vircam_wcsutils
[Groups of Support Routines]

Detailed Description

These are support routines used for defining and manipulating image and table world coordinate system information.

Author:
Jim Lewis, CASU


Functions

void vircam_xytoradec (cpl_wcs *wcs, double x, double y, double *ra, double *dec)
void vircam_radectoxy (cpl_wcs *wcs, double ra, double dec, double *x, double *y)
void vircam_radectoxieta (cpl_wcs *wcs, double ra, double dec, double *xi, double *eta)
int vircam_coverage (cpl_propertylist *plist, int fudge, double *ra1, double *ra2, double *dec1, double *dec2, int *status)
int vircam_crpixshift (cpl_propertylist *p, double scalefac, double sh[])
int vircam_rescalecd (cpl_propertylist *p, double scalefac)
int vircam_diffxywcs (cpl_wcs *wcs, cpl_wcs *wcsref, float *xoff, float *yoff, int *status)
int vircam_removewcs (cpl_propertylist *p, int *status)
int vircam_tabwcs (cpl_propertylist *p, int xcol, int ycol, int *status)

Function Documentation

int vircam_coverage ( cpl_propertylist *  plist,
int  fudge,
double *  ra1,
double *  ra2,
double *  dec1,
double *  dec2,
int *  status 
)

Name:
vircam_coverage
Purpose:
Get coverage in ra,dec of a frame
Description:
Given a property list (presumably from an input FITS image) this routine works out the min and max equatorial coordinates covered by the image.
Language:
C
Parameters:
plist Input property list
fudge Percentage fudge factor
ra1 Lower RA
ra2 Upper RA
dec1 Lower Dec
dec2 Upper Dec
status Standard input and output vircam status variable
Returns:
Standard vircam status variable
Author:
Jim Lewis, CASU

Definition at line 286 of file vircam_wcsutils.c.

References vircam_xytoradec().

Referenced by vircam_getstds().

int vircam_crpixshift ( cpl_propertylist *  p,
double  scalefac,
double  sh[] 
)

Name:
vircam_crpixshift
Purpose:
Shift and scale the values of CRPIXn in a header
Description:
The values of CRPIXn are rescaled by a given factor and offset by a given value for each axis. This will fail for anything other than 2d images. This routine is useful for output images that have been resampled and shifted. The axes will be transformed in the following way: crpixnew[i] = (crpixold[i] - sh[i])/scalefac - 1.0;
Language:
C
Parameters:
p The property list defining the header for the file. This must have a valid FITS WCS.
scalefac The scaling factor for both axes.
sh The shift for both axes
Returns:
Standard vircam status variable
Author:
Jim Lewis, CASU

Definition at line 403 of file vircam_wcsutils.c.

Referenced by vircam_interleave().

int vircam_diffxywcs ( cpl_wcs *  wcs,
cpl_wcs *  wcsref,
float *  xoff,
float *  yoff,
int *  status 
)

Name:
vircam_diffxywcs
Purpose:
Work out the cartesian offsets between two images using their WCSs
Description:
The wcs of two images is used to define the cartesian offsets between them. The sense of the offset is that xoff = xprog - xref.
Language:
C
Parameters:
wcs The wcs structure of the programme image
wcsref The wcs structure of the reference image
xoff The X offset
yoff The Y offset
status Standard input and output vircam status variable
Returns:
Standard vircam status variable
Author:
Jim Lewis, CASU

Definition at line 590 of file vircam_wcsutils.c.

References vircam_radectoxy(), and vircam_xytoradec().

Referenced by vircam_jmp_dither_offsets().

void vircam_radectoxieta ( cpl_wcs *  wcs,
double  ra,
double  dec,
double *  xi,
double *  eta 
)

Name:
vircam_radectoxieta
Purpose:
Convert ra,dec --> xi,eta
Description:
A WCS structure is used to convert input equatorial coordinates to standard coordinates
Language:
C
Parameters:
wcs Input WCS structure
ra Input RA
dec Input Dec
xi Output xi in radians
eta Output eta in radians
Returns:
Nothing
Author:
Jim Lewis, CASU

Definition at line 221 of file vircam_wcsutils.c.

Referenced by vircam_platesol().

void vircam_radectoxy ( cpl_wcs *  wcs,
double  ra,
double  dec,
double *  x,
double *  y 
)

Name:
vircam_radectoxy
Purpose:
Convert ra,dec --> x,y
Description:
A WCS structure is used to convert input equatorial coordinates to x,y.
Language:
C
Parameters:
wcs Input WCS structure
ra Input RA
dec Input Dec
x Output X
y Output Y
Returns:
Nothing
Author:
Jim Lewis, CASU

Definition at line 162 of file vircam_wcsutils.c.

Referenced by vircam_diffxywcs(), vircam_getstds(), and vircam_jmp_interleave().

int vircam_removewcs ( cpl_propertylist *  p,
int *  status 
)

Name:
vircam_removewcs
Purpose:
Remove FITS image WCS keywords from a propertylist
Description:
Remove FITS WCS keywords from a propertylist. This is sometimes necessary if a FITS table header has been based on an image header.
Language:
C
Parameters:
p The input propertylist
status Standard input and output vircam status variable
Returns:
Standard vircam status variable
Author:
Jim Lewis, CASU

Definition at line 653 of file vircam_wcsutils.c.

Referenced by vircam_tabwcs().

int vircam_rescalecd ( cpl_propertylist *  p,
double  scalefac 
)

Name:
vircam_rescalecd
Purpose:
Scale the values of the CD matrix
Description:
The values of CDi_j are rescaled by a given amount each. The elements will each be multiplied by the same given scale factor. This routine is useful for output images that have been resampled.
Language:
C
Parameters:
p The property list defining the header for the file. This must have a valid FITS WCS.
scalefac The scaling factor for both axes.
Returns:
Standard vircam status variable
Author:
Jim Lewis, CASU

Definition at line 494 of file vircam_wcsutils.c.

Referenced by vircam_interleave().

int vircam_tabwcs ( cpl_propertylist *  p,
int  xcol,
int  ycol,
int *  status 
)

Name:
vircam_tabwcs
Purpose:
Remove FITS image WCS keywords from a propertylist and replace with tabular keywords
Description:
Replace the FITS image WCS keywords in a propertylist with the relevant table FITS keyword. This is not very general
Language:
C
Parameters:
p The input propertylist
xcol The column number for the X position
ycol The column number for the Y position
status Standard input and output vircam status variable
Returns:
Standard vircam status variable
Author:
Jim Lewis, CASU

Definition at line 701 of file vircam_wcsutils.c.

References vircam_removewcs(), and vircam_rename_property().

void vircam_xytoradec ( cpl_wcs *  wcs,
double  x,
double  y,
double *  ra,
double *  dec 
)

Name:
vircam_xytoradec
Purpose:
Convert x,y -> ra,dec
Description:
A WCS structure is used to convert input x,y coordinates to equatorial coordinates.
Language:
C
Parameters:
wcs Input WCS structure
x Input X
y Input Y
ra Output RA
dec Output Dec
Returns:
Nothing
Author:
Jim Lewis, CASU

Definition at line 103 of file vircam_wcsutils.c.

Referenced by vircam_coverage(), vircam_diffxywcs(), vircam_jmp_interleave(), vircam_jmp_wcsfit(), and vircam_platesol().

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