Various interactive and non-interactive operations in the TRIGRID package produce deterioration in the accuracy of depth values at vertices of the model grid. For example in most editing steps using the interactive Editor, depths are updated by linear interpolation among depth values at existing grid vertices. This leads to noticeable errors in depth if the same vertex is involved repeatedly. In such situations, it is advisable to re-evaluate depths at the model grid vertices by a fresh interpolation from the reference depth grid developed in DEPGRID. This is the purpose of Program REDEP. Both the grid whose depths are to be re-evaluated and the reference depth grid are in NEIGH format.