About Me!
This blog is about my musings and thoughts. I hope you find it useful, at most, and entertaining, at least.
Other Pages
Presence Elsewhere
Calculating Service Area, Part 4: Next Steps
Date: 2019-01-27
Tags: postgis postgres transit census
In Part 1 we talked about the project and got some of the tools and data we need to start. A quick reminder of our motivation: to figure out the percentage area and population the county transit agency serves by using a "walkshed".
Parts
- Part 1: Introduction and Setup
- Part 2: Defining the Walkshed
- Part 3: Demographics
- Part 4: Next Steps
Walkshed
There are two changes I should make to the walkshed calculation before I dig into per-route statistics: (1) excluding interstates and (2) light rail and busways stations should have a half mile walkshed. I don't believe they made a difference at the county level; once I redo the calculations I'll come back to see if I have to eat those words.
More In-Depth Demographic Analysis
Since we have all of the census data, all of the route data, and we broke our walkshed down by stop it'd be quite easy to look at the service area as a whole, and routes in particular against other socio-economic indicators.
Also, more interestingly, who isn't being served?
Filter Walkshed by Reliable Transit
I'd love to look at what the walkshed is when only stops that are served more frequently than every 30 min mid-day is included. Another alternative would be late at night, or weekends. Essentially, what's the service area that you could do a good deal in without having to get into a car?
Build a web-based tool to export this data
I would love to make this data more usable and accessible. I previously made a little tool using python, mapnik, and a file from GDAL2Tiles. I'd like to explore if QGIS' "save project to database" functionality could be used (i.e. mangled, forced, hacked?) to do this more cleanly.
Isochron / Isotrip maps
I've been wanting to build an application where you could pick a location and it'd generate two (interactive) maps of all other stops: an isochron map showing how long it'd take to get anywhere else (and that has 15-min isochron lines showing the boundry of how long it takes to get how far) and an isotrip map showing how many trips/transfers it'd take to get to the other stop, with similar isotrip lines.
Create Subject Tables
The Access DBs also contain information on what all the fields mean and which
subject tables they belong to. We can extract it with the mdb-export tool.
mdb-export SF1_Access2003.mdb data_field_descriptors > data_field_descriptors.csv