Enrutamiento con GTFS

Question

<\/HEAD>Estoy buscando ayuda para entender cómo enrutar mis viajes en transporte público mediante los datos GTFS que he importado. <\/P> <\/P> He seguido todos los pasos de la Guía del Usuario, así como las conferencias en línea. Sin embargo, Network Analyst solo enruta mis viajes en mi archivo de calles ("Streets_UseThisOne"). Cada vez que intento enrutar en TransitLines (que parece lo más lógico al intentar enrutar transporte público, aunque estas son solo líneas entre paradas), me da un error de no transitable. Enruta correctamente en la capa Streets_UseThisOne, pero esto no representa dónde está funcionando mi transporte público. <\/P> <\/P> Para elaborar más sobre mi proyecto: estoy intentando comparar feeds históricos de GTFS con feeds actuales de GTFS. Esencialmente, el objetivo es entender cómo ha cambiado el tiempo de viaje a lo largo de los años (es decir, servicios de tránsito entre 1995 y 2005). Me gustaría poder tomar dos paradas. Una de 1995 y otra de 2005 y ver cómo ha cambiado el tiempo de viaje, ya sea debido a cierres/mejoras en las carreteras o debido a que el sistema de tránsito cambió sus rutas. Según entiendo, estas herramientas deberían ayudarme a hacer esto, pero no parece que pueda obtener los resultados correctos. <\/P> <\/P> ¿Me estoy perdiendo de algo?<\/P><\/BODY><\/HTML>

Melinda Morang · Answer

Okay, several things going on here...

First, you should NOT expect the transit lines produced in Add GTFS to a Network Dataset to represent that actual streets or other paths taken by the transit lines in the system.  They are simply straight lines connecting stops and are meant to represent the logical connections between stops in the transit network, NOT for accurate visualization of the transit lines.  Display Route Shapes, on the other hand, specifically uses the GTFS shapes.txt file and turns those into features for visualization on the map.  Because GTFS has somewhat of a disconnection between shapes.txt and the files that represent the schedules, it's much much much easier for Add GTFS to a Network Dataset to just use straight lines.

Next, after you corrected those problems with your network dataset's settings, did you run Build Network and re-run Get Network EIDs?  Without doing those things, the changes you made aren't fully baked into the network.

Finally, the non-traversable error to be looks like one of two things:

1) Your network has some kind of restriction attribute set up, and some roads are actually restricted (non-traversable).  Perhaps the restriction is configured incorrectly.

2) You forgot to set up the layer's network location settings according to this section of the user's guide: public-transit-tools/UsersGuide.md at master · Esri/public-transit-tools · GitHub .  As a result, sometimes the input points are being located on transit lines, and bad things are happening.

TerryKarlson · Answer

Hi Melinda,

Thank you for taking the time to help me. I heeded your advice and went through the troubleshooting guide. It turns out that my Stops_Snapped2Streets were not in "override". I adjusted this setting accordingly. Additionally, I didn't have the "Use Start Time" checked in the Analysis Settings. After also changing this setting, everything else in the troubleshooting guide seemed to be similar to what I had. However, I was still receiving inaccurate results. I decided to move onto the "None of the Above" section.

I have attached pictures that will hopefully help me explain myself. The picture below is a shot of the two stops I selected from the TransitLines layer (Green lines). Note: the red lines are my Streets_UseThisOne layer. The streets somehow got broken up or pixelated when I took a screenshot. It's not this way on the computer. The orange lines are the route shape I made using the Display GTFS Route Shapes tool. I did this to compare the "solve" tool to the actual shape. The darker orange/brown color is the route from the "solve" tool.

To explain the non-traversable error I occasionally receive. Here are my results:  As you can see, I moved stop 2 slightly to the left (more on the green TransitLines layer) and I received this message when I try to "solve" the route. I moved it back for the purpose of running through the debugging process. After moving it back, it correctly solves the two stops, but the routing is off. See below:

Here you can see that it solves the route, but it takes the route in an unusual path. The spots circled in yellow are where the route does not line up with the route shape from the Display GTFS Shape tool I used. This makes me think it is still set on routing via the Streets layer.

Any ideas?

Melinda Morang · Answer

Hello Terry.

If your results seem to be never using the transit lines, please review the probably causes and solutions listed here: public-transit-tools/TroubleshootingGuide.md at master · Esri/public-transit-tools · GitHub

If that doesn't help, could you please clarify this comment?

it gives me a non-traversable error

What is the error message, and when/where did you see it? (Example: when you clicked Solve)

Regarding your ultimate goal: Yes, this should be doable.  It's probably best if you have two separate networks, one for the older data and one for the newer data.