Re: [MTAdev] Re: Real-time subway arrival estimates - we need your help

[Peter Vajko]

You are not doing anything wrong.

What you are looking at is test data, which is recorded live data, and for
various reasons, times are adjusted during playback. What this means is
that you won't be able to match these with the static GTFS.

We should have emphasized that this is not usable for matching the static
GTFS.

The real feed will have only trips ending with 00 and 50. (There still may
be trains in the static GTFS missing from the feed or the other way round
though.)

Aaron, maybe we want to post some real GTFS feed files?


> Hi Aaron,
>
> I have checked out this data and tried to correlate it with the MTA
static data from
> http://httqa.mta.info/developers/<http://httqa.mta.info/developers/> as
a comparison between realtime train status and planned service. However
I found that many trip instances in the realtime data cannot find a
match in the planned service. What I'm doing is as follows:
>
> For a trip_id, e.g. *079005_1..S03R*, I know that in static data trip_id
looks like* A20120610WKD_0790000_1..S03R, *so I check the week day of
the start date of a realtime trip, add a prefix (WKD) to the time
(079005) and get *WKD_079005_1..S03R. *Then I round up the second field
as the static plan is scheduled on a 30 second interval, which means
that the second digits can only be 00 or 50. I'm not sure if I shall
round up or down so I try every possibilities, yielding
*WKD_079000_1..S03R, **
> WKD_079050_1..S03R, **WKD_079100_1..S03R, **WKD_078950_1..S03R, etc.
*Finally
> I use these trip_id as keys to search in the MTA static data. What I can
get are partial matches between realtime trips and planned service.
>
> I wonder if I'm doing anything wrong here? or the static and realtime trips
> simply has certain amount of mismatches?
>
> Thanks!
>