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Version 1.9 Build 1488 |
|
Package | general | |
Module | images | |
Tool | coordsys |
type | in | Which coordinate type ? | |
Allowed: | String from "direction", "stokes", "spectral", "linear", "tabular" or unset | ||
Default: | All | ||
value | in | Reference pixel | |
Allowed: | Vector of double |
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 srp) allows you to set a new reference pixel. You should not do this on "stokes" axes unless you are an adept or a big risk taker.
You can set the reference pixel either for all axes (type=unset) or for just the axes associated with a particular coordinate type.
Bear in mind, that if your Coordinate System came from a real image, then the reference pixel is special and you should not change it for Direction Coordinates.
You can recover the current reference pixel with function referencepixel.
- cs := coordsys(spectral=T, linear=2) - cs.setreferencepixel(value=[1.0, 2.0, 3.0]) - cs.referencepixel() [1 2 3] - - cs.setreferencepixel('lin', [-1, -1]) - cs.referencepixel() [1 -1 -1]