fsaoi HEADAS help file

NAME

fsaoi -- Translate an SAOImage region file to an input file for FSELECT

USAGE

        fsaoi infile outfile

DESCRIPTION

This task reads a region file created by SAOImage, and translates it into the correct format for input to FSELECT. Since SAOImage's output is in pixel coordinates rather than the coordinates of the image file, FSAOI will translate the values using the keywords: CRVALn, CRPIXn and CDELTn, as well as the names of the columns corresponding to the axes of the image (XCOLNAME and YCOLNAME). The task F2DHISTO writes the correct values of these keywords in the primary array header. If keywords are missing from the primary header of the input imagefile, they can be supplied to this task via hidden parameters. The default hidden parameters correspond to no transformation. If the keywords are present in the image file, the hidden parameter values are ignored.

PARAMETERS

infile [filename]

The name of the ASCII SAOImage region file to be translated.

outfile [filename]

The name of the output FSELECT file.

imgfile [filename]

The name of the file containing the original image. This the header of this file contains all the information needed to translate SAOImage's pixel coordinate to the original file's coordinates. If this file is not available, or does not contain the correct keywords, the user will have to specify the values needed through hidden parameters.

(xcolname="X") [string]

The name of the column corresponding to the X axis of the original image.

(ycolname = "Y") [string]

The name of the column corresponding to the Y axis of the original image.

(crval1 = 1.) [real]

Coordinate value of X reference pixel

(crval2 = 1.) [real]

Coordinate value of Y reference pixel

(crpix1 = 1) [integer]

X axis reference pixel number

(crpix2 = 1) [integer]

Y axis reference pixel number

(cdelt1 = 1.) [real]

X axis coordinate increment

(cdelt2 = 1.) [real]

Y axis coordinate increment

EXAMPLES

1. Read the file saoimage.reg and write the appropriate FSELECT expression to the file fselect.in

          
               ft> fsaoi saoimage.reg fselect.in

BUGS

FSAOI will not produce correct results for images with different scale factors in the X and Y direction (CDELT1 .ne. CDELT2) if the selected region includes a rotation angle.