Routeren met GTFS

Question

<\/HEAD>Ik zoek hulp bij het begrijpen hoe ik mijn openbaar vervoer reizen kan routeren via de GTFS-gegevens die ik heb geïmporteerd. <\/P> <\/P> Ik heb alle stappen in de User Guide doorlopen, evenals de online colleges. Echter, Network Analyst routeert mijn reizen alleen op mijn stratenbestand ("Streets_UseThisOne"). Wanneer ik probeer te routeren op TransitLines (wat het meest logisch lijkt bij het proberen te routeren van openbaar vervoer, ook al zijn dit slechts lijnen tussen haltes), geeft het mij een niet-doorwaadbare foutmelding. Het routeert correct op de Streets_UseThisOne-laag, maar dit is niet representatief voor waar mijn openbaar vervoer rijdt. <\/P> <\/P> Om mijn project verder toe te lichten: ik probeer historische GTFS-feeds te vergelijken met huidige GTFS-feeds. In wezen is het doel om te begrijpen hoe de reistijd in de loop der jaren is veranderd (d.w.z. OV-diensten tussen 1995 en 2005). Ik wil twee haltes kunnen nemen. Eén uit 1995 en één uit 2005 en zien hoe de reistijd is veranderd, hetzij door wegafsluitingen\/verbeteringen of door het OV-systeem dat zijn routes heeft gewijzigd. Voor zover ik begrijp, zouden deze tools mij hierbij moeten helpen, maar het lijkt erop dat ik niet de juiste resultaten kan verkrijgen. <\/P> <\/P> Mis ik iets? <\/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.