IDL save sets

An IDL save set is the unique IDL feature which allows you to simply save variables into a file, without having to open the file, write to it and close it. IDL takes care of all that file I/O you normally associate with writing files. You simply do something like

save, file='some_name', var1, var2, var2,

The beauty of this is that you don't have to know what is in the file to access it. IDL stores all the info about the variables you saved, plus the data they contain. So to read the data, all you need to do is:

restore, 'some_name', /verbose

The verbose keyword lists the variables that were restored. Using the IDL help command then allows you to interrogate what the variables were!

For example, to access one of the RAL intermdiate files all you need to do is:

IDL> restore,'PO_CEP_RAL_SURVEY_IPS_1996134.DAT',/verbose
% RESTORE: Portable (XDR) SAVE/RESTORE file.
% RESTORE: Save file written by friedel@hydra.mpae.gwdg.de, Sun Jan 12
           15:46:44 1997.
% RESTORE: Restored variable: INPUT_HEADER.
% RESTORE: Restored variable: INPUT_DATA.

IDL> help, INPUT_HEADER, /stru
** Structure HEADER_IPS_SURVEY, 23 tags, length=3104:
   DATATYPE        STRING    'POLAR/CEPPAD/IPS normal mode SURVEY'
   NPOINTS         LONG               907
   NDETECTORS      LONG                10
   NBANDS          LONG                17
   NSECTORS        LONG                16
   NLUTS           LONG                 2
   DETECTORS       LONG      Array(10)
   TSTART          DOUBLE       1.2106369e+09
   TSTOP           DOUBLE       1.2107232e+09
   CH_POSITIONS    FLOAT     Array(2, 17, 10, 2)
   COUNT_CAL       FLOAT     Array(2)
   ENERGY_CAL      FLOAT           1.00000
   PEDESTALS       FLOAT     Array(10, 2, 2)
   CAL             INT              0
   RAT             INT              0
   DIV             INT              0
   CLEAN           INT              0
   SUBTRACT        INT              0
   TITLE           STRING    'POLAR/CEPPAD/IPS normal mode SURVEY'
   XTITLE          STRING    'UT:'
   YTITLE          STRING    'Energy'
   ZTITLE          STRING    'Cts'
   PTITLE          STRING    Array(10)

IDL> help, INPUT_DATA, /stru
** Structure DATA_IPS_SURVEY, 4 tags, length=10896:
   TIME            DOUBLE       1.2106369e+09
   DATA            FLOAT     Array(16, 10, 17)
   LUT             BYTE         0
   FLAG            BYTE         1

For a full description of the INPUT_HEADER and INPUT_DATA structure look at the RAL documentation from their ftp site. But even as is it's not difficult to read - the data is an array of 907 elements of the data structure, and at each time you have an data array of 16 sectors by 10 detectors by 17 energy channels, in counts. The time is in TAI (International Atomic Time). Both PAPCO and the RAL software include a full library of IDL routines for this format, which comes from the CDS time conversion software written for SOHO. You can download this library here.

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Reiner Friedel Produced and Maintains this CCR Web Page.
Last updated Wednesday March 26, 1997