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coordsys.referencepixel - Function

	Package	general
	Module	images
	Tool	coordsys

Recover the reference pixel

Synopsis
referencepixel(type)

Arguments

type	in	Coordinate type
		Allowed:	String from "direction", "stokes", "spectral", "linear", "tabular" or unset
		Default:	All

Returns
Vector of double or fail

Description

Each axis associated with the Coordinate System has a reference value, reference pixel and an increment (per pixel). These are used in the mapping from pixel to world coordinate.

This function (short-hand name rp) returns the reference pixel (in pixel axis order). You can recover the reference pixel either for all coordinates (leave type unset) or for a specific coordinate type (mimumum match of the allowed types will do). If you ask for a non-existent coordinate an exception is generated.

You can set the reference pixel with function setreferencepixel.

Example

- cs := coordsys(spectral=T, linear=2)
- cs.setreferencepixel([1.0, 2.0, 3.0])
- cs.referencepixel()
[1 2 3]  
-
- cs.referencepixel('lin')
[2 3]