MDI_OBSTIME(3)



NAME

     MDI_obstime,   obstime_correction,   DPC_obstime_correction,
     get_data_products,  data_product_exists  - functions associ-
     ated with the MDI observables.


SYNTAX

     #include <MDI.h>
     #include <data_qual.h>

     TIME MDI_obstime (SDS *img)
     double obstime_correction (unsigned int dpc)
     double DPC obstime_correction (struct DPC dpc)
     unsigned int *get_data_products (TIME t, int level)
     int data_product_exists (unsigned int dpc, TIME t, int level)
     int data_product_exists_near (unsigned int dpc, TIME t,
         double delta, int level)


DESCRIPTION

     obstime_correction  and  DPC_obstime_correction  return  the
     difference between observing time (center of the integrating
     interval) and reference time provided by the MDI image  pro-
     cessor for the referenced data product code.  The correction
     is in seconds,  in  the  sense  obs_time  -  ref_time.   The
     assumed offsets are:
     -13 min for the low-rate time-weighted averages;
     -1.5 min for summed magnetograms;
     +0.5 min for 30-second high-rate observables;
     0.0 for all other observables

     MDI_obstime simply returns the observation time of an  image
     based  on  whatever  information  is  available in the image
     header - T_OBS; or T_REF plus any other keywords required to
     calculate  the  time  correction.   If there is insufficient
     information it returns T_MISSING.

     get_data_products() returns a mallocd list of all  the  data
     product  codes (as unsigned ints) for which records exist at
     the referenced processing level at the given time.  It reads
     from  the appropriate obslog, files organized with a resolu-
     tion of one-minute.  Data products  whose  integration  time
     extends  over  more  than  one  minute  are included for all
     minutes of the observation.

     data_product_exists() returns a 1 or 0 according to  whether
     the  requested data product exists at the requested level of
     processing  within  one  minute  of  the   requested   time.
     data_product_exists_near() does likewise, with the tolerance
     interval extended +/- delta seconds of the requested time.


FILES

     /home/soi/logs/obslog[0|1]


SEE ALSO

     MDI_DPC_decode(3); SOI-TN-97.138


DIAGNOSTICS

     get_data_products()  returns  all  0's  and  sets  soi_errno
     appropriately if the corresponding obslog cannot be read, or
     if the requested time is outside the range of times  in  the
     obslog.


BUGS


AUTHOR

     Rick Bogart


HISTORY

     2000-05-15     SOI Version 4.7