public void writeHeader(
      List<ucar.unidata.geoloc.Station> stns,
      List<VariableSimpleIF> vars,
      int nprofiles,
      String altVarName)
      throws IOException {
    createGlobalAttributes();
    createStations(stns);
    createProfiles(nprofiles);

    // dummys, update in finish()
    ncfile.addGlobalAttribute("zaxis_coordinate", altVarName);
    ncfile.addGlobalAttribute("time_coverage_start", dateFormatter.toDateTimeStringISO(new Date()));
    ncfile.addGlobalAttribute("time_coverage_end", dateFormatter.toDateTimeStringISO(new Date()));

    createDataVariables(vars);

    ncfile.create(); // done with define mode

    writeStationData(stns); // write out the station info

    // now write the observations
    if (!(Boolean) ncfile.sendIospMessage(NetcdfFile.IOSP_MESSAGE_ADD_RECORD_STRUCTURE))
      throw new IllegalStateException("can't add record variable");
  }
 private void createGlobalAttributes() {
   ncfile.addGlobalAttribute("Conventions", "Unidata Observation Dataset v1.0");
   ncfile.addGlobalAttribute("cdm_datatype", "Profile");
   ncfile.addGlobalAttribute("title", title);
   ncfile.addGlobalAttribute("desc", "Extracted by THREDDS/Netcdf Subset Service");
   /* ncfile.addGlobalAttribute("observationDimension", recordDimName);
   ncfile.addGlobalAttribute("stationDimension", stationDimName);
   ncfile.addGlobalAttribute("latitude_coordinate", latName);
   ncfile.addGlobalAttribute("longitude_coordinate", lonName);
   ncfile.addGlobalAttribute("time_coordinate", timeName); */
 }
  private void createStations(List<ucar.unidata.geoloc.Station> stnList) throws IOException {
    int nstns = stnList.size();

    // see if there's altitude, wmoId for any stations
    for (int i = 0; i < nstns; i++) {
      ucar.unidata.geoloc.Station stn = stnList.get(i);

      // if (!Double.isNaN(stn.getAltitude()))
      //  useAlt = true;
      if ((stn.getWmoId() != null) && (stn.getWmoId().trim().length() > 0)) useWmoId = true;
    }

    /* if (useAlt)
    ncfile.addGlobalAttribute("altitude_coordinate", altName); */

    // find string lengths
    for (int i = 0; i < nstns; i++) {
      ucar.unidata.geoloc.Station station = stnList.get(i);
      name_strlen = Math.max(name_strlen, station.getName().length());
      desc_strlen = Math.max(desc_strlen, station.getDescription().length());
      if (useWmoId) wmo_strlen = Math.max(wmo_strlen, station.getName().length());
    }

    LatLonRect llbb = getBoundingBox(stnList);
    ncfile.addGlobalAttribute(
        "geospatial_lat_min", Double.toString(llbb.getLowerLeftPoint().getLatitude()));
    ncfile.addGlobalAttribute(
        "geospatial_lat_max", Double.toString(llbb.getUpperRightPoint().getLatitude()));
    ncfile.addGlobalAttribute(
        "geospatial_lon_min", Double.toString(llbb.getLowerLeftPoint().getLongitude()));
    ncfile.addGlobalAttribute(
        "geospatial_lon_max", Double.toString(llbb.getUpperRightPoint().getLongitude()));

    // add the dimensions
    Dimension recordDim = ncfile.addUnlimitedDimension(recordDimName);
    recordDims.add(recordDim);

    Dimension stationDim = ncfile.addDimension(stationDimName, nstns);
    stationDims.add(stationDim);

    // add the station Variables using the station dimension
    Variable v = ncfile.addVariable(latName, DataType.DOUBLE, stationDimName);
    ncfile.addVariableAttribute(v, new Attribute("units", "degrees_north"));
    ncfile.addVariableAttribute(v, new Attribute("long_name", "station latitude"));

    v = ncfile.addVariable(lonName, DataType.DOUBLE, stationDimName);
    ncfile.addVariableAttribute(v, new Attribute("units", "degrees_east"));
    ncfile.addVariableAttribute(v, new Attribute("long_name", "station longitude"));

    if (useAlt) {
      v = ncfile.addVariable(altName, DataType.DOUBLE, stationDimName);
      ncfile.addVariableAttribute(v, new Attribute("units", "meters"));
      ncfile.addVariableAttribute(v, new Attribute("long_name", "station altitude"));
    }

    v = ncfile.addStringVariable(idName, stationDims, name_strlen);
    ncfile.addVariableAttribute(v, new Attribute("long_name", "station identifier"));

    v = ncfile.addStringVariable(descName, stationDims, desc_strlen);
    ncfile.addVariableAttribute(v, new Attribute("long_name", "station description"));

    if (useWmoId) {
      v = ncfile.addStringVariable(wmoName, stationDims, wmo_strlen);
      ncfile.addVariableAttribute(v, new Attribute("long_name", "station WMO id"));
    }

    v = ncfile.addVariable(numProfilesName, DataType.INT, stationDimName);
    ncfile.addVariableAttribute(
        v, new Attribute("long_name", "number of profiles in linked list for this station"));

    v = ncfile.addVariable(firstProfileName, DataType.INT, stationDimName);
    ncfile.addVariableAttribute(
        v, new Attribute("long_name", "index of first profile in linked list for this station"));
  }