cdm/src/main/java/ucar/nc2/dataset/CoordinateAxis.java
public ucar.nc2.time.Calendar getCalendarFromAttribute() {
    Attribute cal = findAttribute(CF.CALENDAR);
    String s = (cal == null) ? null : cal.getStringValue();
    if (s == null) {     // default for CF and COARDS
      Attribute convention = (ncd == null) ? null : ncd.getRootGroup().findAttribute(CDM.CONVENTIONS);
      if (convention != null) {
        String hasName = convention.getStringValue();
        int version = CF1Convention.getVersion(hasName);
        if (version >= 0) {
          return Calendar.gregorian;
          //if (version < 7 ) return Calendar.gregorian;
          //if (version >= 7 ) return Calendar.proleptic_gregorian; //
        }
        if (COARDSConvention.isMine(hasName)) return Calendar.gregorian;
      }
    }
    return ucar.nc2.time.Calendar.get(s);
  }
public ucar.nc2.time.Calendar getCalendarFromAttribute() {
    Attribute cal = findAttribute(CF.CALENDAR);
    String s = (cal == null) ? null : cal.getStringValue();
    if (s == null) {     // default for CF and COARDS
      Attribute convention = (ncd == null) ? null : ncd.getRootGroup().findAttribute(CDM.CONVENTIONS);
      if (convention != null) {
        String hasName = convention.getStringValue();
        int version = CF1Convention.getVersion(hasName);
        if (version >= 0) {
          return Calendar.gregorian;
          //if (version < 7 ) return Calendar.gregorian;
          //if (version >= 7 ) return Calendar.proleptic_gregorian; //
        }
        if (COARDSConvention.isMine(hasName)) return Calendar.gregorian;
      }
    }
    return ucar.nc2.time.Calendar.get(s);
  }
needed by time coordinates