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

66 CHAPTER 9. THE DATA PRODUCTS AND CIA DATA STRUCTURES
Science Analysed Data (SAD) – AAR Level Contains two EXPOSUREs, one calibrated
in detector coordinates (from the CCIM data product) and the other calibrated in celestial
coordinates (from the CMAP data product). The SAD is also used to hold EXPOSUREs
(from the CMOS data product). In addition to AAR data products, the SAD may be used
to hold CIA calibrated EXPOSUREs and MOSAICs.
Set of Science Analysed Data (SSAD) Contains a catalogue of a set of SADs. Its function
is analogous to that of the SSCD. In general, best use of the SSAD is made when it
catalogues SADs that belong to a single CONFIGURATION. However, it may catalogue
any subset of SADs from an AOT.
Diagnostic Specific Data (DSD) Contains physical parameters of the camera: temperatures,
voltages, wheel positions, etc. It is directly used only by instrument experts for
in-depth investigation of ISOCAM behaviour. Such data that is of interest to the normal
user is also held in the SCD. Documentation of the DSD structure is beyond the scope of
the CIA User’s Manual 7 .
9.4.3 Calibration Data Structure (CDS)
One generic structure is used to contain all of the different types of calibration data. This is
the Calibration Data Structure. It contains a dynamic substructure or field named DATA and
a standard set of fields. DATA holds the actual calibration data: dark images, flat images,
point spread images, etc. The standard fields hold information related to the nature of the CDS
structure itself, e.g. the CDS name and size.
The CDS is almost a direct conversion from FITS format data to IDL data structure, the
important difference being that the actual image data are scaled, so the BZERO and BSCALE
keywords are discarded. So the CDS differs from the SCDs/SADs in that the CAM parameters
are NOT presented in the CIA user friendly format, but as raw values taken from the CAL-G
FITS files.
9.4.4 Regular IDL structures
Unlike the structures described in Sections 9.4.2 and 9.4.3 the structures described here are
regular IDL structures.
Prepared Data Structure (PDS) Currently, three flavours of the PDS exist: a CVF PDS, a
raster PDS (also known as a raster data structure) and a general PDS. This data structure
is formed from an SSCD (and its SPD SCDs) and is used to hold all the sliced (i.e.
prepared) data that you need to perform calibration. Usually, the data in a PDS correspond
to a single CONFIGURATION.
See Section 15.5 for more on details of PDSs.
7 Further details on the DSD may be found in the ISO Data Product Document or the CAM Parameter
Characteristic Document, 1991, ref ISOCAM ST110.