Chandra X-Ray Observatory
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Last modified: December 2013

URL: http://cxc.harvard.edu/ciao/ahelp/get_axis_transform.html
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AHELP for CIAO 4.9

get_axis_transform

Context: crates

Synopsis

Return the axis transform from an IMAGECrate.

Syntax

get_axis_transform(crate, category)

Description

Argument Description
crate The image crate.
category One of: "WORLD", "PHYSICAL", or "LOGICAL" (case insensitive).

The get_axis_transform command extracts the 'default' axis transform of the given category from the input crate.

Example

>>> cr = read_file("image.fits")
>>> trans = get_axis_transform(cr, "WORLD")
>>> a = [[4096.5, 4096.5], [4823.2, 3843.87]]
>>> b = trans.apply(a)

We extract the WCS transfrom from the image - this translates SKY coordinates to equatorial - and use it to convert two positions: (4096.5,4096.5) and (4823.2,3843.87). The result for this dataset looks like:

>>> print(b)
[[ 116.06831306   37.90866459]
 [ 115.94249553   37.87407155]]

Bugs

See the bug pages on the CIAO website for an up-to-date listing of known bugs.

Refer to the CIAO bug pages for an up-to-date listing of known issues.

See Also

crates
copy_piximgvals, get_col, get_col_names, get_colvals, get_crate_item_type, get_crate_type, get_key, get_key_names, get_keyval, get_number_cols, get_number_rows, get_piximg, get_piximg_shape, get_piximgvals, get_transform, get_transform_matrix
transform
apply_transform, copy_transform, get_transform_type

Last modified: December 2013
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