public double length() throws GeometryException {
    return Double.isNaN(length) ? (length =
      (isPoint() || canBePolygon() || canBeLine()) ? worldGeometry().getLength() : 0) : length;
  }
Returns and caches the result of {@link Geometry#getLength()} of this feature in world web mercator coordinates
where {@code 1} means the circumference of the entire planet or the distance from 85 degrees north to 85 degrees
south.
planetiler-core/src/main/java/com/onthegomap/planetiler/geo/WithGeometry.java