  The presented work is part of a larger research program dealing with
developing tools for coupling biogeochemical models in contaminated landscapes.
The specific objective of this article is to provide the researchers a tool to
build hexagonal raster using information from a rectangular raster data (e.g.
GIS format), data porting. This tool involves a computational algorithm and an
open source software (written in C). The method of extending the reticulated
functions defined on 2D networks is an essential key of this algorithm and can
also be used for other purposes than data porting. The algorithm allows one to
build the hexagonal raster with a cell size independent from the geometry of
the rectangular raster. The extended function is a bi-cubic spline which can
exactly reconstruct polynomials up to degree three in each variable. We
validate the method by analyzing errors in some theoretical case studies
followed by other studies with real terrain elevation data. We also introduce
and briefly present an iterative water routing method and use it for validation
on a case with concrete terrain data.
