function [mvals]=get_whfc_time(url);
% GET_WHFC_TIME  Reads time from an WHFC EPIC style time series file 
% and returns a structure with useful time info
% etm 3/2010  modified to use mDataset from njtools instead of using a
% DAP-enabled netcdf (requiring avery old mexnc_dap_r14)
%

nc=mDataset(url);

% Determine if uniform time base by checking if 
%      dt*(nt-1) = t(end)-t(1)
% Why use dt=(t(3)-t(1))/2 instead of dt=t(2)-t(1)?
% Good question.  Because in the first dataset I tried 
% (MYRTLEBEACH/7201adc-a.nc), t(2) was off by 1 millisecond.
% Do exact math in integers (milliseconds)

% njTBX doesn't return dimension sizes, so need to get a variable length
% and the cast to double is necessary for use with mDataset
ntimes=length(nc{'time'}(:));
d1=double(nc{'time'}(1));       % having these as double is necessary
d3=double(nc{'time'}(3));       % when netcdf-java is used.
d99=double(nc{'time'}(end));
e1=double(nc{'time2'}(1));
e3=double(nc{'time2'}(3));
e99=double(nc{'time2'}(end));

% in this program, d?=the day part of the EPIC time, e? is the parts of the
% day or "time" component (based on EPIC time2).

% round time2 values to nearest second to cover for previous sins
% in processing which have led to 1 millisecond errors 
t1=round(e1/1000)*1000;

t3=(d3-d1)*3600*24*1000+round(e3/1000)*1000;
tend=(d99-d1)*3600*24*1000+round(e99/1000)*1000;
dt=(t3-t1)/2;

% Calculate start/stop times in Matlab datenum with units=milliseconds
% EPIC is "true Julian day", where day 2440000 begins at 0000 hours, May
% 23, 1968, and datenum(1968,5,23,0,0,0) == 718941 so we need to use the 
% difference between these times
% 2440000 - 718941 == 1721059, used below

mvals.jd_start=(d1 - 1721059)+t1/3600/24/1000;
mvals.jd_stop=(d1 - 1721059)+tend/3600/24/1000;
mvals.mjd_start=(d1 - 1721059)*3600*24*1000 + t1;
mvals.mjd_stop =(d1 - 1721059)*3600*24*1000 + tend;  % fixed typo here
tot1=dt*(ntimes-1);
tot2=tend-t1;
if tot1==tot2,
    mvals.timebase_uniform=1;
    mvals.dt=dt/1000;  % dt in milliseconds
    mvals.dtms=dt;  % dt in milliseconds
else
    % check whether the mean(diff(juliandays)) is close to what's been computed, and call
    % and call it good if the numbers are close
    tt=double(nc{'time'}(:))+(double(nc{'time2'}(:))./86400000);
    dt_from_mean=mean(diff(tt))*86400000;  %msec
    if (abs(dt-dt_from_mean) > dt*.001)
        mvals.timebase_uniform=0;
    else
        mvals.timebase_uniform=1;
        mvals.dt=dt/1000;  % dt in milliseconds
        mvals.dtms=dt;
    end
end
% for the geospatial bounds we need to get the positions, not all of which
% may be there- use the variable first, and if it's not there use the
% attribute
  if isempty(nc{'lon'}(1))
    mvals.lon=nc.longitude(:);
  else
    mvals.lon=nc{'lon'}(1);
  end
  if isempty(nc{'lat'}(1))
    mvals.latmeta=nc.latitude(:);
  else
    mvals.lat=nc{'lat'}(1);
  end

close(nc);