function maskme,maskproc,win,datp=datp

                LAMP function to mask the unwanted points from a workspace

 NECESSARY VARIABLES

                maskproc=a string with the mask procedure and relevant parameters

                                The available mask procedures are:

                                box:         needs a 2- or 4-element array to define the box

                                            for a 2 element array, the limits are [xmin,xmax]
                                                for a 4 element array, the limits are [xmin,xmax,ymin,ymax]

                                circle:      needs a 3-element array with centreX, centreY, radius

                                ellipse:needs a 4-element array with Xlocus, Ylocus, centreX, centreY

                win=input workspace

OPTIONAL VARIABLES

                datp = the data structure for the workspace

                                If unspecified, the program will take the data structure from the workspace

                e.g. type at lamp interface:

                                w2=maskme('box,[190,200,63,222]',w1)