The NODER program permits interactive graphical editing of grid nodes prior to application of the triangulation algorithm in GRIDIT. It is useful for checking and modifying both depth and model grids while they are still in NODE format. Apart from basic editing operations such as adding, deleting and moving nodes, the NODER facilitates checking whether nodes are too close to one another, converting interior nodes into boundary nodes, or vice versa, and creating sets of interior nodes, according to certain rules, in selected parts of the model domain. The NODER also permits a fresh selection of boundary nodes to be made from the digitized boundary data.
In effect, the NODER provides the same facilities as programs NGHMESH and NODIT, and to some extent, those of SAMPLE, with some enhancements, but in an interactive graphics mode which gives the user far more flexible control of the final set of grid nodes to be passed on to the triangulation algorithm.