Data Model about framework HOT 1 CLOSED

Data Model

An internal representation of the data to be processed can be realized in a base class that contains the most commonly used functions and properties of astronomical data, such images and spectra. This base class implements a data model that loosely corresponds to a FITS file and reflects the structure of the FITS. Let’s call this base class DataModel.
Different instruments sometimes use different header keywords to the same properties. DataModel provides a standard interface to access these properties, allowing libraries functions to be instrument independent. To achieve this, FITS readers will return objects of a sub-class of DataModel. This sub-class will handle all the instrument specific case when needed, and simply defaults to common cases otherwise.

Properties of Data Model Objects

It needs to be decided whether data objects are mutable, inmutable or mixed, where the data is inmutable but the properties are mutable.

DataModel class must provide methods to create new data objects, clone or (shallow) copy data objects.

DataModel does not implement arithmetic operations such as adding, subtracting two data objects, or other operations used in data processing, such as cut-out or mosaicing. Instead, other libraries will provide this capability.

DataModel shall not perform I/O operations from and to disks. Instead standard or instrument specific readers and writers shall be used.

from framework.