I would like to create a 30-minute "drive time area" (i.e. a polygon representing all of the locations that can be reached within 30 minutes, driving from a given point location), except instead of using "drive time," using "public transit time." Put another way, I'd like to create a polygon representing all of the locations that can be reached within 30 minutes, traveling via public transit, from a given point location.
My given point location is in Los Angeles, and I have the data for public transit stops and routes, but I'm not entirely certain where to go from here. I assume that I need frequency or schedule data. Any thoughts on where to find that without having to sift through dozens of individual transit schedules? Also, what to do if/when I do attain said data? Other data that I may need?
