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imagefromascii - Constructor

	Package	general
	Module	images
	Tool	image

Construct an AIPS++ image by conversion from an ascii file

Synopsis
imagefromascii(outfile, infile, shape, sep, csys, linear, overwrite)

Arguments

outfile	in	Output image file name
		Allowed:	String
		Default:	unset
infile	in	Input ascii disk file name
		Allowed:	String
shape	in	Shape of image
		Allowed:	Vector of integers
sep	in	Separator in ascii file
		Allowed:	String
		Default:	' '
csys	in	Coordinate System
		Allowed:	Coordsys tool
		Default:	unset
linear	in	Make a linear Coordinate System if csys not given
		Allowed:	T or F
		Default:	F
overwrite	in	Overwrite (unprompted) pre-existing output file ?
		Allowed:	T or F
		Default:	F

Returns
Image tool or fail

Description

This constructor is used to convert an ascii disk file to an AIPS++ image file. 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 destroy the Image tool (with the done function) this temporary image is deleted.

You must specify the shape of the image. The image must be stored in the ascii file, one row at a time. This row must be of the correct length and there must be the correct number of rows. For example, let us say the shape of your image is [nx,ny,nz] = [3,4,2], then the image should be stored as

1 1 1                   # row 1; y = 1, z = 1
2 2 2                   # row 2; y = 2, z = 1
3 3 3                   # row 3; y = 3, z = 1
4 4 4                   # row 4; y = 4, z = 1
1.5 1.5 1.5             # row 5; y = 1, z = 2
2.5 2.5 2.5             # row 6; y = 2, z = 2
3.5 3.5 3.5             # row 7; y = 3, z = 2
4.5 4.5 4.5             # row 8; y = 4, z = 2

The Coordinate System, provided as a Coordsys tool, 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 (unset), 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 of the pixels array (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.

Example

- im := imagefromascii('myimage.app', 'myimage.ascii', shape=[128,128])