The Mayor's transport strategy sets a target that every resident of Inner London should live within a five-minute walk of a docking station. The cycle-hire team needs to report against it: for each Inner London borough, how much of its area is inside 400 m of a station, and what share of the borough that is. Two boroughs on the list barely have a station; the report has to say so with a number rather than a blank.
Return one feature per Inner London borough (inner_london = true) whose geometry is the part of the borough within 400 m of any docking station, carrying:
name — the boroughcovered_km2 — area of that covered part, km²covered_pct — covered area as a percentage of the borough's whole areaBuild the coverage as the union of 400 m buffers around every station, then clip it to each borough. The buffers overlap heavily in the centre; if you sum them instead of dissolving them, the City of London comes out several hundred percent covered.
A borough with almost no coverage is still a feature — with a very small polygon and a very small number — not a missing row.
These are where the teaching is. Read them twice.
Walk-distance coverage against a policy target is the standard accessibility report for bike-share, bus stops and public toilets alike — and 400 m is the five-minute figure most of them use.
5 scored, 0 informational
One feature per Inner London borough
18%Carries name, covered_km2 and covered_pct
18%Total covered area across Inner London
45%Result is polygons
9%Submitted in EPSG:4326
9%