According to the abstract of a June WA State DOT report, “This report (Sidewalk Data in King County’s Urban Growth Boundary) describes the development of geospatial sidewalk data for the King County Urban Growth Area. Prior to the development of this data set, sidewalk data in King County were limited to select jurisdictions and existed in multiple, sometimes incompatible, formats.
“Existing sidewalk data were collected from 30 of 40 jurisdictions and standardized to a geographic information system (GIS) data format that stores sidewalk coverage as attributes of King County street network centerlines. For each street segment, each side was coded as full, no, or partial sidewalk coverage. An automated coding method was developed to standardize existing data when possible. Sidewalk coverage for jurisdictions with no existing sidewalk data or with data formats incompatible with automated coding were coded manually with the aid of internet mapping resources. A total of 27 jurisdictions, including unincorporated King County, were manually coded…”
Title & Author: “Sidewalk Data in King County’s Urban Growth Boundary” by Anne Vernez Moudon, Bumjoon Kang, Jason Scully & Orion Stewart