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Description:
A CmpFrame is a compound
Frame which
allows two component Frames (of any class) to be merged together to form a more
complex Frame. The axes of the two component Frames then appear together in the
resulting CmpFrame (those of the first Frame, followed by those of the second
Frame).
Since a CmpFrame is itself a Frame, it can be used as a component in forming further
CmpFrames. Frames of arbitrary complexity may be built from simple individual Frames in
this way.
Also since a Frame is a Mapping, a CmpFrame can also be used as a Mapping. Normally, a
CmpFrame is simply equivalent to a UnitMap, but if either of the component Frames
within a CmpFrame is a Region (a sub-class of Frame), then the CmpFrame will use the
Region as a Mapping when transforming values for axes described by the Region. Thus
input axis values corresponding to positions which are outside the Region will result
in bad output axis values.
Constructor Function
Inheritance
The
CmpFrame class inherits from the Frame class.
Attributes
The CmpFrame class does
not define any new attributes beyond those which are applicable to all Frames.
However, the attributes of the component Frames can be accessed as if they were
attributes of the CmpFrame. For instance, if a CmpFrame contains a
SpecFrame and a
SkyFrame, then the CmpFrame will recognise the
"
Equinox"
attribute and forward
access requests to the component SkyFrame. Likewise, it will recognise the
"
RestFreq"
attribute and forward access requests to the component SpecFrame.
An axis index can optionally be appended to the end of any attribute name,
in which case the request to access the attribute will be forwarded to the
primary Frame defining the specified axis.
Functions
The CmpFrame class does
not define any new functions beyond those which are applicable to all Frames.
Copyright (C) 2014 Science & Technology Facilities Council
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A Library for
Handling
World Coordinate Systems
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