joiner

Joiner joins rows from a spreadsheet, a file, an Airtable view, a Google Sheet or a DataSF dataset to areas on a map. The areas include San Francisco districts, ZIPs, neighborhoods and census tracts, H3 hexagons, Bay Area counties and ZIPs, election precincts and the districts made from them, or polygons you upload. Each area is colored by how many rows it has, or by the total, average or share of any number column. Rows with a location are drawn too. The join logic is JoinKit, shared with Selecter.

Live at https://burritojustice.github.io/joiner/. Hover the Joiner logo to see the version; CHANGELOG.md says what changed in each. Nothing is uploaded: files are read in your browser.

Loading data

Drop a file anywhere on the page, or click Load data. The dialog has Open a file… and a box for a link.

• A CSV with a column that names areas (district, ZIP, neighborhood).
• GeoJSON, or a CSV with WKT or latitude/longitude columns. These rows are drawn on the map and can be placed by location.
• Airtable. Under Airtable, paste a view link and a personal access token with data.records:read and schema.bases:read.
  • Show other tables lists every table the token can open. With a saved token, the folded heading says how far it reaches ("token: 3 bases, 12 tables").
  • Linked records are brought in as "Link: Field" columns.
  • Contact fields (email, phone, mailing address, attachments, users) are left out unless you add them back.
  • You can also load the API's records JSON as a file.
• A link to an online CSV, JSON or GeoJSON file, a DataSF or other Socrata dataset, or a Google Sheet.
  • Google Sheets must be shared with "Anyone with the link".
  • A Socrata dataset link loads every row, not just the first 1,000.
  • Other sites work only if they let other web pages read their files (CORS). If one doesn't, download the file and load that instead.
• A Joiner snapshot saved with Save: the rows and every setting, in one file you can reopen later.

Sharing. After loading a link or an Airtable view, the page address carries it (?url=… or ?airtable=…), so the page can be shared. The Airtable token is never put in the address: it stays in your browser tab until the tab closes, and whoever opens a shared page uses their own token. Snapshots contain every column you loaded, so remove names, emails and phone numbers before sharing one.

Big files. Files with tens or hundreds of thousands of rows show their progress as they read, place, count and color. A 26 MB CSV of 367,000 rows loads in about 3 seconds. Above 2,000 located rows, a file starts drawn as pinpoints; above 50,000, its points start hidden (the areas still count them).

Matching rows to areas

Match rows by picks the column, or Location (the area that contains each row's point; lines count by their midpoint). Joiner tries every column and picks the one that places the most rows; the menu shows each column's count.

• If nothing matches on the current tab and a column's name says what it holds (ZIP, district, neighborhood), Joiner switches to that set. For neighborhoods, it asks which set the names come from.
• Names are matched forgivingly:
  • Case, spaces and punctuation don't matter: "Downtown / Civic Center" matches "Downtown/Civic Center".
  • Either side of a slashed name matches it: "Treasure Island" matches "Treasure Island/YBI".
  • Names of 8 or more letters can be a letter or two off: "Outer Susnet" matches "Outer Sunset".
• A cell can list several areas, separated by commas, semicolons, pipes or line breaks. The row then counts in each of them. Clicking or hovering such a row marks all its areas, and its card names any part that isn't an area ("Not on the map: Citywide").
• The panel shows how many rows were placed and lists the values that matched no area.
• How each set matches values is set by match in sf-blocks' data/boundaries/sources.json. For example, districts accept 5, D5 or District 5.

Area sets

The tabs along the top are District, ZIP, Neighborhood (SF Find, Analysis, Planning, Realtor or Who's on First), H3 hexbins and Other. Other holds:

• Census Tracts
• Bay Area Counties and Bay Area ZIP Codes
• Election Precincts 2022, plus the US House, State Senate, Assembly and BART Board districts made from them
• Upload polygons (GeoJSON)…, to add your own areas for the session. Joiner names each area by the field that looks most like a name (not an id); pieces that share a name become one area. Name areas by, under the area list, picks another field.

Bay Area sets zoom out to show all of themselves.

H3 hexbins work anywhere, not just in SF.

• Auto picks the level whose hexagons are about 32 pixels across at the current zoom and latitude.
• The small table shows the level in use and the one on either side, each with the zooms where Auto picks it, its side length and its area.
• −½ / +½ moves the levels half a zoom later or sooner, and − / + moves one level. Fixed keeps a level at every zoom.
• Hexagons get friendly names like "Mission #82c7": the area that covers most of the hexagon, plus a short code. They're named by neighborhood, or by county once they're bigger than a neighborhood. You can also name them by any other set, or show the full H3 index.
• Clicking a hexagon pans to it without zooming, so the grid stays the same.

Colors, labels and the legend

• Color by: Count, % of total count, or the total, average or % of total of any number column.
• Area colors: Blues, Yellow–red or Blue–yellow–red. Each palette is paired with a contrasting color for the points.
• Classes:
  • Natural breaks groups similar values and splits at the biggest gaps.
  • Equal width gives each class the same range of values.
  • Quantiles gives each class about the same number of areas.
  • Log works on the logarithm of the values, which helps when a few areas are much bigger than the rest.
• Area labels: pick the lines (name, count, other fields). Label size starts at Small. Dynamic sizes labels by area, which can make big areas look like big values.
• Area outlines: Auto, Area color, Ghost, Grey, White, Black or None, in Hair, Thin, Mid or Thick widths.
• Legend: ▾ Legend folds it into one bar per layer: min and max at the ends, the median as a line and the mean as a diamond.

Basemap. Streets draw above the areas from zoom 13 (or put the areas under the basemap). Highway shields and one-way arrows are hidden. The creek fix from Block Party and Selecter hides streams and "Creek" and "Arroyo" waterways, which Protomaps tags as rivers even where they're culverted.

Features from the file

When the file has locations, Format features controls how its rows are drawn:

• Color by any column: numbers on a ramp opposite the areas' colors, text by its most common values.
• Size points by a number, with a log option.
• Size: Pinpoint, Tiny, Small, Medium, Big or Huge. Lines follow the same control. Smaller where crowded shrinks points as more of them come into view.
• Style:
  • Fill, Ring, Ghost, Black outline, White outline or Black & white.
  • Click Ring or Ghost again for a white version, which shows up on dark area colors.
• Labels: pick columns to show beside each point, from zoom 13.

The table

Table (next to Areas) shows every row, below or beside the map; the two icons switch between them.

• Sort by any column, and pin any column at the left.
• All, Area (the selected area's rows) or In view.
• Search keeps rows that contain every word you type.
• + Filter adds a filter:
  • Category columns: tick the values to keep. Each part of a list cell counts.
  • Number columns: >, < or from – to.
  • With two or more filters, All / Any says whether rows must match every filter or just one.
• Map only these makes the map count and draw just the rows that match the search and filters.
• Clicking a row pins its card, opens its area in the list, and marks all its areas on the map. Hovering the area list highlights the matching rows in the table.

Boundary layers

The polygon sets come from sf-blocks, the main copy of San Francisco's map data: one GeoJSON file per layer in data/boundaries/, plus index.json, which the map reads to build its tabs. The page reads sf-blocks' region.json for the paths and loads each file live from https://burritojustice.github.io/sf-blocks/; if that site can't be reached, it uses the copies in this repo at the same paths. data/sf-blocks.json lists the copies and the sf-blocks version they came from (hover the version number to see which the page is using). ?sfblocks=local forces the copies. Refresh them with python3 scripts/copy_sf_blocks.py ../sf-blocks.

Other names for areas ("Calle 24" for the Calle 24 Latino Cultural District, "South Bayshore" for Bayview) are in sf-blocks' data/aliases.json, by layer id, shared with Block Party. Add aliases there, not in sources.json.

The map never calls DataSF while it runs.

Layer	Tab	Join key	Features	Source
supervisor_districts	District	sup_dist (1–11)	11	DataSF cqbw-m5m3
zip_codes	ZIP	zip_code	27	DataSF srq6-hmpi
sf_find_neighborhoods	Neighborhood (default)	name	117	DataSF pty2-tcw4
analysis_neighborhoods	Neighborhood	nhood	41	DataSF p5b7-5n3h
planning_neighborhoods	Neighborhood	neighborho	37	DataSF Planning Neighborhood Groups
realtor_neighborhoods	Neighborhood	nbrhood	92	DataSF 5gzd-g9ns
wof_neighbourhoods	Neighborhood	name	116	Who's on First (84 current + 32 unverified), from sf-blocks' data/uploads/wof/
census_tracts	Other	geoid	242	DataSF sevw-6tgi

Each layer's settings are in sf-blocks' data/boundaries/sources.json:

• tab decides where the layer appears. Layers that share a tab become one menu, and "Other" puts a layer in the Other menu.
• "default": true picks the set a tab opens with.
• regional marks a layer beyond SF.
• dissolve: { from, by } builds a layer by merging another layer's polygons that share a value. That's how precincts become districts, with clean outlines.

A few precincts sit alone in their own district: one on the Bay Bridge and one near Angel Island.

Refreshing them

The boundaries are built in sf-blocks by scripts/get_layers.py (standard-library Python), from its data/boundaries/sources.json; see sf-blocks' README. It keeps the listed properties, sets each feature's id to its join key, rounds coordinates to 6 decimals, merges pieces that share a key where mergeByKey is set, sorts features by key (one per line, for readable diffs), and sets bbox to the mainland so the map doesn't zoom out to the Farallones. Then copy the new files here with python3 scripts/copy_sf_blocks.py ../sf-blocks.

Who's on First places

data/wof/ holds the San Francisco macrohoods, neighbourhoods and microhoods from Who's on First, gathered from the Spelunker's descendant list for San Francisco. Unlike the DataSF sets, WOF records a hierarchy (a microhood inside a neighbourhood inside a macrohood), which is what we need for broad names like "Sunset" or "Richmond".

File	What
places.csv	every record: id, name, placetype, status, macrohood, parent, geometry source, Spelunker and download URLs
macrohoods.geojson	4 macrohoods: Downtown, Mission District, Richmond District, Sunset District
neighbourhoods.geojson	84 current neighbourhoods (mz:is_current 1)
neighbourhoods-unverified.geojson	32 neighbourhoods with mz:is_current -1
microhoods.geojson	46 current microhoods
microhoods-unverified.geojson	49 microhoods with mz:is_current -1
raw/	the original WOF records, one file per id
ids.txt, missing.txt	ids from the Spelunker; ids not found in whosonfirst-data-admin-us

Current vs. unverified. WOF marks 84 SF neighbourhoods current (mz:is_current 1). Another 32 have mz:is_current -1: never reviewed, but not deprecated, superseded or ceased. These files are named -unverified rather than "not current" because in WOF "not current" is mz:is_current 0, the retired records. They include Excelsior, Inner and Outer Sunset, Inner and Outer Richmond, Chinatown, Bayview and Ingleside. The two sets don't overlap, and together they cover all of SF; the 84 alone cover 62% of its land. So for a full neighbourhood map, load both files. Records with mz:is_current 0 (deprecated, superseded or ceased) aren't in any layer but are listed in places.csv. None of these records set mz:is_deprecated; deprecation is in edtf:deprecated and wof:superseded_by.

node scripts/get_wof.mjs              # walk the Spelunker, download new records, rebuild outputs
node scripts/get_wof.mjs --from-ids   # skip the Spelunker; use data/wof/ids.txt
node scripts/get_wof.mjs --offline    # rebuild outputs from data/wof/raw only

Records come from GitHub (whosonfirst-data/whosonfirst-data-admin-us); places.csv also lists each record's data.whosonfirst.org URL.

Releasing

Each merged change is a new version:

1. Bump _BUILD_VERSION at the top of js/app.js (v37 → v38).
2. Add a ## v38 section at the top of CHANGELOG.md saying what changed, in terms someone using the map would notice.
3. Merge the PR. The Tag version action (.github/workflows/tag-version.yml) reads _BUILD_VERSION and tags the merge commit v38.

To tag an older commit, run the action by hand: Actions → Tag version → Run workflow, with the tag (v1) and the commit SHA.

JoinKit is pinned to one commit in index.html, and the same commit is kept in js/vendor/joinkit.js for when the CDN fails. Update both together. CLAUDE.md has the steps, and notes on how changes are built and tested.

License

AGPL-3.0 — see LICENSE.