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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 routines beyond those which are applicable to all Frames.
Copyright (C) 2014 Science & Technology Facilities Council
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A Library for Handling
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Coordinate Systems
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