scripts to process data for v2 of my subway deserts map
stations.geojson is the source of point geomeotries for the subway stations. (this data is hosted on DoiTT's CartoDB account)
walksheds.js takes each subway station point and runs it through OTP's isochroneAPI, getting back walksheds for 5, 7.5, and 10 minutes, it outputs {{iterator}}.geojson for each station in the /isochrones folder.
The api call looks like this:
http://{{host}}/otp/routers/default/isochrone?routeId=default&batch=true&fromPlace={{lat}},{{lng}}&date=2017/09/25&time=12:00:00&mode=WALK&cutoffSec=300&cutoffSec=450&cutoffSec=600
combine.js combines all of the separate geojson files into a single FeatureCollection called combined.geojson.
combined.geojson was uploaded to cartodb. This query unions together the 10-minute walksheds:
SELECT ST_TRANSFORM(ST_COLLECTIONEXTRACT(ST_UNION(the_geom),3),3857) as the_geom_webmercator FROM combined
Final map: https://t.co/Fyyhv4nMIE