cdm/src/main/java/ucar/nc2/dataset/CoordSysBuilder.java
protected void addCoordinateVariable(Dimension dim, VarProcess vp) {
    List<VarProcess> list = coordVarMap.get(dim);
    if (list == null) {
      list = new ArrayList<>();
      coordVarMap.put(dim, list);
    }
    if (!list.contains(vp))
      list.add(vp);
  }
protected void addCoordinateVariable(Dimension dim, VarProcess vp) {
    List<VarProcess> list = coordVarMap.get(dim);
    if (list == null) {
      list = new ArrayList<>();
      coordVarMap.put(dim, list);
    }
    if (!list.contains(vp))
      list.add(vp);
  }
track coordinate variables