function fl_str, dummy ;+ ; Name : fl_str ; ; Purpose : Initializing the field lines structures ; ; Calling Sequence : ; flines = fl_str() ; ; Inputs : ; None ; Output : ; flines : data structure defining a set of field lines, ; having the structure fields ; ; nlines : # of field lines in the set ; pos : an index array with (nlines+1) elements ; data : a 2-D array of 3 x pos(nlines) elements ; the 1st field line : from pos(0) to pos(1)-1 ; the 2nd filed line : from pos(1) to pos(2)-1 ; and so on. ; ; ;- return, {nlines:1, $ pos: [0, 2], $ data: replicate(0, 3,2)} end