public double hilbertProgressOnLevel(TileExtents extents) {
    return 1d * Hilbert.hilbertXYToIndex(this.z, this.x, this.y) / (1 << 2 * this.z);
  }
Returns the tile containing a latitude/longitude coordinate at a given zoom level.
planetiler-core/src/main/java/com/onthegomap/planetiler/geo/TileCoord.java