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Last modified: December 2006

URL: http://cxc.harvard.edu/ciao3.4/set_ignore2d.html
Hardcopy (PDF): A4 | Letter
AHELP for CIAO 3.4 set_ignore2d Context: sherpa

Synopsis

Module functions for ignoring source and background regions in 2-D datasets.

Syntax

Integer_Type set_ignore2d([Integer_Type],String_Type[,String_Type])
Integer_Type set_signore2d([Integer_Type],String_Type[,String_Type])
Integer_Type set_bignore2d([Integer_Type],String_Type[,String_Type])

Success/Error Return Values: 1/0

Arguments:

(1) Dataset number (default 1)

(2) A filter expression: <filterExpr>

(3) The coordinate system expression

Description

The commands set_ignore2d, set_signore2d, and set_bignore2d allow the user to specify regions to ignore in both source and background datasets, a source dataset, or a background dataset respectively. These functions may only be applied to 2-D data. Use set_ignore to set ranges to ignore in 1-D spectra.

See the Sherpa Filtering Chapter for the full definition of <filterExpr>. (Also see examples below.)

The default coordinate system expression is "logical" (i.e., image coordinates). Allowed coordinate system expressions include:

  • "logical" | "image" - image coordinates
  • "physical" - physical coordinates
  • "wcs" | "world" - world coordinates

See the related Sherpa commands NOTICE and IGNORE for more information.

Example 1

Read in an image; ignore the central source using a circular exclude region:

sherpa> load_image(2,"example_img.fits") 
1
sherpa> set_ignore2d(2,"circle(247,257,20)")
1

In this example, all data within a radius of 20 pixels of the image coordinate (247,257) are ignored.

Example 2

Apply a box filter to an image in physical coordinates:

sherpa> load_image(1,"example_img2.fits")
1
sherpa> set_ignore2d(,"box(4050,3920,30,30)","physical")
1

Bugs

See the Sherpa bug pages online for an up-to-date listing of known bugs.

Hardcopy (PDF): A4 | Letter
Last modified: December 2006



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