The educational software package WGVMAP has been developed to enable students to plot interactively the electric and magnetic field lines of TE and TM propagating modes in cylindrical waveguides. The waveguide cross-sections considered are rectangular, circular, sectoral, and circular with a conducting baffle. The vector field display and generation of the field lines can be performed on a very modest configuration of an IBM PC or compatible computer, and plotted on an x-y plotter. Examples are presented to demonstrate the interactive procedure for generating the field lines. >