public int minZoomWithData(String layer) {
      return IntStream.range(0, byLayer.size())
        .filter(i -> byLayer.get(i).containsKey(layer))
        .min()
        .orElse(PlanetilerConfig.MAX_MAXZOOM);
    }
Returns the minimum zoom a specific layer appears at in the tileset.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/TilesetSummaryStatistics.java