visad/src/main/java/ucar/nc2/iosp/gempak/GempakFileReader.java
protected void readKeys() throws IOException {
    if (dmLabel == null) {
      return;
    }
    keys = new DMKeys();
    // read the row keys
    int num = dmLabel.krkeys;
    List<Key> rkeys = new ArrayList<>(num);
    for (int i = 0; i < num; i++) {
      String key = DM_RSTR(dmLabel.kprkey + i);
      rkeys.add(new Key(key, i, ROW));
    }
    keys.kkrow = rkeys;
    num = dmLabel.kckeys;
    List<Key> ckeys = new ArrayList<>(num);
    for (int i = 0; i < num; i++) {
      String key = DM_RSTR(dmLabel.kpckey + i);
      ckeys.add(new Key(key, i, COL));
    }
    keys.kkcol = ckeys;
  }
protected void readKeys() throws IOException {
    if (dmLabel == null) {
      return;
    }
    keys = new DMKeys();
    // read the row keys
    int num = dmLabel.krkeys;
    List<Key> rkeys = new ArrayList<>(num);
    for (int i = 0; i < num; i++) {
      String key = DM_RSTR(dmLabel.kprkey + i);
      rkeys.add(new Key(key, i, ROW));
    }
    keys.kkrow = rkeys;
    num = dmLabel.kckeys;
    List<Key> ckeys = new ArrayList<>(num);
    for (int i = 0; i < num; i++) {
      String key = DM_RSTR(dmLabel.kpckey + i);
      ckeys.add(new Key(key, i, COL));
    }
    keys.kkcol = ckeys;
  }
Read in the row and column keys (DM_KEY)

@throws IOException problem reading file