function agg_sta2ncml(fid,server,prefix,stafile,mvals);
% agg_sta2ntml: Write NcML to make agg time series file CF-compliant
% Usage: agg_sta2ncml(fid,server,prefix,stafile,start,dt);
%  Inputs:
%   fid     = file id of text file *already opened for writing*
%   server  = first part of URL. For example:
%    'http://stellwagen.er.usgs.gov/cgi-bin/nph-dods/' % OPeNDAP style
%    'http://stellwagen.er.usgs.gov/'                  % HTTP style
%    '/Volumes/web/www_root/'                          % Path on Stellwagen
%   prefix  = The time series directory (next part of URL). 
%             'DATAFILES/MBAY_LT/';
%             'DATAFILES/MYRTLEBEACH/';
%   stafile = name of NetCDF file 
%             '7201adc-a.nc';
%   start   = Matlab datenum, but in milliseconds (use double precision!)
%   dt      = time interval in days (use double precision!)

% Rich Signell (rsignell@usgs.gov)
% Notes on making our Time Series Data CF-compliant:  
%   Time: Our time series data use non CF-compliant time convention,
%   with "time" variable containing Julian days and "time2" containing
%   milliseconds since midnight.  To make these CF-compliant, we use
%   NcML to construct a double precision time vector in Modified Julian Day,
%   one of the few internationally recognized time conventions that starts
%   at midnight. (See http://tycho.usno.navy.mil/mjd.html for more info.)
%
%   We specify MJD as long variable type in milliseconds, which will give us accuracy of: 
%   - better than 3.0e-5 milliseconds until August 31, 2132 and 
%   - better than 3.0e-4 milliseconds until October 12, 4596!
%     
start=mvals.mjd_start; % matlab datenum
dt=mvals.dtms; % convert dt (seconds => days)

% Find the netcdf variable name for temperature by finding
% which long_name attribute starts with 'TEMPERATURE'.  This could be 
% done also by finding variable names matching 'T_20','T_28', etc. 
% 
% Whatever temperature variable name we find, we rename
% the temperature variable with the name 'temp' using NcML so
% that we can aggregate

for i=1:length(mvals.varnames);
  if length(mvals.long_names{i})>=11,
    if strmatch(upper(mvals.long_names{i}(1:11)),'TEMPERATURE'),
        var=mvals.varnames{i};
    end
  end
end
   
start=(start-3600*24*1000*datenum(1858,11,17,0,0,0));  % convert datenum to MJD 
location=[server prefix stafile];

fprintf(fid,'<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2" location="%s">\n',location);
fprintf(fid,'<variable name="time" shape="time" type="long">\n');
fprintf(fid,'  <attribute name="units" value="milliseconds since 1858-11-17 00:00:00 UTC"/>\n');
fprintf(fid,'  <attribute name="long_name" value="Modified Julian Day"/>\n');
fprintf(fid,'  <values start="%.0f" increment="%.0f"/>\n',start,dt);
fprintf(fid,'</variable>\n');
fprintf(fid,'<variable name="temp" orgName="%s">\n',var);
fprintf(fid,'<attribute name="standard_name" type="String" value="sea_water_temperature" />\n');
fprintf(fid,'</variable>\n');
fprintf(fid,'</netcdf>\n');