Picking ADD/DEL brings up the following sub-menu:
Option LINE in the above sub-menu permits addition of a connection between two vertices. It brings up the following right-hand panel:
By picking options (1) to (3), the user can designate the nodes to be joined by entering their indices or coordinates via the keyboard or Picking them with the cursor. In this, as in all active editing operations reached through menu {TOP.EDIT}, with the sole exception of {TOP.MENU}RESHAPE, the proposed change to the grid is displayed to the user for confirmation or cancellation before any permanent change is made to the grid file.
Note: When selecting a node by means of the cursor, the message:
may be displayed. When this happens, a second attempt to select the required node will normally prove successful, since the cursor range is increased automatically. The cursor range can also be set directly as described in {TOP.CONFIG}CURSOR.
Choice of option VERTEX in permits the user to add a new vertex to the grid and connect it to selected neighbours. At the prompt "Pick new vertex", the user should use the cursor to position the new vertex. In this case, the right-hand information panel appears as follows:
After the new vertex has been chosen, the user uses option (1) from the panel to designate each of the existing nearby vertices to which the new vertex is to be connected. When all the required neighbours of the new vertex have been indicated in this way, select DONE. Prompts remind the user to set water depth and the computational code at the new vertex, and to reset computational codes of the neighbours, where necessary.
Option LINE in this sub-menu permits deletion of an existing connection between two vertices. The user is prompted to place the cursor at the mid-point of the line to be deleted.
Option VERTEX in {TOP.EDIT.DELETE} allows deletion of a vertex and its connections to other vertices.
The DISPLAY option provides control over windowing and is described in
detail in the section on menu {TOP.DISPLAY} in DISPLOT.
See Section 