18.21.1  Example 

     REAL X(5),Y(5),DX(5),DY(5)
     READ (1,'(4F10.0)') (X(I),Y(I),DX(I),DY(I),I=1,5)
     CALL TDJOIN(5,X,Y,DX,DY,1,64+4*512)
Reads  5 lines containing X,Y,DX,DY on each and joins the result with BLUE
dotted lines.  A single line segment joins each point.
     CALL TDJOIN(5,X,Y)
Joins  the  5  points  with the default line type (SOLID,WHITE).  The data
will be joined by multiple line segments to form a smooth curve.