This program uses interactive graphics to allow examination and modification of an existing grid. At the end of an editing session, in addition to the modified grid, the Editor can output a triangle list and tables of certain triangle criteria. The Editor permits the user to display various properties of the grid, such as coordinates of individual vertices. It also provides means of displaying various properties of vertices and triangles which normally cannot be judged by eye. For instance, coloured markers can be placed at all vertices where water depth exceeds a specified value.
Changes can also be made to the grid. For instance, vertices and connections between vertices can be added or deleted; vertices can be moved or merged with one another; and triangle shape can be adjusted. The user directs changes in purely graphical terms, by suitable positioning of a cursor on the displayed grid; the Editor keeps account of all corresponding changes in vertex coordinates and interconnections between vertices. Any proposed changes are displayed immediately, for confirmation or cancellation.