This is an experimental tool to study "severances" for people walking. In some places, crossing a big road (a "severance") might be easy -- there's a zebra or signalized crossing right on the "desire line" where someone might want to cross. But often, a person might have to walk a few blocks to reach the nearest crossing -- and then they might have to go up or down stairs to cross on a bridge or a tunnel!

The app itself explains more: https://a-b-street.github.io/severance_snape

If you want to run this locally, you'll need npm and wasm-pack.

cd web
# Once, to install web dependencies
npm i
# Every time you modify the Rust code
npm run wasm
# To launch the local server
npm run dev

backend contains a Rust crate that gets compiled to WASM and runs in the browser. The frontend passes it OSM XML or PBF, and the Rust code builds a routable walking network in scrape.rs. lib.rs defines the network structure and also the WASM API. The API generally returns GeoJSON as a string.

web is the frontend, using Svelte and MapLibre via (shockingly) svelte-maplibre. Global variables are in stores.ts. The app is split into distinct modes.