Parabolic DEM Estimator

[Sidey Timmins]

Hi Grass-users/ Fellow algorithm designers!

    Does anyone know the best parabolic estimator (data is raster
digital elevation model) for the center cell with 8 neighbours?


                     1        2        3

                     4        ?        6

                     7        8        9


What elevation is cell 5 (marked ?) given the other DEM cell values?
The problem seems to be related to the prior estimation of aspect
and dip directions so the parabolic estimation can be done in the
DIP direction.


                   Thank-you in advance.       Sidey Timmins
                   stq at ornl.gov     (615)576-5546
                                    (615)576-8543 (FAX)