cancel buttons that can be used anytime to clear all user entered parameters or exit the program respectively ALKFLOW User Manual Page 9 Outputs of FLOWTRAFFIC This section describes the contents of the output files Miled ABPAIRS Miled AB Pairs file is an optional output It is a fixed format text file and has the extension mil It contains the input AB pairs plus route information appended to each record The appended information usually is route distance in tenths of miles and impedance but can be other route specification Two sample output miled AB Pair records are 777 5164 4956 100 200 2070 3490 711 O 16434 120 250 99999 99999 The first record represents the following information 76 Railroad number 5164 On line point 4956 Off line point 100 Volume 1 200 Volume 2 2070 Distance in tenths of miles 3490 Impedance The second record is an example of an AB pair tha
9. ies of TRGRAPH This workspace is geared toward using the railway highway and waterway networks as described in TRGRAPH User Documentation This documentation assumes that the user has some knowledge of APL and TRGRAPH Loading ALKFLOW The variables and functions that constitute the APL workspace ALKFLOW are stored in a file named ALKFLOW dws in the default file directory c ptnmw in the hard disk They can be loaded to the APL session by typing the following system command from the workspace window LOAD ALKFLOW Refer to the TRGRAPH User Documentation for more information on loading workspaces ALKFLOW User Manual Page 2 Inputs to ALKFLOW The workspace requires a transportation network and a set of traffic volume data termed AB pairs The volume data should be stored on disk files with extension abp The Network When the workspace is loaded the user is shown the various available networks in the default c ptnmw folder and asked to choose one This feature allows the user to use the workspace with limited knowledge of the structure of the networks More sophisticated uses of ALKFLOW will require knowledge of network variables and structure The following are the railway network variables used in ALKFLOW Variable Name Type Dimensions Description COORD Matrix nodes 2 N row holds x y coordinates for the n node Col 1 x coordinate Col 2 y coordinate DIST Vector lin
10. ks NY element holds distance for the n link Values are miles in integer tenths of miles LINKS Matrix links 2 N row holds node pair for the n link Col 1 A node number Col 2 B node number MLC Matrix 6 links Each row holds MLC mainline code values for a service type N column holds values for the n link Service types and associated row are 1 General Merchandise 2 Intermodal 3 Coal Bulk 4 Auto Racks 5 Double stack 6 NS special codes to support custom software developed for NS OWNER Matrix n links For the n largest railroads each row holds 1 s yes and 0 s no indicating whether the railroad operates on the link See TRANS variable to identify the railroad associated with each row ALKFLOW User Manual Page 3 TRANS Vector 999 N element is a pointer to OWNER or SHORTLINE for the n railroad Values 1 999 are pointers to the k row of OWNER Values 1001 are pointers to elements of SHORTLINE Pointer is value minus 1000 Refer to the user documentation on TRGRAPH for more information on how to create and modify networks The set of traffic volume data is termed AB Pairs AB pairs usually take the form RRnum A node B node S Type Voll VolN where RRnum is the AAR railroad number e A node is the on line point for the railroad e B node is the off line point for the railroad e S Type is servi
11. of Summed Field in Output ABPAIRS File 5 Intra nodal Movement Distance tenths of miles 10 Intra nodal Movement Cost tenths of miles 80 Route Summary by Link Attribute to Append NONE y Maximum Number of Attributes 100 M Link Attribute is a Network Variable from Below MSIE gt F Link Attribute is from Input File Below Figure FLOWTRAFFIC Output A Bs Tab The final tab allows the user to specify intra nodal cost and distance and information to include in the miled AB Pairs file The first item is the Miled ABPAIR filename as given by the user in the Main tab The next two items allow the user to specify the append data The user can select DIST from the pick list or specify the name of a file that has the summed quantity to append The default value for bad routes is 99999 and can be changed by the user The next three items on this tab and their default values are Width of summed field in Miled AB Pairs file 5 Intra nodal movement Distance tenths of miles 10 Intra nodal movement Cost tenths of miles 80 The final set of output parameters lets the user specify the kind of Route Summary by Link Attribute to be appended to the miled ABpairs The options are None Flag ALKFLOW User Manual Page 8 Distance and Segments The user can pick a link attribute from a network variable or specify the name of a file with the attribute information The default value of maximum number o
12. sign traffic volumes to links on a transportation network The corresponding PTNM function which allows the user to set the parameters for the traffic assignment process and execute it is called FLOWTRAFFIC To invoke this function type FLOWTRAFFIC from the workspace editor and press Enter A user interface called ALKFLOW Control Panel appears on screen This panel has four tabs each with a set of parameter options to be specified by the user The following sections describe all the items in the four tabs FLOWTRAFFIC Tab 1 Main Lx Main Input Fields Routing Output ABs Input Flow Network mw Select Input ABPAIRS File abp Select Output LOG File log Select Output BAD File bad Select F Output FLOW File flo Select l Output TFLOW File tfl l Output Miled ABPAIR File mil Figure FLOWTRAFFIC Main Tab The user enters filenames for two input and five output files including three optional outputs The items are Input Flow Network PTNM network ntw e Input ABPAIRS files Traffic volume data as described in the preceding section of this manual abp e Output LOG file Text file log will contain a log of all the flow parameters flow summary and errors if any ALKFLOW User Manual Page 5 e Output BAD file Text file bad will contain a list of nodes from the AB pairs that were not geocoded clean up information if cl
13. t could not be flowed The quintuple 9 in the distance and impedance fields indicates this fact The zero in the on line point indicates that the Clean up process could not relocate the on line point to a point served by the Burlington Northern Santa Fe AAR number 777 within the maximum allowable distance Flow File The link flow file is in APL readable format and has the file extension flo It contains railroad specific direction link volumes The function GETVOL in TRGRAPH is used to read the flow file VOL lt 555 GETVOL WB00 where WB00 is the name of the flow file located in C ptnmw user folder The entire pathname c ptnmw user wb00 flo can be used if desired and this is required if the file is located elsewhere ALKFLOW User Manual Page 10 The above example would store traffic flows on Norfolk Southern 555 in an APL variable VOL An example of a FLOW record is as follows 858 50 0 2100 0 This record is the result of flowing AB Pairs with two volumes associated with each record The numbers represent the following 858 Link number 50 Volume 1 in one direction over link 858 0 Volume 1 in other direction over link 858 2100 Volume 2 in one direction over link 858 0 Volume 2 in other direction over link 858 GETVOL also may be used to obtain total flows over all links in all railroads by using a 0 in place of the railroad number The order in which dir
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