DESCRIPTION is an Bourne Shell and Awk script. It is an interface between the external nnbathy utility and GRASS. nnbathy is a surface interpolation program provided with nn - a natural neighbor interpolation library, written by Pavel Sakov. provides 3 interpolation algorithms. According to nn library documentation these are: Delaunay interpolation (alg=l), Watson's algortithm for Sibson natural neighbor interpolation (alg=nn) and Belikov and Semenov's algorithm for non-Sibsonian natural neighbor interpolation (alg=ns). For performing the underlaying Delaunay triangulation in all cases nnbathy uses triangle software by Jonathan Richard Shewchuk.

The output raster map is a continous surface interpolated from the input or file data.


nnbathy, if built with '-DNN_SERIAL' (default as of nn 1.85), is able to create a grid of virtually any size. It interpolates and writes one output point at a time only. This eliminates the necessity to hold the whole output array in memory. However, even then all the input points are still held in the memory.

SEE ALSO (GRASS Add-on script)


Hamish Bowman, Otago University, New Zealand
Based on by Maciej Sieczka
nnbathy written by Pavel Sakov

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