Function st_dwithin

nodedb-spatial/src/predicates/distance.rs:105–120

ST_DWithin(a, b, distance_meters) — are A and B within the given distance? Optimized: uses bbox expansion pre-filter to avoid expensive exact distance computation when geometries are clearly far apart.

(a: &Geometry, b: &Geometry, distance_meters: f64)

/// Optimized: uses bbox expansion pre-filter to avoid expensive exact
/// distance computation when geometries are clearly far apart.
pub fn st_dwithin(a: &Geometry, b: &Geometry, distance_meters: f64) -> bool {
    // Fast path for points: just haversine.
    if let (Geometry::Point { coordinates: ca }, Geometry::Point { coordinates: cb }) = (a, b) {
        return haversine_distance(ca[0], ca[1], cb[0], cb[1]) <= distance_meters;
    }

    // Bbox pre-filter: expand A's bbox by distance, check if B's bbox intersects.
    let a_bb = geometry_bbox(a).expand_meters(distance_meters);
    let b_bb = geometry_bbox(b);
    if !a_bb.intersects(&b_bb) {
        return false;
    }

    // Exact check.
    st_distance(a, b) <= distance_meters
}

// ── Distance helpers ──