Picking item INTERIOR in brings up the following sub-menu of operations possible on individual interior nodes:
The first three options in this sub-menu permit editing of individual interior nodes.
Option ADD allows addition of a single interior node. The user is prompted to indicate the required position for the new node by means of the cursor. A coloured marker is placed at the specified position and the user is asked to confirm the addition. On confirmation, the following prompt appears:
and the user can then enter an appropriate depth, if known, or set the depth to zero by pressing RETURN.
The DELETE option allows deletion of any individual interior node. A choice of methods of selecting the node to be deleted is offered in the right hand panel. The user has to confirm the proposed deletion before the node file is actually updated. When selecting nodes by their indices, it is best to tackle the nodes in reverse order (highest index first), since node indices higher than that of the node deleted are decremented as soon as the deletion of a node is confirmed.
The MOVE option is equivalent to a DELETE followed by an ADD. The node to be moved and its new position are selected with the cursor.
The DISPLAY option provides control over windowing and appears in many
NODER sub-menus. It is described in detail in DISPLOT.
See Section 
The INFO option permits viewing and changing of various node attributes, as detailed in the section {TOP}INFO.