Abstract – Pointwise geological initial data in are used for creating hydrogeological models (HM). By processing in by interpolation methods, - maps are created on (x, y) – grids of HM. The maps represent geometrical and physical features of geological layers. If solutions of boundary field problems are applied as interpolation results ( - maps) then in serve as the boundary conditions of the first kind. They must be joined to nodes of the interpolation grid. In this paper, three methods are compared that may be applied to perform this task when the local date search region is a square, a circle, an area enclosed by hyperbola arcs. Features of these methods are examined and recommendations on their optimal use are given.