1 GRID_SG Optimum gridding of irregularly sampled data from an input table
        GRID_SG

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

    This task makes a cube from a table  containing irregularly sampled  da-
    ta.   The  data  is interpolated/extrapolated using a convolution taking
    into account the beam size of the observing telescope. The smoothing ef-
    fect  of  the  convolution  can  be  optionally removed by this task, by
    Fourier filtering. Fourier filtering is also used to suppress high  spa-
    tial  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 irregu-
    larly 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 al-
    low 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 ENDOFHELP







































