casu_wcsutils

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

Functions
void	casu_xytoradec (cpl_wcs *wcs, double x, double y, double *ra, double *dec)
void	casu_radectoxy (cpl_wcs *wcs, double ra, double dec, double *x, double *y)
void	casu_xytoxy_list (cpl_wcs *wcs1, cpl_wcs *wcs2, int nc, double *x_1, double *y_1, double *x_2, double *y_2)
void	casu_radectoxieta (cpl_wcs *wcs, double ra, double dec, double *xi, double *eta)
int	casu_coverage (cpl_propertylist *plist, int fudge, double *ra1, double *ra2, double *dec1, double *dec2, int *status)
int	casu_crpixshift (cpl_propertylist *p, double scalefac, double sh[])
int	casu_rescalecd (cpl_propertylist *p, double scalefac)
int	casu_diffxywcs (cpl_wcs *wcs, cpl_wcs *wcsref, float *xoff, float *yoff, int *status)
int	casu_removewcs (cpl_propertylist *p, int *status)
int	casu_tabwcs (cpl_propertylist *p, int xcol, int ycol, int *status)

Detailed Description

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

Author

Jim Lewis, CASU

Function Documentation

casu_coverage()

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

extern

Name:

casu_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 casu status variable

Returns

Standard casu status variable

Author

Jim Lewis, CASU

Definition at line 345 of file casu_wcsutils.c.

References casu_xytoradec().

Referenced by casu_getstds(), and casu_imstack().

casu_crpixshift()

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

extern

Name:

casu_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 casu status variable

Author

Jim Lewis, CASU

Definition at line 464 of file casu_wcsutils.c.

Referenced by vircam_interleave().

casu_diffxywcs()

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

extern

Name:

casu_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 casu status variable

Returns

Standard casu status variable

Author

Jim Lewis, CASU

Definition at line 650 of file casu_wcsutils.c.

References casu_radectoxy(), and casu_xytoradec().

Referenced by vircam_jmp_dither_offsets().

casu_radectoxieta()

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

extern

Name:

casu_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 281 of file casu_wcsutils.c.

Referenced by casu_platesol().

casu_radectoxy()

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

extern

Name:

casu_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 151 of file casu_wcsutils.c.

Referenced by casu_diffxywcs(), casu_getstds(), and vircam_jmp_interleave().

casu_removewcs()

int casu_removewcs ( cpl_propertylist * p, int * status )

extern

Name:

casu_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 casu status variable

Returns

Standard casu status variable

Author

Jim Lewis, CASU

Definition at line 713 of file casu_wcsutils.c.

Referenced by casu_tabwcs(), vircam_jmp_save_catalogue(), and vircam_jmp_save_illum().

casu_rescalecd()

int casu_rescalecd ( cpl_propertylist * p, double scalefac )

extern

Name:

casu_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 casu status variable

Author

Jim Lewis, CASU

Definition at line 554 of file casu_wcsutils.c.

Referenced by vircam_interleave().

casu_tabwcs()

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

extern

Name:

casu_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 casu status variable

Returns

Standard casu status variable

Author

Jim Lewis, CASU

Definition at line 761 of file casu_wcsutils.c.

References casu_removewcs(), and casu_rename_property().

Referenced by imcore_conf().

casu_xytoradec()

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

extern

Name:

casu_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 93 of file casu_wcsutils.c.

Referenced by casu_coverage(), casu_diffxywcs(), casu_platesol(), vircam_jmp_interleave(), and vircam_jmp_wcsfit().

casu_xytoxy_list()

void casu_xytoxy_list ( cpl_wcs * wcs1, cpl_wcs * wcs2, int nc, double * x_1, double * y_1, double * x_2, double * y_2 )

extern

Name:

casu_xytoxy_list

Purpose:

Convert x,y on one frame to x,y on another

Description:

The WCS structures of two images is used to convert a list of x,y positions on one image to the frame of reference of the other

Language:

C

Parameters

wcs1	Input WCS structure for the first image
wcs2	Input WCS structure for the second image
nc	The number of input coordinates
x_1	Input X coordinate list
y_1	Input Y coordinate list
x_2	The output X coordinate list
y_2	The output Y coordinate list

Returns

Nothing

Author

Jim Lewis, CASU

Definition at line 212 of file casu_wcsutils.c.

Referenced by casu_pawsky_minus(), and vircam_grout().