;+
;Procedure: THM_LOAD_GMAG,
; thm_load_gmag, site = site, datatype = datatype, trange = trange, $
;                level = level, verbose = verbose, $
;                subtract_average = subtract_average, $
;                subtract_median = subtract_median, $
;                varname_out = varname_out, $
;                subtracted_values = subtracted_values, $
;                downloadonly = downloadonly, $
;                valid_names = valid_names
;keywords:
;  site  = Observatory name, example, thm_load_gmag, site = 'bmls', the
;          default is 'all', i.e., load all available stations . This
;          can be an array of strings, e.g., ['bmls', 'ccmv'] or a
;          single string delimited by spaces, e.g., 'bmls ccnv'
;  datatype = The type of data to be loaded, for this case, there is only
;          one option, the default value of 'mag', so this is a
;          placeholder should there be more that one data type. 'all'
;          can be passed in also, to get all variables.
;  TRANGE= (Optional) Time range of interest  (2 element array), if
;          this is not set, the default is to prompt the user. Note
;          that if the input time range is not a full day, a full
;          day's data is loaded
;  level = the level of the data, the default is 'l2', or level-2
;          data. A string (e.g., 'l2') or an integer can be used. 'all'
;          can be passed in also, to get all levels.
;  /VERBOSE : set to output some useful info
;  /SUBTRACT_AVERAGE, if set, then the average values are subtracted
;                     from the loaded variables,
;  /SUBTRACT_MEDIAN, if set, then the median values are subtracted
;                     from the loaded variables,
;  varname_out= a string array containing the tplot variable names for
;               the loaded data, useful for the following keyword:
;  subtracted_values = returns N_elements(varname_out) by 3 array
;                      containing the average or median (or 0) values
;                      subtracted from the data.
;  /downloadonly, if set, then only download the data, do not load it
;                 into variables.
;  no_download: use only files which are online locally.
;  relpathnames_all: named variable in which to return all files that are
;          required for specified timespan, probe, datatype, and level.
;          If present, no files will be downloaded, and no data will be loaded.
;  /valid_names, if set, then this will return the valid site, datatype
;                and/or level options in named variables, for example,
;
;                thm_load_gmag, site = xxx, /valid_names
;
;                will return the array of valid sites in the
;                variable xxx
; get_support_data = does nothing.  present only for consistency with other
;                load routines
;  
;Example:
;   thm_load_gmag, site = 'bmls', trange =
;   ['2007-01-22/00:00:00','2007-01-24/00:00:00']
;
;Written by: Davin Larson,   Dec 2006
; 22-jan-2007, jmm, jimm@ssl.berkeley.edu rewrote argument list, added
; keywords, 
; 1-feb-2007, jmm, added subtract_median, subtracted_value keywords
; 19-mar-2007, jmm, fixed the station list...
; $LastChangedBy: jimm $
; $LastChangedDate: 2007-05-21 16:44:54 -0700 (Mon, 21 May 2007) $
; $LastChangedRevision: 678 $
; $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/thmsoc/tags/tdas_2_02/idl/themis/ground/thm_load_gmag.pro $
;-

; processing for subracting average, median, and returning subracted value.
pro thm_load_gmag_post, sname=sitei, datatype=dtj, $
                        varcount = varcount, verbose = vb, $
                        subtract_average = subavg, $
                        subtract_median = subtract_median, $
                        varname_out = varname_out, $
                        subtracted_values = subtracted_values, _extra=_extra

;    varname = 'thg_'+lvlk+'_'+dtj+'_'+sitei
  varname = 'thg_'+dtj+'_'+sitei
  options, /default, varname, ytitle = sitei+'!cB (nT)', constant = 0.
  if varcount Eq 0 then begin
     varname_out = varname
     subtracted_values = dblarr(1, 3) ;3 field components
     varcount = varcount+1
  endif else begin
     varname_out = [varname_out, varname]
     subtracted_values = [subtracted_values, dblarr(1, 3)]
     varcount = varcount+1
  endelse

  if keyword_set(subavg) Or keyword_set(subtract_median) then begin
     get_data, varname, data = d, alim = alim
     if keyword_set(d) then begin
        lng = struct_value(alim, 'cdf.vatt.station_longitude', default = !values.f_nan)
        lat = struct_value(alim, 'cdf.vatt.station_longitude', default = !values.f_nan)
;Note 'lat' and 'lng' could be used to subtract off a model dipole
;field
        svalue = average(d.y, 1, /double, $
                         ret_median = keyword_set(subtract_median))

        d.y -= (replicate(1, n_elements(d.x)) # svalue ) ; subtract the average value
        subtracted_values[varcount-1, *] = transpose(svalue)
        store_data, varname, data = d
     endif
  endif

end

Pro thm_load_gmag, site = site, datatype = datatype, trange = trange, $
                   level = level, verbose = verbose, $
                   subtract_average = subavg, $
                   subtract_median = subtract_median, $
                   varname_out = varname_out, $
                   subtracted_values = subtracted_values, $
                   downloadonly = downloadonly, no_download=no_download, $
                   relpathnames_all=relpathnames_all, $
                   valid_names = valid_names, $
                   get_support_data=get_support_data, $
                   progobj = progobj
;                   _extra = _extra ;krb 5/4 

  if arg_present(relpathnames_all) then begin
     downloadonly=1
     no_download=1
  end

  varcount = 0

  thm_load_xxx,sname=site, datatype=datatype, trange=trange, $
               level=level, verbose=verbose, downloadonly=downloadonly, $
               no_download=no_download, relpathnames_all=relpathnames_all, $
               cdf_data=cdf_data,get_cdf_data=arg_present(cdf_data), $
               varnames=varnames, valid_names = valid_names, files=files, $
               vsnames = 'bmls ccnv chbg drby ekat fsim fsmi fykn fyts gako '+ $
               'gbay gill hots inuv kapu kian loys mcgr pgeo pina pine ptrs '+ $
               'rank rmus swno tpas ukia whit', $
               type_sname = 'site', $
               vdatatypes = 'mag', $
               get_support_data=get_support_data, $ 
               vlevels = 'l2', $
               deflevel = 'l2', $
               version = 'v01', $
               post_process_proc = 'thm_load_gmag_post', $
               subtract_average = subavg, $
               subtract_median = subtract_median, $
               varname_out = varname_out, $
               subtracted_values = subtracted_values, $
               varcount = varcount, $
               progobj = progobj, $
               _extra = _extra

end