1.1.1.0 image.newimagefromshape

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image.newimagefromshape - Function

1.1.1 Construct an empty CASA image from a shape
Description

This function creates a CASA image file with the specified shape. All the pixel values in the image are set to 0.

If outfile is given, the image is written to the specified disk file. If outfile is unset, the on-the-fly Image tool returned by this function is associated with a temporary image. This temporary image may be in memory or on disk, depending on its size. When you destroy the on-the-fly Image tool (with the done function) this temporary image is deleted.

The Coordinate System, provided as a record describing a Coordsys tool (created via coordsys.torecord(), for instance), is optional. If you provide it, it must be dimensionally consistent with the pixels array you give (see also coordsys).

If you don’t provide the Coordinate System, a default Coordinate System is made for you. If linear=F (the default) then it is a standard RA/DEC/Stokes/Spectral Coordinate System depending exactly upon the shape (Stokes axis must be no longer than 4 pixels and you may find the spectral axis coming out before the Stokes axis if say, shape=[64,64,32,4]). Extra dimensions are given linear coordinates. If linear=T then you get a linear Coordinate System.

Arguments


Inputs
outfile	Name of output image file. Default is unset.
	allowed:	string
	Default:
shape	Shape of image. Required.
	allowed:	intArray
	Default:	0
csys	Record describing Coordinate System. Default is unset.
	allowed:	any
	Default:	record
linear	Make a linear Coordinate System if csys not given?
	allowed:	bool
	Default:	false
overwrite	Overwrite (unprompted) pre-existing output file?
	allowed:	bool
	Default:	false
log	Write image creation messages to logger
	allowed:	bool
	Default:	true

Returns
casaimage

Example

"""
#
print "\t----\t newimagefromshape Ex 1 \t----"
im1=ia.newimagefromshape(’test2.data’, [64,64,128], overwrite=true)
cs1 = im1.coordsys(axes=[0,2])
im1.done()
im2 = ia.newimagefromshape(shape=[10, 20], csys=cs1.torecord())
cs1.done()
im2.done()
#
"""

The first example creates a zero-filled image file named test.data of shape [64,64,128]. If you examine the header with ia.summary() you will see the RA/DEC/Spectral coordinate information. In the second example, a Coordinate System describing the first and third axes of the image test2.data is created and used to create a 2D temporary image.

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