Zoom in and the activity icons appear on their own. Click a park for everything it holds. Turn on an activity to map every place you can do it citywide. District lines do not limit the results, so if the nearest court is a district over, it still comes up first.
Park shapes come from the NYC Parks Properties dataset, 2,058 properties citywide. District lines are the Department of City Planning community district boundaries.
Activity locations come from four NYC Parks datasets on NYC Open Data: Athletic Facilities, Pools, SkateParks, and Dog Runs. Each is matched to its community district by mapped boundary rather than by the agency's own district field, which contains errors.
Lap Swimming covers Olympic, Intermediate, and Large pools. Wading and mini pools are listed separately. Pools are marked indoor or outdoor.
NYC Parks records cover the parks it runs. Nine major parks are run by someone else, so their courts and fields never reach the agency data: Brooklyn Bridge Park, Hudson River Park, Battery Park City, The Battery, Governors Island, Bryant Park, Domino Park, Riverbank State Park and Roosevelt Island. Those are filled in here from OpenStreetMap and marked with who runs them. School gyms, private clubs, and YMCA facilities are still not covered.