public static ResourceUsage estimateMultipolygonGeometryUsage(Storage storage, long osmFileSize, Path path) {
    // Planet extract (62G) requires about 9.5G for way geometries
    long estimatedSize = (long) (9.5 * osmFileSize / 62);

    return new ResourceUsage("way geometry multipolygon")
      .add(path, storage, estimatedSize, "multipolygon way geometries");
  }
Estimates the resource requirements for a multipolygon geometry multimap for a given OSM input file.
planetiler-core/src/main/java/com/onthegomap/planetiler/reader/osm/OsmReader.java