For the rectangular field target type only one source can bespecified. This option is enabled by selecting 1 rectangular field which will then create a panel called Rectangle withinwhich the fields to specify the parameters for the rectangle can bespecified. The parameters of the rectangle include the relative orabsolute position, its length, width and position angle.
The rectangle parameters can also be specified via the rectangularshape icon on top of the image display window. When clicking thisbutton the cursor can be used to create a rectangle and to determinethe position, size and position angle - the rectangle can be resizedby the blue handles and can be rotated by the green handle. Theparameters of the rectangle also fill the fields in the form at theright. Spacing is the angular distance between the positions ofthe individual pointing, specified either in angular units or infraction of the synthesized beam. The default is to use half of theantenna beamsize (field of view) which is equivalent to Nyquistsampling.
Clicking the Show pointing positions button if a rectangulararea has been defined will cause pointing positions to be displayed.Be sure that the Spacing parameter is set or else nothing willhappen. The display can be toggled on and off with this button. Thefigures presenting the positions are not selectable, but they areupdated following the actions of move, resize and rotate to therectangle. To hide the circles representing the field of view, uncheck Show FOV(circle) in the FOV Parameters panel below theimage.