GOES data processing software 

Disclaimer This software is provided AS IS.  
Neither the author or NASA is responsible for any 
damage incurred directly or indirectly 
through the use of this software.

Om Sharma, RDC, version @ AUG 13 1995

The gvar program allows one to convert GVAR data
(recorded from a goes satellite) into radiometrically
calibrated images.

To obtain LIVE goes images: 

1) Identify the file containing raw data 
  Data broadcast from the goes8 satellite is captured by
  the antenna on building-22@gsfc. A roving archive of the 
  last 8-12 hours of data is mantained on local disks attached
  to the machine goessun.gsfc.nasa.gov. 
  If you have automount running on your system you can list all 
  the available data using the following command: 

>ls -tlr /net/goessun-f.gsfc.nasa.gov/Goes8/*/*

2) Use the gvar parsing program to parse the raw data to 
 a suitable format for your use.

Each of the options are explained here in greater detail


VERBOSE     -h more verbose description of the following options

-----------------------------------------------------------------
INSTRUMENT  -i <instrument>  	       default: none
                [none imager sounder iIcse 
		 sIcse iSpacelookStats iNav sNav]
Focus attention to specified instrument.  
Once the user has specified an instrument, all further arguments
will apply to that instrument, unless the user specifically 
changes the instrument. 
eg: gvar -i imager -c all -f tiff -i sounder -c all -f bin
all the imager channels are to be written in the
tiff format and all the sounder files written in binary format.
selecting the same instrument again will produce a new set of output
files. 

NONE:
  No instrument specified.
IMAGER:
  Specify imager. Imager has 5 channels (VIS->Ch1).
SOUNDER:
  Specify sounder. Sounder has 19 channels (VIS->Ch19).
IICSE:
  Make ASCII file contatining imager instrument compensation and
  servo error terms.
SICSE:
  Make ACSII file containing sounder instrument compensation and 
  servo error terms.
ISPACELOOKSTATS
  Make ASCII files containing imager space look statistics 
  for all channel
INAV:
  Print Navigation paramters from block 0 (for imager)
SNAV:
  Print Navigation parameters from block 11 (for sounder)              
-----------------------------------------------------------------
 FILETYPE    -f <file>                 default: none
                [none bin jpeg tiff tifftile tiffstrip]
Specify an output filetype for selected instrument.

NONE:  Do not write any file.
BIN :  Binary files (The width, height and datatype will be 
       appended to the filename.)
JPEG:     JPEG encoded files (CAUTION: jpeg does only uchar )  
TIFF:     Tiff 6.0 file. Regular tiff.
TIFFTILE: Tiff 6.0 tile file. Each tile is  (128x128).
TIFFSTRIP:Tiff 6.0 strips file. Each strip is (Xsize x 128 ).
-----------------------------------------------------------------
 TIMESTAMP  -T <stamp>                 default: fromFilename
                [fromFilename framestart region]
Controls the naming of <imager/sounder> files.
The names have the following syntax: 
  <timestamp>.<satel><instr><ch>.<units>.<file>
eg: 9412161212.G8I1.albdo.ttif

FROMFILENAME: 
	<timestamp> set to the name of the file being processed.
FRAMESTART :
	<timestamp> set to the gmt time at the start of the frame.
REGION: 
	<timestamp> set to the gmt time at the start of the region
-----------------------------------------------------------------
 START      -s <VISpixel,VISline>      default: from gvar
Specify that the (imager/sounder) sector start at (VISpixel,VISline). 
If this argument is not supplied, or if -1 is suppled as the 
argument, information about start of frame is obtained from GVAR.
-----------------------------------------------------------------
 END        -e <VISpixel,VISline>      default: from gvar
Specify that the (imager/sounder) sector end at (VISpixel,VISline). 
If this argument is not supplied, or if -1 is suppled as the 
argument, information about end of frame is obtained from GVAR.
-----------------------------------------------------------------
 REGION     -r <CentralVISPixel,CentralVISLine,Pixels,Lines>  
				       default: from gvar
Specify that the (imager/sounder) sector is centered  at 
(CentralVISpixel,CentralVISline) and of size (Pixels, Lines).
This is equivalent to specifying
-s CentralVISpixel-Pixels/2,CentralVISline-Lines/2
-e CentralVISpixel+Pixels/2,CentralVISline+Lines/2

-----------------------------------------------------------------
 REGION     -R <CentralVISLongitude,CentralVISLatitude,Pixels,Lines>  
				       default: from gvar
A best guess of the conversion from 
	CentralVISLongitude -> CentralVISPixel
    and CentralVISLatitude  -> CentralVISLine is applied. 
Specify that the (imager/sounder) sector is centered  at 
(CentralVISpixel,CentralVISline) and of size (Pixels, Lines).
This is equivalent to specifying
-s CentralVISpixel-Pixels/2,CentralVISline-Lines/2
-e CentralVISpixel+Pixels/2,CentralVISline+Lines/2
-----------------------------------------------------------------
 AREA       -A <[+/-] Mbytes>          default: inactive 
Maximum area of visible image in MegaBytes. 
Process sector only if the maximum allowable area of the 
visible image is greater than / less than 
specified Mega Bytes. 
-----------------------------------------------------------------
 LINKNAME    -l toggle link to latest  default: none
Create a link to the lastest file processed and call it
<dirname>/latest.<fileType>. 
-----------------------------------------------------------------
 CHANNEL     -c <channel>              default: all
                [all 1 2 .. ]
Focus attention to specified channel
Once the user has specified a channel all further arguments will 
apply to that channel, unless the user specifically changes the 
channel. 
eg: gvar -i imager -c 1 -f tiff -c 2 -f bin
imager channel 1 is to be written tiff format and channel 2 in
the binary format.
-----------------------------------------------------------------
  HOURS      -H <start,end>            default: 0,23
                GMT hours
Start,end time in GMT hours.
Images that do not start between these hours will not be processed.
-----------------------------------------------------------------
  WORDTYPE   -w <wordtype>             default: none
                [none char uchar short ushort int uint float double]
Specify a filetype for selected instrument and channel.
Data
Type  Bytes   MIN                                MAX
CHAR    1  ( -128                  to            127 )
UCHAR   1  (   0                   to            255 )
SHORT   2  ( -32768                to           32767)
USHORT  2  (   0                   to          65535 )
INT     4  ( -214748367            to      2147483647)
UINT    4  ( 0                     to       429496729)
FLOAT   4  ( 1.17549435E-38F       to  3.40282347E+38)
DOUBLE  8  ( 2.2250738585072014E-308 1.7976931348623157E+308 )
-----------------------------------------------------------------
  UNITS      -u <units>                default: counts
                [counts radiance     
                 tstar tscene modeA    (for IR ) 
                 albedo albedo2]       (for VIS)
Specify the output units for selected instrument and channel.
All conversion calculations are done in double precision and
are truncated to user specified units.
COUNTS:   
  GVAR natural units. No conversions performed.
RADIANCE: (units erg/cm2/sec/steradian/cm-1)
  Apply GVAR specified coefficients to convert from counts 
  to radiance. 
TSTAR: Brightness Temperature (units K )
  Apply inverse planck function to compute the brighness temperature.
  First counts are converted to radiance. Then, NOAA specified 
  wavenumbers for (imager/sounder) channels are utilized in the 
  inverse planck function to obtain brighness temperature.
  CAUTION: This will produce 'strange' results for the visible
  channels
TSCENE: Scene Temperature( units K )
  Apply NOAA stipuated corrections to brighness temperature.
  CAUTION: This will produce 'strange' results for the visible
  channels
MODEA: ( units char 0-255)
  NOAA scheme to convert scene temperatures to single byte values.
    double val = SCENE_TEMPERATURE(kounts);
    if ( val < 242) amode = 418 - MAX(val,163);
    else amode = 660 - 2* MIN(val,330) ;
  CAUTION: This will produce meaningless results for the visible
  channels
ALBEDO: ( units %albedo )
  Apply GVAR specified coefficients to convert from counts to albedo.
  CAUTION: This will produce meaningless results for the IR
  channels  
ALBEDO2: (units %albedo)
  Apply GVAR specified coefficients to convert from counts to albedo.
  Use Spacelook statistics to determine the instrument bias. 
  CAUTION: This will produce meaningless results for the IR
  channels.
-----------------------------------------------------------------
  GAIN       -g <gain> {y=((x-b)/g)^G} default: 1.0
Specify the output gain for selected instrument and channel.
All conversion calculations are done in double precision and
are truncated to user specified units.
The following equation is used to specify the gain and bias
  y = [(x-bias)/gain]^Gamma
-----------------------------------------------------------------
  BIAS       -b <bias>                 default: 0.0
Specify the output bias for selected instrument and channel.
All conversion calculations are done in double precision and
are truncated to user specified units.
The following equation is used to specify the gain and bias
  y = [(x-bias )/gain]^Gamma
-----------------------------------------------------------------
  GAMMA      -G <gamma>                default: 1.0
Specify the output gamma for selected instrument and channel.
All conversion calculations are done in double precision and
are truncated to user specified units.
The following equation is used to specify the gain and bias
  y = [(x-bias )/gain]^Gamma
-----------------------------------------------------------------
  XSCALE     -x <pixels>               default: 1.0
Specify pixel scale factor for selected instrument and channel.
A nearest neigbour scheme for scaling is implemented.
The scale can be any real number. A number greater than one
produces supersampling and a number less than one subsampling.
Negative numbers are allowed as a convenience to the user.
Negative numbers are interpreted as 1/|x|
eg: -x-0.25 is identical to  -x4
-----------------------------------------------------------------
  YSCALE     -y <lines>                default: 1.0
Specify line scale factor for selected instrument and channel.
A nearest neigbour scheme for scaling is implemented.
The scale can be any real number. A number greater than one
produces supersampling and a number less than one subsampling.
Negative numbers are allowed as a convenience to the user.
Negative numbers are interpreted as 1/|y|
eg: -y-0.25 is identical to  -y4
-----------------------------------------------------------------
  DIRECTORY  -p <output_path>          default: ./   
Prepend the specified string to the filename. 
-----------------------------------------------------------------
  MAP        -M <map>                  default: none  
                  [none grid1 grid2 grid12 ] 
Burn the GVAR specified map pixels into the output data. 
NONE: Do not use map pixels
GRID1: Use grid set 1
GRID2: Use grid set 2
GRID12: Use grid set 1 and 2 
-----------------------------------------------------------------
  MAPVALUE   -m <counts>               default: 1023 
The value of the emborsed pixel in raw counts. 
-----------------------------------------------------------------
  COMPRESS   -C <scheme|QUALITY>       default: none|75
		for tiff:
                [cittrle ccittfax3 ccittrlew lzw
                 next packbits thunderscan pixarfilm]
		for jpeg: QUALITY [0 - 100] 
The specified compression scheme (if implemented) should
be applied. For TIFF specify one of cittrle ccittfax3 ccittrlew lzw
next packbits thunderscan pixarfilm. For JPEG an integer 
number indicating quality. 0->No compression, 100->Max compression.
-----------------------------------------------------------------
SNOOZE      -S <directory>             default: off 
After all the specified raw files are processed, wake up every 
minute and look for new files to process in the directory[s] 
specified. This option can be specified more than once to include
multiple directories. 
-----------------------------------------------------------------
DEBUG       -D <mode>                  default: none 
                [none header lineDoc block0time SAD CRC parity]
Print debug information in tabular form to file named DebugFile 
HEADER    :all valid block headers
LINEDOC   :block headers and imager line documentation.
BLOCK0TIME:various time strings associated with block0.
SAD       :valid block headers & sounder auxillary data header.
CRC       :CRC check each block and report.  
parity    :questionable parity check for each block
-----------------------------------------------------------------
COUNTER     -K toggle counter off      default: on
Turn the counter off. The counter marks % unread data.
-----------------------------------------------------------------
CMDFILE     -F <fileName>              default: none
Read the commands from fileName.
This option must be the first one specified to take effect.
-----------------------------------------------------------------
XECUTE      -X <scriptName>            default: none
The script pointed to by <scriptName> will be executed before 
the next new rawGvar file is processed.
-----------------------------------------------------------------
PRIORITY    -P                         default: off
Turn on priority frame processing.  When on, frames of different
priorities are processed as separate streams of data.  When off,
all frames are treated as the same priority, in one stream.
-----------------------------------------------------------------
File1
The filename of the recorded GVAR data. 
The last 10 hours of data is recorded on NFS mountable
disks on goessun-f.gsfc.nasa.gov. If you have automount
running on you system, you can list all available data 
files by typing the following command: 
> ls -lt /net/goessun-f.gsfc.nasa.gov/Goes8/*/*
-----------------------------------------------------------------
File2
The filename of more recorded GVAR data.
-----------------------------------------------------------------

If you have questions e-mail:sharma@climate.gsfc.nasa.gov


Usage examples for gvar: 
1. IMAGER, ROUND EARTH AT LOW RESOLUTION, 
  10*ALBEDO AND MODEA IN UNSIGNED CHAR , JPEG FORMAT
  COREGISTER DATA FOR ALL CHANNELS

gvar -i imager -c all -f jpeg \
-x-7 -y-4 \
-u modea -w uchar \
-c 3 -x-7 -y-2  \
-c 1 -u albedo -g 0.25 -x-28 -y-16 \
/net/goessun-f/Goes8/d10.raw/<fileName>


2. IMAGER FULL RESOLUTION, 10*ALBEDO AND 10*TSTAR 
  IN SHORT INTEGERS, TIFF FORMAT, SELECTING EASTERN 
  USA AND ATLANTIC (E.G. HURRICANE GORDON)

gvar -i imager -f tiff \
-s 16000,3500 -e 20000,6000 \
-c all -u tstar -w ushort -g 0.10 \
-c 1 -u albedo -g 0.10 \
/net/goessun-f/Goes8/d10.raw/<fileName>

3.SOUNDER FULL RESOLUTION, 10*TSTAR , COUNTS
  IN SHORT INTEGERS, TIFF FORMAT.

gvar -i sounder -f tiff -c all -w ushort \
-u tstar -g 0.10 \
-c 18 -u counts \
/net/goessun-f/Goes8/d10.raw/<fileName>