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Last modified: December 2009

URL: http://cxc-newtest.cfa.harvard.edu/ciao4.2/pix_chip_to_gdp.html
AHELP for CIAO 4.2

pix_chip_to_gdp

Context: pixlib

Synopsis

Convert from the Chip to Grating Dispersion Plane (GDP) coordinate system.

Syntax

Array_Type pix_chip_to_gdp( Integer_Type chip_id, Double_Type x,
Double_Type y )

Description

This routine converts a position in the Chip coordinate system to the matching position in the Grating Dispersion Plane (GDP) coordinate system, using the current settings of the pixlib module. The inputs are chip ID (the ccd_id value for ACIS and chip_id value for HRC data) and the chip location (x,y) in pixels. The return value is a two-element array which gives the GDP coordinates in pixels.

The pixlib module is not available by default; to use it in a S-Lang program, it must be loaded using the S-Lang require() function:

  require("pixlib");

Example

slsh> require( "pixlib" );
slsh> pix_init_pixlib;
slsh> pix_set_detector( "HRC-S" );
slsh> gdp = pix_chip_to_gdp( 2, 512, 512 );
slsh> print( gdp );
41331.4
17286.2

Using the default settings of the pixlib module for the HRC-S detector (i.e the aimpoint is on HRC-S2), we find that the chip position (512,512) on HRC-S2 corresponds to the location (41331.4,17286.2) in the GDP system.

Bugs

See the bugs page for the pixlib library on the CIAO website for an up-to-date listing of known bugs.

See Also

modules
pixlib
pixlib
pix_chip_to_fpc, pix_chip_to_tdet, pix_fpc_to_chip, pix_fpc_to_gdp, pix_fpc_to_msc, pix_tdet_to_chip

Last modified: December 2009