[GRASSLIST:8373] EUCALLOCATION in GRASS?

[David Finlayson]

ArcInfo has a function called EUCALLOCATION (I think that's it) that I
am trying to duplicate in GRASS. I don't know if there is a single
command or a smart way to do this, but I don't have any efficient
ideas.

The EUCALLOCATION function takes a categorical raster as input. Any
null cells are assigned the category value of the nearest known value
based on euclidean distance (hence the name). You can work with
floating point values by converting them to integer "categories". This
is useful for extrapolating into null areas without changing the value
of the last known good point.

I do wave modeling and sometimes the shoreline in the model doesn't
match up with higher resolution bathymetry in GRASS. So I wind up with
waves that are breaking well seaward of the real shoreline. What I
want to do is extrapolate the wave values from the low-resolution data
shoreward to the beach on the high resolution model. I don't want to
change the values in those last known good cells using a neighborhood
function, just "move" them shoreward and fill in the data gap.

Any ideas on how to do this?

David
--
David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
Seattle, WA  98195-7940
USA

Office: Marine Sciences Building, Room 112
Phone: (206) 616-9407
Web: http://students.washington.edu/dfinlays