pub fn st_buffer(
geom: &Geometry,
distance_meters: f64,
segments: usize,
) -> GeometryExpand description
ST_Buffer(geom, distance_meters) → Polygon.
Expands geometry by distance using equirectangular approximation.
- Point → 32-sided circle polygon
- LineString → buffered corridor (parallel offset + end caps)
- Polygon → expanded polygon (vertex offset outward)
Meter-to-degree conversion: Δlng = meters / (111320 * cos(lat)),
Δlat = meters / 110540. Accurate to <0.5% for ±70° latitude.