cdm/src/main/java/ucar/nc2/dataset/conv/AWIPSConvention.java
private CoordinateAxis makeTimeCoordAxisFromReference(NetcdfDataset ds, Variable timeVar, Array vals) {
    Variable refVar = ds.findVariable("reftime");
    if (refVar == null) return null;
    double refValue;
    try {
      Array refArray = refVar.read();
      refValue = refArray.getDouble(refArray.getIndex()); // get the first value
    } catch (IOException ioe) {
      return null;
    }
    if (refValue == N3iosp.NC_FILL_DOUBLE)
      return null;

    // construct the values array - make it a double to be safe
    Array dvals = Array.factory(DataType.DOUBLE, vals.getShape());
    IndexIterator diter = dvals.getIndexIterator();
    IndexIterator iiter = vals.getIndexIterator();
    while (iiter.hasNext())
      diter.setDoubleNext(iiter.getDoubleNext() + refValue); // add reftime to each of the values

    String units = ds.findAttValueIgnoreCase(refVar, CDM.UNITS, "seconds since 1970-1-1 00:00:00");
    units = normalize(units);
    String desc = "synthesized time coordinate from reftime, valtimeMINUSreftime";
    CoordinateAxis1D timeCoord = new CoordinateAxis1D(ds, null, "timeCoord", DataType.DOUBLE, "record", units, desc);

    timeCoord.setCachedData(dvals, true);

    parseInfo.format("Created Time Coordinate Axis From Reference = ");
    timeCoord.getNameAndDimensions(parseInfo, true, false);
    parseInfo.format("%n");

    return timeCoord;
  }
private CoordinateAxis makeTimeCoordAxisFromReference(NetcdfDataset ds, Variable timeVar, Array vals) {
    Variable refVar = ds.findVariable("reftime");
    if (refVar == null) return null;
    double refValue;
    try {
      Array refArray = refVar.read();
      refValue = refArray.getDouble(refArray.getIndex()); // get the first value
    } catch (IOException ioe) {
      return null;
    }
    if (refValue == N3iosp.NC_FILL_DOUBLE)
      return null;

    // construct the values array - make it a double to be safe
    Array dvals = Array.factory(DataType.DOUBLE, vals.getShape());
    IndexIterator diter = dvals.getIndexIterator();
    IndexIterator iiter = vals.getIndexIterator();
    while (iiter.hasNext())
      diter.setDoubleNext(iiter.getDoubleNext() + refValue); // add reftime to each of the values

    String units = ds.findAttValueIgnoreCase(refVar, CDM.UNITS, "seconds since 1970-1-1 00:00:00");
    units = normalize(units);
    String desc = "synthesized time coordinate from reftime, valtimeMINUSreftime";
    CoordinateAxis1D timeCoord = new CoordinateAxis1D(ds, null, "timeCoord", DataType.DOUBLE, "record", units, desc);

    timeCoord.setCachedData(dvals, true);

    parseInfo.format("Created Time Coordinate Axis From Reference = ");
    timeCoord.getNameAndDimensions(parseInfo, true, false);
    parseInfo.format("%n");

    return timeCoord;
  }
construct time coordinate from reftime variable