Trying to incorporate a GTFS route sequence into service area analysis layer

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11-15-2010 02:01 PM
AndrewJoseph
New Contributor
Hello all,

I am working on a research project that looks at the maximum distance a person can travel by bus from a given intersection within one hour at specified time intervals, such as 4:00 PM.

To do this I have created a route shapefile and stop points from the GTFS (Google or General Transit Feed Specification) data

For each stop on each trip along each route I have the arrival time and departure times of the buses, which I have standardized into impedances by calculating the hours elapsed since the beginning of the interval. My problem is that I am unsure of how to restrict transfers to trips that have not already occured (i.e. the total accumulated time impedance < departure time of trip) and then how to make the solver adhere to the trip sequences once a transfer has occured.

This problem has been stumping me all week; any help would be greatly appreciated!

Thanks,

Andrew
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5 Replies
JaySandhu
Esri Regular Contributor
Service Area finds the area upto a specified break value from one or more locations.

You say:
"My problem is that I am unsure of how to restrict transfers to trips that have not already occured (i.e. the total accumulated time impedance < departure time of trip) and then how to make the solver adhere to the trip sequences once a transfer has occured."

I have tried to understand what this means but cannot. If you want to explain it more perhaps someone can provide a way to solve it.


As far as:
"I am working on a research project that looks at the maximum distance a person can travel by bus from a given intersection within one hour at specified time intervals, such as 4:00 PM."

If you take a look at the Network Analyst tutorial data, the Paris dataset has a pedestrian walk time attribute that lets you model the travel on metro plus walk on roads. You can solve a service area on that data from any location and see how far you can get for a given break value. Is this what you are trying to achieve? The dataset is used in the following tutorial:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Exercise_5_Calculating_service_areas_a...


Regards,
Jay Sandhu
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AndrewJoseph
New Contributor
I'm sorry for not properly explaining the problem, I have attached a pdf in two zip files that addresses the topic in greater depth.

If you take a look at the Network Analyst tutorial data, the Paris dataset has a pedestrian walk time attribute that lets you model the travel on metro plus walk on roads. You can solve a service area on that data from any location and see how far you can get for a given break value. Is this what you are trying to achieve? The dataset is used in the following tutorial:
http://help.arcgis.com/en/arcgisdesk...0000060000000/


I have worked through that tutorial already trying to solve this problem and have unfortunately found that my problem is more complex than the topics discussed in the tutorial.

Thanks,

Andrew
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MichaelLachman1
New Contributor
Bump.  Andrew, were you ever able to figure out a solution to this problem?  I'm working on a similar study, though not using a GTFS feed as the source.
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MelindaMorang1
New Contributor III
Hi everyone.  I've been working on this exact same problem and have developed a tool that allows you to calculate walking/transit service areas using Network Analyst and GTFS data.  Check out http://transit.melindamorang.com.  A beta version of the tool will be available for download within the next few weeks, and I'd love to get your feedback and ideas for improvement.
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MelindaMorang
Esri Regular Contributor
Hello everyone.  I just wanted to let you know about a new prototype tool from Esri's Network Analyst team which allows you to add GTFS public transit data directly to a network dataset.  You can use this network dataset with the Network Analyst tools to run time-aware analyses that incorporate the transit schedules.
You can download the toolset and instructions here:
http://www.arcgis.com/home/item.html?id=0fa52a75d9ba4abcad6b88bb6285fae1
Please do not hesitate to contact me at mmorang@esri.com with questions or comments about this toolset.
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