^[a] Note that these function require input from a sla file.

^[b] Contour filling is currently very, very rudimentary. The The zero level is a baseline and contours are filled downwards to -ive and then upwards to +ive. The upshot is that for re-entrant contour levels the contour will (a) be filled one color in the wrong direction and (b) be overwritten by the nearest local maxima/minima of the reentrant curve portion. You have been warned!

^[c] Contour filling will not be apparent unless PLOTX or PREVUE are invoked with the "color fill" option.

^[a] These items are mandatory.

^[b] Codes nc , start , and incr are not allowed for the direct option - follow the direct flag on the input line with the levels desired. The levels line can function in a cumulative manner for the direct option. The negate and zincl operations are not performed until all line input is complete.

^[a] The n is the first line and m the last line to be assigned to this type. Both n and m must be input. The lines are assigned sequentially. Options can be input in any order and in any combination of line types.