function readmud, FilePath, FromSecond, ToSecond, sample_rate


;FilePath='c:\LYR_2007_01.MUD'
;FromSecond = long(long(3600) * 24)
;ToSecond = long(long(3600) * 24 * 2)

; open the MUD file:
dat_fh = 1
openr, dat_fh, filepath, /get_lun

; read header
FileFlag = bytarr(4)
NumChannels = 0
SampleRate = 0
SampleSize = 0
StartYear = 0
StartMonth = 0
StartDay = 0
StationName = bytarr(4)
NumSeconds = long(0)
Reserved1 = long(0)
Reserved2 = long(0)

readu, dat_fh, FileFlag
readu, dat_fh, NumChannels
readu, dat_fh, SampleRate
readu, dat_fh, SampleSize
readu, dat_fh, StartYear
readu, dat_fh, StartMonth
readu, dat_fh, StartDay
readu, dat_fh, StationName
readu, dat_fh, NumSeconds
readu, dat_fh, Reserved1
readu, dat_fh, Reserved2

; set sample buffer size
SampleBufferSize = SampleRate * SampleSize / 8

; allocate data array
Data_Array  = fltarr(2, (long(ToSecond)-long(FromSecond)) * sample_rate)

; allocate temp buffer
Buffer_Array = intarr(10, 2)

; move to the 1st data position
Offset = long(32)
Offset = Offset + FromSecond * (4 + SampleBufferSize * NumChannels)
POINT_LUN, dat_fh, Offset

; read samples
Second = long(0)
FOR n = long(0), long(ToSecond)-long(FromSecond)-1 DO BEGIN
    readu, dat_fh, Second

    ; read 10-sample chunk of 2 channels
    readu, dat_fh, Buffer_Array

    ; assign the samples to the data array
    FOR m = 0, 9 DO BEGIN
        Data_Array(0, n * 10 + m) = (Buffer_Array(m, 0) + 2048.0) / 4096.0 * 20.0 - 10.0;
        Data_Array(1, n * 10 + m) = (Buffer_Array(m, 1) + 2048.0) / 4096.0 * 20.0 - 10.0;
    ENDFOR
ENDFOR

; close the file
free_lun, dat_fh

return, Data_Array
end




;Color bar added. 4/24/2008  Hyomin Kim
;Modified to incorporate UNH web service. 4/24/2008  Hyomin Kim
;A code to generate survey plots from the UNH ULF data which are saved in MUD format. 4/13/2007  Hyojin Kim

;example: web_plot, database_dir, '20161031', '000000', '240000',
;plot_dir, 'ps', '1000000', 1, 2048, 200, 0.2, 0, 1
pro web_plot, $
   database_dir, $
   date, $
   start_time, $
   end_time, $
   plot_dir, $
   file_format, $
   stations, $
   maxfreq, $
   nfft, $
   step, $
   max_B_field, $
   f_low, $
   f_high

;determine which stations were requested from stations string
NAL = 0
LYR = 0
HOR = 0
SDY = 0
POK = 0
IQA = 0
ISR = 0
if strmid(stations, 0, 1) eq '1' then NAL = 1
if strmid(stations, 1, 1) eq '1' then LYR = 1
if strmid(stations, 2, 1) eq '1' then HOR = 1
if strmid(stations, 3, 1) eq '1' then SDY = 1
if strmid(stations, 4, 1) eq '1' then POK = 1
if strmid(stations, 5, 1) eq '1' then IQA = 1
if strmid(stations, 6, 1) eq '1' then ISR = 1

f_low         = 0             ;Hz
f_high        = maxfreq   ;Hz


;====== Create station names for file name
station_names = strarr(1)
if NAL eq 1 then begin
	station_names = 'N'
endif
if LYR eq 1 then begin
	station_names = station_names + 'L'
endif
if HOR eq 1 then begin
	station_names = station_names + 'H'
endif
if SDY eq 1 then begin
	station_names = station_names + 'S'
endif
if POK eq 1 then begin
	station_names = station_names + 'P'
endif
if IQA eq 1 then begin
	station_names = station_names + 'I'
endif
if ISR eq 1 then begin
	station_names = station_names + 'R'
endif



;====== Extracting the date and time
yyyy         = strmid(date, 0, 4)
mm        	 = strmid(date, 4, 2)
dd           = strmid(date, 6, 2)
start_hour   = strmid(start_time, 0, 2)
start_min    = strmid(start_time, 2, 2)
start_second = strmid(start_time, 4, 2)
end_hour     = strmid(end_time, 0, 2)
end_min      = strmid(end_time, 2, 2)
end_second   = strmid(end_time, 4, 2)
spm          = 60.0
mph          = 60.0
hpd          = 24.0
sph          = 3600.0
start_time_sec = start_hour*sph+start_min*mph+start_second  ;start time in seconds
end_time_sec   = end_hour*sph+end_min*mph+end_second       ;end time in seconds
duration_sec   = end_time_sec - start_time_sec
duration       = duration_sec/sph   ;in decimal hour.

ulf_tick_labels, double(start_time_sec), double(end_time_sec), xtick_count, tick_values, xtick_labels

;====== Specify MUD sources
database_path_NAL = database_dir + '/NAL_' + strtrim(string(yyyy), 1) + '_' + strtrim(string(mm), 1) + '.MUD'
database_path_LYR = database_dir + '/LYR_' + strtrim(string(yyyy), 1) + '_' + strtrim(string(mm), 1) + '.MUD'
database_path_HOR = database_dir + '/HOR_' + strtrim(string(yyyy), 1) + '_' + strtrim(string(mm), 1) + '.MUD'
database_path_SDY = database_dir + '/SDY_' + strtrim(string(yyyy), 1) + '_' + strtrim(string(mm), 1) + '.MUD'
database_path_POK = database_dir + '/POK_' + strtrim(string(yyyy), 1) + '_' + strtrim(string(mm), 1) + '.MUD'
database_path_IQA = database_dir + '/IQA_' + strtrim(string(yyyy), 1) + '_' + strtrim(string(mm), 1) + '.MUD'
database_path_ISR = database_dir + '/ISR_' + strtrim(string(yyyy), 1) + '_' + strtrim(string(mm), 1) + '.MUD'


;====== Initialize data variables
sample_rate     = 10.    ;Hz
period          = 1./sample_rate   ;sec
datacount       = long(duration * sph * sample_rate)
times           = findgen(datacount) * period/sph
data_array_NAL  = dblarr(3, datacount)
data_array_LYR  = dblarr(3, datacount)
data_array_HOR  = dblarr(3, datacount)
data_array_SDY  = dblarr(3, datacount)
data_array_POK  = dblarr(3, datacount)
data_array_IQA  = dblarr(3, datacount)
data_array_ISR  = dblarr(3, datacount)

;====== Set up parameters for FFT process
nfft         = nfft             ;number of points per fft: 1024 -> 0.47 mHz
step         = step  ;step size between fft's (secs) (YOU CAN SPECIFY THE STEP SIZE FOR RESOLUTION, HYOJIN)
missing      = double(9999999.0)  ;missing data value
yminor_count = 5
;system_gain  = 4.43               ;system gain = 4.43 V/(nT*Hz)--> applies only to UNH ULF system
max_B_field  = max_B_field               ;nT*Hz (nT/s)
maxfreq      = maxfreq                 ;highest frequency plotted, in Hz
;pstart       = 0 / sph         ;---> fix this (Hyomin 4/1/08)
pstart       = start_time_sec / sph
nsum_value   = duration * 5       ;for reduction of data size of time series plot
f_nyquist    = sample_rate/2     ;Hz
f_low        = f_low             ;Hz
f_high       = f_high              ;Hz
coeff       = digital_filter(f_low/f_nyquist, f_high/f_nyquist, 100, 50)
;Determine spectral array size and number of arrays for spectral images
skip          = round(step / period)
ncols         = round((duration * spm * mph) / period)
if ((ncols mod skip) ne 0) then print,'Error in step size!!!!!!!'
print, 'skip, period, ncols ', skip, period, ncols
ncols         = ncols/skip
hzperbin      = 1/ (nfft * period)
nrows         = round(maxfreq / hzperbin)
maxfreq_calc  = hzperbin * nrows
spectra       = dblarr(ncols,nrows)
help, spectra

;====== Read in data (stored in database) from the stations selected to be plotted
no_stations   = NAL + LYR + HOR + SDY + POK + IQA + ISR
plot_array_Bx = dblarr(no_stations*2, datacount)
plot_array_By = dblarr(no_stations*2, datacount)
station_code  = strarr(no_stations)
fromSecond    = (long(dd) - 1) * 86400 + (long(start_hour)*3600) + (long(start_min)*60) + start_second
toSecond 	  = long(fromSecond) + long(duration_sec)
system_gain   = 4.43  ;system gain = 4.43 V/(nT*Hz) --> applies only to UNH ULF system
station_index = 0

if NAL eq 1 then begin
	file_array_NAL = readmud(database_path_NAL, fromSecond, toSecond, sample_rate)
	temp_array_NAL 	    = reform(file_array_NAL(0,*))
	file_array_NAL(0,*) = convol(temp_array_NAL, coeff) ;digital filtering
	temp_array_NAL 		= reform(file_array_NAL(1,*))
	file_array_NAL(1,*) = convol(temp_array_NAL, coeff) ;digital filtering
	plot_array_Bx(station_index,*)    = times
	plot_array_Bx(station_index+1, *) = file_array_NAL(0, *)/system_gain ;x signal in terms of nT
	plot_array_By(station_index,*)    = times
	plot_array_By(station_index+1, *) = file_array_NAL(1, *)/system_gain ;y signal in terms of nT
	;->Change data in V (original data format) to in nT by dividing by the system gain ->applies only to UNH ULF system.
	station_code(station_index/2)     = 'NAL'
	station_index = station_index + 2
endif

if LYR eq 1 then begin
	file_array_LYR = readmud(database_path_LYR, fromSecond, toSecond, sample_rate)
	temp_array_LYR 		= reform(file_array_LYR(0,*))
	file_array_LYR(0,*) = convol(temp_array_LYR, coeff) ;digital filtering
	temp_array_LYR 		= reform(file_array_LYR(1,*))
	file_array_LYR(1,*) = convol(temp_array_LYR, coeff) ;digital filtering
  	plot_array_Bx(station_index,*)    = times
	plot_array_Bx(station_index+1, *) = file_array_LYR(0, *)/system_gain ;x signal in terms of nT
	plot_array_By(station_index,*)    = times
	plot_array_By(station_index+1, *) = file_array_LYR(1, *)/system_gain ;y signal in terms of nT
    ;->Change data in V (original data format) to in nT by dividing by the system gain ->applies only to UNH ULF system.
	station_code(station_index/2)  = 'LYR'
	station_index = station_index + 2
endif

if HOR eq 1 then begin
	file_array_HOR = readmud(database_path_HOR, fromSecond, toSecond, sample_rate)
	temp_array_HOR 		= reform(file_array_HOR(0,*))
	file_array_HOR(0,*) = convol(temp_array_HOR, coeff) ;digital filtering
	temp_array_HOR 		= reform(file_array_HOR(1,*))
	file_array_HOR(1,*) = convol(temp_array_HOR, coeff) ;digital filtering
  	plot_array_Bx(station_index,*)    = times
	plot_array_Bx(station_index+1, *) = file_array_HOR(0, *)/system_gain ;x signal in terms of nT
	plot_array_By(station_index,*)    = times
	plot_array_By(station_index+1, *) = file_array_HOR(1, *)/system_gain ;y signal in terms of nT
    ;->Change data in V (original data format) to in nT by dividing by the system gain ->applies only to UNH ULF system.
	station_code(station_index/2)  = 'HOR'
	station_index = station_index + 2
endif

if SDY eq 1 then begin
	file_array_SDY = readmud(database_path_SDY, fromSecond, toSecond, sample_rate)
	temp_array_SDY 		= reform(file_array_SDY(0,*))
	file_array_SDY(0,*) = convol(temp_array_SDY, coeff) ;digital filtering
	temp_array_SDY 		= reform(file_array_SDY(1,*))
	file_array_SDY(1,*) = convol(temp_array_SDY, coeff) ;digital filtering
  	plot_array_Bx(station_index,*)    = times
	plot_array_Bx(station_index+1, *) = file_array_SDY(0, *)/system_gain ;x signal in terms of nT
	plot_array_By(station_index,*)    = times
	plot_array_By(station_index+1, *) = file_array_SDY(1, *)/system_gain ;y signal in terms of nT
    ;->Change data in V (original data format) to in nT by dividing by the system gain ->applies only to UNH ULF system.
	station_code(station_index/2)  = 'SDY'
	station_index = station_index + 2
endif

if POK eq 1 then begin
	file_array_POK = readmud(database_path_POK, fromSecond, toSecond, sample_rate)
	temp_array_POK 		= reform(file_array_POK(0,*))
	file_array_POK(0,*) = convol(temp_array_POK, coeff) ;digital filtering
	temp_array_POK 		= reform(file_array_POK(1,*))
	file_array_POK(1,*) = convol(temp_array_POK, coeff) ;digital filtering
  	plot_array_Bx(station_index,*)    = times
	plot_array_Bx(station_index+1, *) = file_array_POK(0, *)/system_gain ;x signal in terms of nT
	plot_array_By(station_index,*)    = times
	plot_array_By(station_index+1, *) = file_array_POK(1, *)/system_gain ;y signal in terms of nT
    ;->Change data in V (original data format) to in nT by dividing by the system gain ->applies only to UNH ULF system.
	station_code(station_index/2)  = 'POK'
	station_index = station_index + 2
endif

if IQA eq 1 then begin
	file_array_IQA = readmud(database_path_IQA, fromSecond, toSecond, sample_rate)
	temp_array_IQA 		= reform(file_array_IQA(0,*))
	file_array_IQA(0,*) = convol(temp_array_IQA, coeff) ;digital filtering
	temp_array_IQA 		= reform(file_array_IQA(1,*))
	file_array_IQA(1,*) = convol(temp_array_IQA, coeff) ;digital filtering
  	plot_array_Bx(station_index,*)    = times
	plot_array_Bx(station_index+1, *) = file_array_IQA(0, *)/system_gain ;x signal in terms of nT
	plot_array_By(station_index,*)    = times
	plot_array_By(station_index+1, *) = file_array_IQA(1, *)/system_gain ;y signal in terms of nT
    ;->Change data in V (original data format) to in nT by dividing by the system gain ->applies only to UNH ULF system.
	station_code(station_index/2)  = 'IQA'
	station_index = station_index + 2
endif

if ISR eq 1 then begin
	file_array_ISR = readmud(database_path_ISR, fromSecond, toSecond, sample_rate)
	temp_array_ISR 		= reform(file_array_ISR(0,*))
	file_array_ISR(0,*) = convol(temp_array_ISR, coeff) ;digital filtering
	temp_array_ISR 		= reform(file_array_ISR(1,*))
	file_array_ISR(1,*) = convol(temp_array_ISR, coeff) ;digital filtering
  	plot_array_Bx(station_index,*)    = times
	plot_array_Bx(station_index+1, *) = file_array_ISR(0, *)/system_gain ;x signal in terms of nT
	plot_array_By(station_index,*)    = times
	plot_array_By(station_index+1, *) = file_array_ISR(1, *)/system_gain ;y signal in terms of nT
    ;->Change data in V (original data format) to in nT by dividing by the system gain ->applies only to UNH ULF system.
	station_code(station_index/2)  = 'ISR'
	station_index = station_index + 2
endif




;====== Specify graphic format
;file_format = 'x'
if file_format eq 'x' then begin
    graphic_type = '.jpg'
	set_plot,'X'
endif else begin
    graphic_type = '.ps'
	set_plot,'PS'
endelse

;====== Specify directory and filename where plots will be saved
file_subdir_plot = file_subdir_plot
file_name_plot   = date + '_' + start_time + '_' + end_time +'_' + $
                   station_names + graphic_type
file_path_plot   = plot_dir + '/' + file_name_plot
file_path_base   = plot_dir + '/' + $
                   date + '_' + start_time + '_' + end_time +'_' + $
                   station_names


;====== Setup graphic device and plot
loadct, 39
!p.background=255
!p.color=0

if !d.name eq 'PS' then begin
   device, filename=file_path_plot, bits=8, /color, /inches, $
           xoffset=0.75, yoffset=0.5, xsize=7.0, ysize=9.5
;   print, 'Device:', !d.name
endif
if !d.name eq 'X' then begin
   device, true = 24, decomposed = 0, retain = 2
   window, 0, retain=2, xsize=640, ysize=828, title=title
;   print, 'Device:', !d.name
endif
;if !d.name eq 'WIN' then begin
;    window, 0, retain=2, xsize=1024 ,ysize=768, title=title
;    print, 'Device:', !d.name
;endif


;====== Set up the plotting window dimensions
leftedge  = 0.05 ;bugger
leftedge = 0.13
rightedge = 0.87
topedge   = 1.0 ;bugger
topedge   = 0.9
dataysize  = 0.16                    ;vertical size of the line plots
gapsize    = 0.04                   ;vertical size of the gap between some panels
xwinsize   = rightedge - leftedge    ;horizontal panel size
x0  = leftedge
x2  = leftedge
x4  = leftedge
x6  = leftedge
;x8  = leftedge
;x10 = leftedge
x1  = rightedge
x3  = rightedge
x5  = rightedge
x7  = rightedge
;x9  = rightedge
;x11 = rightedge
y0  = topedge - dataysize
y2  = y0 - dataysize - gapsize
y4  = y2 - dataysize - gapsize
y6  = y4 - dataysize - gapsize
;y8  = y6 - dataysize - gapsize
;y10 = y8 - dataysize - gapsize
y1  = y0 + dataysize
y3  = y1 - dataysize - gapsize
y5  = y3 - dataysize - gapsize
y7  = y5 - dataysize - gapsize
;y9  = y7 - dataysize - gapsize
;y11 = y9 - dataysize - gapsize


;====== Set up plot positions
position1 = [x0,y0,x1,y1]
position2 = [x2,y2,x3,y3]
position3 = [x4,y4,x5,y5]
position4 = [x6,y6,x7,y7]







doy   = 100 ; fixed (temp)
winsize = convert_coord(xwinsize, dataysize, /normal, /to_device) ;Convert coordinates for the window size from normal to device coords







;print,'Step size = ',(duration/ncols) * spm * mph,' sec
;print,'nrows = ', nrows, ' ,  ncols = ', ncols
;print,'f_max = ', maxfreq_calc,' Hz'


;====== Setup Y axis labels for FFT
if fix(maxfreq) gt 1 and fix(maxfreq) le 5 then begin
    freq_ytickcount = maxfreq
    freq_yticklabel = strarr(freq_ytickcount + 1)
    freq_yticksize = maxfreq / freq_ytickcount
    freq_yticklabel = strarr(freq_ytickcount + 1)
    for y = 0, freq_ytickcount do begin
        freq_yticklabel(y) = strtrim(string(format='(F7.1)', freq_yticksize * y), 1)
    endfor
endif

if maxfreq eq 1.000 then begin
    freq_ytickcount = 5.0
    freq_yticklabel = strarr(freq_ytickcount + 1)
    freq_yticksize = maxfreq / freq_ytickcount
    freq_yticklabel = strarr(freq_ytickcount + 1)
    for y = 0, freq_ytickcount do begin
        freq_yticklabel(y) = strtrim(string(format='(F7.1)', freq_yticksize * y), 1)
    endfor
endif

if maxfreq gt 0.1 and maxfreq lt 1.0 then begin
    freq_ytickcount = maxfreq*10
    freq_yticklabel = strarr(freq_ytickcount + 1)
    freq_yticksize = maxfreq / freq_ytickcount
    freq_yticklabel = strarr(freq_ytickcount + 1)
    for y = 0, freq_ytickcount do begin
        freq_yticklabel(y) = strtrim(string(format='(F7.1)', freq_yticksize * y), 1)
    endfor
endif

if maxfreq eq 0.1 then begin
    freq_ytickcount = 5.0
    freq_yticklabel = strarr(freq_ytickcount + 1)
    freq_yticksize = maxfreq / freq_ytickcount
    freq_yticklabel = strarr(freq_ytickcount + 1)
    for y = 0, freq_ytickcount do begin
        freq_yticklabel(y) = strtrim(string(format='(F7.2)', freq_yticksize * y), 1)
    endfor
endif


;====== Set up plot options
charsize1 = 0.8
charsize2 = 1


;====== Plot graphs (time-series and spectrogram; one stations (4 panels) per page)
page_index = station_index/2   ;determine number of page to be plotted in PS format. Prints data from up to 3 stations in one page.
spec_array = dblarr(2, datacount)

for plot_index = 0, station_index-1, 2 do begin

;====== Plot time-series (Bx)
plot, plot_array_Bx(plot_index, *), plot_array_Bx(plot_index+1,*), nsum = nsum_value, pos=position1, $
    xstyle=1, xticklen=-0.05, xcharsize=charsize1, $
    xticks=xtick_count, xminor=xminor_count, xtickv = tick_values, xtickname=xtick_labels, $
    ystyle=1, yticklen=-0.01, ycharsize=charsize1, $
    yrange=[-max_B_field, max_B_field], $
    ytitle = strtrim(station_code(plot_index/2),2) + ' Bx dB/dt (nT/sec)'


;====== Plot FFT spectrogram (Bx)
plot, [0,max(times)], [0,1], /noerase, /nodata, pos=position2,$
    xstyle=1, xticklen=-0.05, xcharsize=charsize1, $
    xticks=xtick_count, xminor=xminor_count, xtickv = tick_values, xtickname=xtick_labels, $
    yticks=freq_ytickcount, yminor= yminor_count,  ytickname=freq_yticklabel, $
    ystyle=1, yticklen=-0.01, ycharsize=charsize1,$
    ytitle= strtrim(station_code(plot_index/2),2) + ' Bx Freq (Hz)'
spec_array(0, *) = plot_array_Bx(plot_index, *)
spec_array(1, *) = plot_array_Bx(plot_index+1, *)

calcspec, spec_array, spectra, duration, period, sph, nfft, pstart, missing
greyplot, spectra(*,*), position2, winsize, doy, times, pstart, duration, missing, upper, lower

;====== Plot time-series (By)
plot, plot_array_By(plot_index, *), plot_array_By(plot_index+1,*), nsum = nsum_value, pos=position3, /noerase, $
    xstyle=1, xticklen=-0.05, xcharsize=charsize1, $
    xticks=xtick_count, xminor=xminor_count, xtickv = tick_values, xtickname=xtick_labels, $
    ystyle=1, yticklen=-0.01, ycharsize=charsize1, $
    yrange=[-max_B_field, max_B_field], $
    ytitle = strtrim(station_code(plot_index/2),2) + ' By dB/dt (nT/sec)'


;====== Plot FFT spectrogram (By)
plot, [0,max(times)], [0,1], /noerase, /nodata, pos=position4,$
    xstyle=1, xticklen=-0.05, xcharsize=charsize1, $
    xticks=xtick_count, xminor=xminor_count, xtickv = tick_values, xtickname=xtick_labels, $
    yticks=freq_ytickcount, yminor= yminor_count,  ytickname=freq_yticklabel, $
    ystyle=1, yticklen=-0.01, ycharsize=charsize1,$
    ytitle= strtrim(station_code(plot_index/2),2) + ' By Freq (Hz)'
spec_array(0, *) = plot_array_By(plot_index, *)
spec_array(1, *) = plot_array_By(plot_index+1, *)
calcspec, spec_array, spectra, duration, period, sph, nfft, pstart, missing
greyplot, spectra(*,*), position4, winsize, doy, times, pstart, duration, missing, upper, lower

;======Print main titles
main_title1 = yyyy +'/'+mm+'/'+dd+'  '+start_hour+':'+start_min+'-'+end_hour+':'+end_min+' UT'
xyouts, 0.45, .92, main_title1, /normal, alignment=0.5, charsize=charsize2
main_title2 = 'Page ' + strtrim(string(plot_index/2+1),2) + '/' + strtrim(string(page_index),2)
xyouts, 0.82, .92, main_title2, /normal, alignment=0.5, charsize=charsize2

x_title = 'Universal Time (hh:mm)'
xyouts, 0.45, y6-0.05, x_title, /normal, alignment=0.5, charsize=charsize2

endfor


;==========================================================================
; Reset graphic device
print, file_path_base

if !d.name eq 'PS' then begin
    device, /close
    cmd_str = '/usr/bin/convert ' + file_path_base + '.ps '+ file_path_base + '.jpg'
    spawn, cmd_str
endif
;if !d.name eq 'WIN' then begin
;	WRITE_JPEG, '/tmp/test1.jpg'; [, /ORDER] [, /PROGRESSIVE] [, QUALITY=value{0 to 100}] [, TRUE={1 | 2 | 3}], tvrd()
;    window, /close
;endif

end