Documentation on imgen

Task: imgen
Purpose: All-purpose image manipulator/creator
Categories: utility, map manipulation

        IMGEN is a MIRIAD task which modifies an image, or creates a new
        image. 

Key: in
        The input image, which is to be modified. The default is a map
        with one plane which consists entirely of zeros. 

Key: out
        The name of the output image. No default. The output image has the
        same characteristics as the input image, if present. If no input
        image is given, the `imsize', `cell' and `radec' keywords give the
        characteristics of the output.

Key: factor
        Factor to multiply the input image by. This is meaningless if no
        input image is given. The default is 1. 

Key: object
        This determines the type of objects added to the input image.
        Several objects can be given (the objects can be the same type, or
        different), and minimum match is supported. Possible objects are:
           level      An offset (DC) level.
           noise      Noise (gaussian distribution).
           point      A point source.
           gaussian   An elliptical or circular gaussian.
           disk       An elliptical or circular disk.
           j1x        A J1(x)/x function
           shell      2D projection of an optically-thin spherical shell

Key: spar
        Parameters which give the characteristics of the object. The
        parameters are given as a sequence of values, with one to six
        values needed per object (depending on the object type). When
        there are multiple objects, the parameter value for the second
        object follow those for the first object, etc. The values are
        as follows:
          Object Type           SPAR values
          -----------           -----------
           level                  offset
           noise                  rms
           point                  amp,x,y
           gaussian               amp,x,y,bmaj,bmin,pa
           disk                   amp,x,y,bmaj,bmin,pa
           j1x                    amp,x,y,bmaj,bmin,pa
           shell                  amp,x,y,bmaj
        Here offset is the offset level, "rms" is the rms value of
        the noise, "amp" is the normally peak value of the object (but
        see options=totflux below), "x" and "y" are the offset positions (in
        arcsec) of the object relative to the reference pixel, "bmaj" and
        "bmin" are the major and minor axes FWHM (in arcsec), and "pa" is
        the position angle of an elliptical component (in degrees). The
        position angle is measured from north towards east.
        The default is an object of unit amplitude, at the reference pixel,
        with a FWHM of 5 arcsec.

Key: imsize
        If not input image is given, then this determines the size, in
        pixels, of the output image. Either one or two numbers can be
        given. If only one number is given, then the output is square.
        The default is 256 pixels square. 

Key: cell
        The increment between pixels, in arcseconds. This is only used if
        there is no input map. The default is 1 arcsec.

Key: radec
        If no input image is given, this gives the RA and DEC of the
        image, in hours and degrees, respectively. They can be given in
        hh:mm:ss,dd:mm:ss, or as decimal hours and degrees. The default is
        RA=0, DEC=45.

Key: options
        Extra processing options. Several can be given, separated by
        commas. Minimum match is used. Possible values are:
          totflux  Interpret the "amp" values in the spar keyword as
                   total integrated flux densities (Normally the "amp"
                   parameters are interpretted as peak values).