1.1.1.0 image.fromshape

NRAO Home > CASA > CASA Toolkit Reference Manual

image.fromshape - 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. One may create either an image with float valued pixels (type=’f’) or a complex valued image (type=’c’).

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

The Coordinate System, provided as a Coordsys tool, is optional. If you provide it, it must be dimensionally consistent with the shape that you specify (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.

The method returns True if successful, False otherwise.

Arguments


Inputs
outfile	Name of output image file. Default is unset.
	allowed:	string
	Default:
shape	Shape of image. Must be specified.
	allowed:	intArray
	Default:	0
csys	Coordinate System. Default is unset.
	allowed:	record
	Default:
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
type	Type of image. ’f’ means Float, ’c’ means complex.
	allowed:	string
	Default:	f

Returns
bool

Example

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

The first example creates a zero-filled \imagefile\ named {\sff
test.data} of shape [64,64,128]. If you examine the header with {\stff
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 {\sff test.data} is created and used to create a 2D temporary image.

__________________________________________________________________

[next] [prev] [prev-tail] [front] [up]

More information about CASA may be found at the CASA web page

This code is available under the terms of the GNU General Public Lincense