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

Chapter 15
CIA data structure high-level
architecture
This chapter describes the high-level architecture of CIA data structures. It is hoped that it will
help you to understand how your data is organised within CIA. Examples are included to aid
description of the data structures. These examples include CIA manipulation routines which
may be unfamiliar to you – in such cases refer to Chapter 16 for a description.
15.1 Introduction
The data is managed in a CIA session by purpose designed data structures. These structures
may seem large and unwieldy to the novice user, but experience has shown that they are the
most convenient way of managing CAM data. AOTs can be quite complex and many CAM
FRAMEs may be accrued during a typical observation. In addition the many CAM parameters
that exist need to be stored along with the FRAMEs, IMAGEs, EXPOSUREs and MOSAICs.
The structures attempt to neatly store all these data. CIA makes the structures as transparent
as possible to the user by using dedicated manipulation routines (see Section 16), or by allowing
you to transform CIA data structures into ordinary IDL structures (PDS). It is hoped that
this chapter will help you work with the structures, but not get too deeply involved with their
architecture.
The structures are broadly grouped into those containing observation data (see Section 15.2)
and those that contain calibration data (see Section 15.3).
15.2 Observation data structures
Observation data structures are designed to hold actual image data from a CAM observation and
detailed information about CAM and ISO parameters during the observation. Where possible
the data is presented in fields of the structure in a user-friendly format, i.e. the original telemetry
coded parameters have been converted to more readable strings.
The structures containing observation data are outlined below and a reference to a more
detailed section is given with each description.
Science CAM Data (SCD) – ERD/SPD Level The SCD structure has two flavours, one
is used to hold data of ERD product type, the ERD SCD, and the other of SPD product
type, the SPD SCD. The ERD SCD contains all the EOI and RESET FRAMEs from a
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