cdm/src/main/java/ucar/nc2/ft2/coverage/HorizCoordSys2D.java
private Optional<List<RangeIterator>> computeBounds(LatLonRect llbb, int horizStride) {
    synchronized (this) {
      if (edges == null) edges = new Edges();
    }
    return edges.computeBoundsExhaustive(llbb, horizStride);
  }
private Optional<List<RangeIterator>> computeBounds(LatLonRect llbb, int horizStride) {
    synchronized (this) {
      if (edges == null) edges = new Edges();
    }
    return edges.computeBoundsExhaustive(llbb, horizStride);
  }
return y, x ranges