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

15.2. OBSERVATION DATA STRUCTURES 169
12. WAVELENGTH START, WAVELENGTH END, WAVE INCREMENT: Applies
to a CVF AOT only. WAVELENGTH START and WAVELENGTH END are the
wavelengths at the beginning and end of a CVF scan. WAVE INCREMENT is the number
of wheel steps between each position in the scan. Type: float (WAVELENGTH START,
WAVELENGTH END) and byte (WAVE INCREMENT). Unit: microns.
13. RA: RA(J2000) of the centre of the final MOSAIC that is constructed from the EXPO-
SUREs in the SCD. Type: double. Unit: decimal degrees.
14. DEC: DEC(J2000) of the centre of the final MOSAIC that is constructed from the EX-
POSUREs in the SCD. Type: double. Unit: decimal degrees.
15. ROLL: As for SCD (see Section 15.2.2).
15.2.4 Science Analysed Data (SAD)
The SAD may contain an EXPOSURE or a MOSAIC. In CIA programming terminology the set
of EXPOSUREs used to create the MOSAIC is referred to as the origin and the actual MOSAIC
itself as the future. This gives rise to two flavours of SAD: origin SAD and future SAD.
Two array substructures exist in the SAD data structure: CCIM and CMAP. (Don’t confuse
these substructures with the data products of the same name, they have been named ‘CCIM’
and ‘CMAP’ for historical reasons.) We use these substructures for:
1. CCIM
Holds an averaged EXPOSURE in detector coordinates. It may be used to hold your CIA
processed data or AAR from the CCIM data product file.
2. CMAP
In the origin SAD it holds an EXPOSURE calibrated in astronomical coordinates. In
the future SAD it holds a MOSAIC. It may be used to hold your CIA processed data or
AAR from the CMAP data product file or the CMOS data product file. Because the size
of the MOSAIC may vary, IDL pointers are used to handle the CMAP data structure.
The routines of Chapter 16 make this transparent to the user, so you need only think of
this structure in terms of fields that you may manipulate. The CMAP substructure is of
dimensions: 32 × 32 for holding an EXPOSURE; dynamic when used to hold a MOSAIC.
The SAD contains all the standard fields of Section 15.2.1 and in addition extra fields associated
with the type of analysis which may have been performed on the data. For example, the
PFOV is a standard field because it is relevant to an image regardless of the processing, but the
unit of pixel intensity, TUNIT, is dependent on how the data has been processed. Below is a
list of fields that are considered most useful to the CIA user.
1. CCIM/CMAP: Both CCIM and CMAP each contain further subfields. To access these
replace DATA with either CCIM or CMAP.