osm-node-store

A small NodeLookup trait with a missing-means-None contract, plus a few backing strategies. Pair it with any PBF parser to build two-pass workflows.

I built this for Cosmo and OOPS - I hope it's useful for others as well!

Context

Every OSM tool that resolves way geometry from a PBF file needs an id → (lon, lat) map that can answer "I don't have this node" distinctly from "I have this node at (0, 0)."

The NodeLookup trait

The NodeLookup trait offers Option<(f64, f64)>. Missing always means None. You can use it with your choice of storage backend:

The presence bitmap lets the dense backends honor the missing-means-None contract. Sparse and memory get presence for free from their data structures.

Pick a backend by ID density, not raw dataset size — for a regional extract: sparse; dense for a planet-sized extract.

Feature Flags

• osmnodecache — optional dense-cache adapter using the osmnodecache crate plus a presence bitmap.

The crate has no default features.

osm-node-store = "0.3"
osm-node-store = { version = "0.3", features = ["osmnodecache"] }

Example

Two-pass way resolution with osmpbf. A runnable version lives at examples/two_pass_ways.rs:

cargo run --release --example two_pass_ways -- path/to/extract.osm.pbf

use osm_node_store::{
 node_store::{NodeLookup, NodeStoreWriter},
 Result,
};
use osmpbf::{Element, ElementReader};
fn main() -> Result<()> {
 let path = "great-britain-latest.osm.pbf";
 // Pass 1: stream every node into the store.
 // Sparse requires ascending IDs — PBFs from `osmium sort` satisfy this.
 let mut writer = NodeStoreWriter::new_sparse()?;
 ElementReader::from_path(path)?.for_each(|element| match element {
 Element::Node(n) => {
 writer.put_coord(n.id() as u64, (n.lon(), n.lat())).unwrap();
 }
 Element::DenseNode(n) => {
 writer.put_coord(n.id() as u64, (n.lon(), n.lat())).unwrap();
 }
 _ => {}
 })?;
 let reader = writer.finalize()?;
 // Pass 2: resolve way geometries.
 ElementReader::from_path(path)?.for_each(|element| {
 if let Element::Way(way) = element {
 for node_id in way.refs() {
 match reader.get_coord(node_id as u64) {
 Some((lon, lat)) => { /* use coord */ }
 None => { /* node not in extract */ }
 }
 }
 }
 })?;
 Ok(())
}

Development

See CONTRIBUTING.md.