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coordsys.setreferencelocation - Function

	Package	general
	Module	images
	Tool	coordsys

Set reference pixel and value

Synopsis
setreferencelocation(pixel, world, mask)

Arguments

pixel	in	New reference pixel
		Allowed:	Vector of integer
		Default:	Old reference pixel
world	in	New reference value
		Allowed:	Vector of doubles, vector of quantities, quantity of vector of doubles, vector of string, record
		Default:	Old reference value
mask	in	Indicates which axes to center
		Allowed:	Vector of boolean
		Default:	All

Returns
T or fail

Description

This function (short-hand name srl) sets the reference pixel and reference value to the specified values. The world coordinate can be specified in any of the formats that the output world coordinate is returned in by the toworld function.

You can specify a mask (argument mask) indicating which pixel axes are set (T) and which are left unchanged (F). This function will refuse to change the reference location of a Stokes axis (gets you into trouble otherwise).

This function can be rather useful when regridding images. It allows you to keep easily a particular feature centered in the regridded image.

Example

- cs := coordsys(linear=2)
- cs.referencepixel()
[1 1] 
- cs.referencevalue()
[0 0]
-
- w := cs.toworld([20,20], format='n')
- shp := [129,129]
- p := (shp-1)/2.0 + 1;
- cs.setreferencelocation (pixel=p, world=w)
- cs.referencepixel()
[65 65]  
- cs.referencevalue()
[19 19]