ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

80 CHAPTER 12. DATA SLICING
CIA> nscd = sscd_get( ’nscd’, erd_sscd )
CIA> print, nscd
41
Using a simple IDL loop we can convert all the ERD SCDs to SPD SCDs in one line:
CIA> spd_scds = strarr( nscd )
CIA> for i = 0, nscd - 1 do spd_scds[i] = erd2spd( erd_scds[i], $
CIA> ssid=erd_sscd, /del)
Note that the del keyword is set to delete the ERD SCDs from memory as the SPD
SCDs are created.
Finally, for convenience create a new variable containing the name of the SPD SSCD.
Since the name of SSCD is unchanged this is achieved by copying the variable erd sscd:
CIA> spd_sscd = erd_sscd
NowwecanremovetheoldERD SSCD and its ERD SCDs from disk.
sscd remove to do just that.
We can use
CIA> sscd_remove, erd_sscd, dir=scd_dir
Finally we can save the SPD SSCD with its new SPD SCDs.
CIA> sscd_write, spd_sscd, dir=scd_dir
5. As an alternative to the above steps using spdtoscd we can directly create SPD SCDs in
memory (and on disk) with the SPD data product:
CIA> spdtoscd, ’cisp14300601.fits’, spd_sscd, dir=product_dir, $
CIA> scd_dat=scd_dir, ack=ack
6. Our next step is to find the data we require from the SSCD. The whole AOT is contained
within the SSCD, but we may be only interested in a single CONFIGURATION. In our
example here, we have a raster observation with two CONFIGURATIONs, one for filterwheel
LW6 and one for LW3, and in addition several STATEs corresponding to internal
calibrations and detector stabilisation.
We can get an overview of the contents of the SSCD with sscd info – it lists important
parameters of all the SCDs in an SSCD. (These parameters are simply values extracted
from fields within the SCD structure.) The contents of the SCDs are in fact a history of
the observation. Reading down through the list below you can see the behaviour of CAM
through out the AOT. In particular, look out for which filter (the field FLTRWHL) and
which OP-MODE (the field MODE) is given for each SCD. Remember, in this observation
the filter defines the difference between the two CONFIGURATIONs.