CPS capacity uses 28 students per elementary homeroom and 30 per high-school homeroom. Change that assumption and every district school recolors.
Markers sit inside the school building where a city building footprint could be matched to the school — at the footprint’s furthest-from-any-wall interior point, not its centroid, because CPS wings and courtyards put centroids outside the building. Where no footprint was established the marker stays on the address point and the popup says so. An address match counts only on the school’s own side of the street (Chicago numbers one side odd, the other even), so the building across the street is never taken for the school. Footprints are the City’s 2015 snapshot, the most recent published, so a building put up since then matches whatever stood on the site. Library branches are placed the same way, and where the City’s own footprint record labels a building a library that label is used in preference to a block-wide address range — 75 of 82 branches are placed inside their building on that basis. Park District buildings run through the same matcher again, with no extra rule: CPD publishes a building point rather than a street address, so most of them start inside their own footprint and are moved to its interior point, and the ones the 2015 file has no building for stay on CPD’s point and say so. The clinics, senior centers and workforce centers are the fifth, sixth and seventh point set through that same matcher, also with no extra rule: 35 of those 50 sites are placed inside a building and the other 15 stay visibly on their address point. Because every layer is positioned by one method, the distance between a school marker and a clinic marker means the same thing as the distance between a school marker and a branch.
All 82 branches CPL publishes, drawn at one size: this layer shows where library service is, not how much of it there is. The roster carries no floor area, collection, staffing or program-space figure, and the hours shown are the usual published schedule rather than a record of any given day. A gap here is a gap in branches — school libraries and the suburban and university systems Chicagoans also use are not in this dataset.
Every building CPD records on park premises, in the five groups the inventory supports. Shape is the group and the color is the layer, because color on this map already means classroom balance. Drawn at one size: CPD publishes a floor area for 232 of 743 buildings, so sizing by it would draw three quarters of the layer at a size the source cannot support. This is an asset inventory, not a program roster — it says a building of a recorded type stands here, not what runs inside it, when it opens, or whether the pool is filled. Other types are off by default: 408 of the 743 are comfort stations, shelters, maintenance and utility buildings, and drawn together they bury the rest.
Three rosters the City publishes: the Department of Public Health’s clinic locations, split into the three types CDPH itself publishes, and the Department of Family & Support Services’ senior centers and workforce centers. 50 sites between them, drawn as a mental health clinic layer and a Community services layer that expands into the other four. Shape is the kind of site and color is the roster it comes from, the same division the park buildings follow, and all of them are drawn at one size: none of these rosters publishes a floor area, caseload, staffing level or capacity to scale a marker by.
Read the dates before reading the map. None of the three carries an operating-status field, and each describes an earlier date than the one it was last edited on — the clinics are “current as of June 2016” with rows last updated 2017-08-03, the senior centers “current as of 2011” updated 2019-03-07, and the workforce centers are labeled a “current list” whose rows have not been touched since 2011-08-21. A marker records that the City published this address as a service location, not that the service is there today. This is the rule the project already applies to CDPH’s other roster, which the health-center reconciliation uses only to corroborate addresses, never for current status. Every popup repeats it.
The mental health clinics are the clearest case. The 2016 roster has five; CDPH’s own site now lists seven. Four are still at the addresses shown here, Lawndale has moved to 1105 S. Western Ave., and two are missing from this layer altogether: Pilsen (1713 S. Ashland Ave., opened 2024) and Roseland (200 E. 115th St., reopened 2025). The article measures distances to the seven.
Three CDPH addresses carry more than one clinic — 641 W. 63rd St has a mental health clinic, an STI specialty clinic and a WIC clinic between them — and the City publishes one coordinate for all of them, so those markers sit on top of each other. Nothing is merged: turning a category off is how to see what is underneath it.
Shape is the setting, fill is access, and a × is a center that has closed. A filled circle is a center
whose published access line records it as open to the community with no restrictions; an outline is a
center open only to enrolled students, to CPS students, or to a named set of schools — or one for which
no access line is published at all, which is recorded as restricted rather than guessed at. The field is
open_to_public in sbhc_publish.csv; every popup prints the access wording behind
it verbatim, along with hours, confidence and cited sources.
Two school-linked centers are also open to the public. They stay diamonds, because on this map shape carries the setting and a filled circle would say they sit inside a school building. Their popups say they are open to the community.
Mobile units are not drawn. Two are in the data, both TCA’s; neither
has a fixed site, and HRSA registers both at their operator’s own address rather
than anywhere they park. Mapping that address would put a pin on a building
that is not a school and not where either unit goes. They stay in
sbhc_publish.csv, where the address is a field and not a claim
about location.