# OpenStreetMap road data

`osm_w-78.7_e-78.65_s35.75_n35.8_nodes.csv` and `osm_w-78.7_e-78.65_s35.75_n35.8_links.csv` are the drivable roads around NC State's two campuses, and `osm_w-78.75_e-78.55_s35.7_n35.85_nodes.csv` and `osm_w-78.75_e-78.55_s35.7_n35.85_links.csv`
those of central Raleigh, North Carolina, extracted from OpenStreetMap.

**© OpenStreetMap contributors.** The data are available under the Open Database
License (ODbL), <https://opendatacommons.org/licenses/odbl/>; see
<https://www.openstreetmap.org/copyright>. These files are a database derived from
OpenStreetMap and are distributed under the ODbL.

- Ex. 1: the box around Fitts-Woolard Hall and D. H. Hill Library (Logjam's `mapbbox`,
  xexpand 2, yexpand 0.5) is longitude, latitude -78.688, -78.657, 35.762, 35.796; `osm_roads` downloads the
  cells of its 0.05° grid that the box touches, -78.7, -78.65, 35.75, 35.8:
  10674 nodes and 18927 links.
- Ex. 3: the box around 12 drivers and 10 passengers drawn from the Census block groups
  within 3 mi of the State Capitol (seed 754; `mapbbox`, xexpand and yexpand 0.1) is
  -78.701, -78.582, 35.737, 35.821; its cells are -78.75, -78.55, 35.7, 35.85: 95699 nodes and
  176011 links.
- Downloaded from the Overpass API on 2026-10-14, through Logjam's `osm_roads`.
- Regenerated by `julia --project=. 4-networks/source/make_osm_raleigh.jl`, which keeps
  these pairs and fetches again only when one is missing.

`geocode_cache.csv` holds the longitude and latitude Nominatim, the OpenStreetMap
geocoder, returned for three Raleigh street addresses, two NC State University
buildings and the State Capitol, in the form Logjam's `loc2lonlat` reads.