public double size() throws GeometryException {
    return canBePolygon() ? Math.sqrt(Math.abs(area())) : canBeLine() ? length() : 0;
  }
Returns the sqrt of {@link #area()} if polygon or {@link #length()} if a line string.
planetiler-core/src/main/java/com/onthegomap/planetiler/geo/WithGeometry.java