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

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

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_and_creating_an_OD_cost_matrix/004700000060000000/

Regards,

Jay Sandhu