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

180 CHAPTER 15. CIA DATA STRUCTURE HIGH-LEVEL ARCHITECTURE
15.5 Prepared Data Structure (PDS)
The PDS was designed for convenience: to neatly hold all the data that you need for calibration
(see Chapter 13 and Chapter 20) in one structure. However, as described in Section 13.1.1 there
is a cost for such convenience. Because of individual differences between AOTs, four distinct
PDSs currently exist: a raster PDS, a CVF PDS, a BS PDS and a general PDS. As might be
expected the first three are specific to a raster, CVF and beam-switch observation respectively.
The latter is a multi-purpose PDS. The routines get sscdraster, get sscdcvf, get sscdbs and
get sscdstruct are used to create the appropriate PDS from an SSCD containing sliced SPD
SCDs.
In the following sections (Sections 15.5.1, 15.5.2, 15.5.3 and 15.5.4) each of the PDSs are
described. Tables listing the fields and substructures of the PDS are given and where appropriate
a reference to where you may find the original data in the SSCD and SCDs (Sections 15.2.1 to
15.2.5).
Note that the PDS differs from other observation data structures, i.e. SSCDs/SCDs and
SSADs/SADs, in that it is not accompanied by dedicated CIA manipulation routines. You may
treat the PDS like any other IDL structure.
15.5.1 Standard fields of the PDS
The fields that are present in all flavours of PDS are listed in the table below, along with a
brief description and where appropriate a reference to the SSCD or SCD field where the data
originates, or otherwise, the type of the data in the field.