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[Helena Mitasova]

Dear Grass users,

we have replaced s.surf.tps (program for interpolation
from point data using reg. spline with tension
and computation of topographic parameters)
on moon by a new version which has some changes to
make it more convenient to use.
For those already using s.surf.tps, please note
the following changes:
- aspect turned 180 deg to conform with the new
  version of r.slope.aspect
- you can define a mask so that the computation 
  is performed only in the area of interest
-parameters used for computation as well as 
 zmin,zmax for given data and interpolated surface
 are written to the history file
-changed defaults
-other minor changes
-more explanations have been added to manual page
 please, read the manual page before using the program
You will find the new s.surf.tps including the manual
at /grass/grass4.0/updates/src.alpha/sites/s.surf.tps.

We have also got a space for a column in GRASSClippings
journal called SURFACES AND MODELING, 
you can find more information on how to use s.surf.tps
in the Winter issue. 
For this column in the Spring issue, I am planning to overview new
development of tools for modeling of erosion,sediment transport
and deposition.  If you would like to contribute to
this column with a short description of your work in this area,
please, send me an email.

Merry Christmas, Happy New Year and many nice surfaces with splines

Helena Mitasova

helena at zorro.cecer.army.mil