1 GRID_SG
        GRID_SG

    Optimum image reconstruction from irregularly sampled data  with  finite
    angular resolution.

    This task makes a cube from  a  table   containing  irregularly  sampled
    data.   The data is interpolated/extrapolated using a convolution taking
    into account the beam size of the  observing  telescope.  The  smoothing
    effect  of  the  convolution  can be optionally removed by this task, by
    Fourier filtering. Fourier filtering  is  also  used  to  suppress  high
    spatial frequency noise. The resulting image is thus optimal in terms of
    signal to noise and angular resolution.

    In mode NATURAL,  a  convolution  kernel  is  used  to  interpolate  the
    irregularly sampled data using the weight of each individual point.

    In mode UNIFORM, the same convolution process is used but the individual
    points are assumed to have equal weight.

    The pixel size is specified by the user, but the map size is  determined
    by  the task.  The input  table can be created by command GRID in CLASS,
    or using task TABLE from a formatted file.

2 TABLE$
        TASK\CHARACTER "Input TABLE name" TABLE$

    Specify the name of the input table.

2 MAP$
        TASK\CHARACTER "Output MAP name" MAP$

    Specify the name of the output map. The output map will be in VLM  order
    (Velocity, X coordinate, Y coordinate).

2 XCOL$
        TASK\INTEGER "Column of X coordinates" XCOL$

    Specify the column of the table containing the X coordinates

2 YCOL$
        TASK\INTEGER "Column of Y coordinates" YCOL$

    Specify the column of the table containing the Y coordinates

2 WCOL$
        TASK\INTEGER "Column for weights" WCOL$

    Specify the column containing the weights

2 MCOL$
        TASK\INTEGER "First and last column to grid" MCOL$[2]

    Specify the first and last column to be regridded. Note that the  weight
    column  can  be  included  in order to produce a weight image.  This can
    allow further processing based on Signal-to-Noise ratio.

2 WEIGHT_MODE$
        TASK\CHARACTER "Gridding Mode (NAtural or UNiform)" WEIGHT_MODE$

    Indicate the weight mode. NATURAL indicates a  convolution  with  proper
    weighting, UNIFORM a convolution without weighting.

2 TOLE$
        TASK\REAL "X-Y position tolerance" TOLE$

    Positional tolerance. Points separated less than TOLE$  (on  each  axis)
    are added together before resampling.

2 BEAM$
        TASK\REAL "Primary Beam Size" BEAM$

    Size of the beam used to obtain the data (in user units, not in pixels)

2 DIAM$
        TASK\REAL "Antenna diameter"  DIAM$

    Antenna diameter to be use in the   Fourier  filtering  process.  Higher
    spatial frequencies are filtered out completely.

2 MIN_WEIGHT$
        TASK\REAL "Minimum weight"  MIN_WEIGHT$

    Minimum relative weight under  which  pixels  in  the  final  image  are
    blanked.

2 GRID$
        TASK\LOGICAL "Correct for gridding ?" GRID$

    Indicate whether the smoothing effect of the convolution  kernel  should
    be corrected or not before producing the final image.

1 END