function Fl_Combine, Flines1, Flines2 ;+ ; NAME: Fl_Combine ; Purpose: ; Comine two field line structures into one field line structures ; Calling Sequence: ; Flines = Fl_Combine (Flines1, Flines2) ; Input: ; Flines1 A structure variable represening a set of field lines ; This variable has the following tags ; 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. ; Flines2 Another varibale ; Output: ; Flines A New field line structure reprsenting all the field lines ; in Flines1 and Flines2 ;- n1 = Flines1.Nlines pos1 = Flines1.Pos data1 = Flines1.Data n2 = Flines2.Nlines pos2 = Flines2.Pos data2 = Flines2.Data n = n1+n2 pos=lonarr(n+1) pos(0:n1-1) = pos1(0:n1-1) pos(n1:n) = pos2+pos1(n1) data = fltarr(3, pos(n)) data(*, 0:pos(n1)-1)=data1 data(*, pos(n1):pos(n)-1) =data2 Flines = {Nlines:n, Pos:pos, Data:data} return, Flines end