Glossary

Census block: the smallest area the US Census publishes, usually one city block. Close computes travel times from every block. See The data.

GEOID: the identifier for a census geography. A block GEOID is 15 digits; a place GEOID (a city or town, from GET /v1/places) is shorter. Block routes take a block GEOID; place_blocks takes a place GEOID.

Census place: an incorporated city or town. Look one up by name with GET /v1/places to get its GEOID and centre point.

Mode: how you travel, walk, bike, or transit. Block, point, and POI routes report the mode as a string label; the areal routes report it as a numeric mode_id (join GET /v1/meta/modes to label it).

Destination type: a category of amenity, identified by a numeric type id. A leaf type is one amenity (grocery stores); a parent type expands to several leaves. See Destination types.

Travel time: minutes to the nearest amenity, capped at 30. A missing (block, type) row means the amenity is not reachable within the cap, not that it is zero.

Isochrone: the area reachable within a time budget, as contours (rings at each minute threshold). See Isochrones.

Catchment / walkshed: the set of blocks that can reach a given amenity within a time budget (poi_catchment). “Walkshed” is a catchment for the walking mode.

Cursor: an opaque marker for the next page of a list result. Pass the next_cursor from one page to get the next; never construct one yourself. See Pagination.

ETag / 304: a version tag on a response. Send it back as If-None-Match; if nothing changed you get a free 304 Not Modified. See Conditional requests.

Token: the unit of metering, one per returned row, minimum one per request; isochrones cost 10 per contour. See Metering.

Vintage: the version of a dataset component (road network, transit, POIs, blocks, parks). Read GET /v1/meta/vintage to see how current each one is.