[GRASS-user] How can I remove steps artefacts in digital elevation model?

[bonushenricus]

Hello everyone
I have a problem with an artefact in the dem I build from the data as a
geopackage here
https://www.dropbox.com/scl/fi/7vzgupxszpg2sw7ib08p4/point_survey.gpkg?rlkey=7u1bv3rx8vcvkruq6z8zeezf0&dl=0
the problem has already described here
https://www.mail-archive.com/grass-user@lists.osgeo.org/msg40869.html
in which I had operated with
"v.surf.rst --overwrite input=point_survey zcolumn=z elevation=dem
mask=MASK tension=36. smooth_column=rms segmax=500 npmin=600 dmin=0.5
dmax=5"
First of all I deleted dmax from v.surf.rst.
Now I have tried raising the tension, even by a lot, but it does not
change.
I tried lowering the tension, but the steps still occur.
Then I tried v.surf.rst on a higher resolution, at 5 cm, and then
resample to 20 cm. I tried with r.resample.interpol, r.resample.rst and
r.resample.tsp, with various parameters, various interpolation methods,
various tensions or various smoothness indices, but I was unable to
create a profile without these artefacts, which are in the order of
only a few centimetres, but enough to create problems in the simulation
with r.sim.water.
I finally tried another approach: I created the contours, transformed
the vector to raster, at a resolution of 5 cm (to get thin contours)
and then used r.fillnulls to a 20 cm resolution region. With method=rst
(which is the default) it gives me an error:
"Growing NULL areas
Assigning IDs to NULL areas
Processing 1 map holes
Filling hole 1 of 1
ERROR: Invalid input <n=n+0>"
With method=bicubic it works but makes the steps.
r.resample.bspline create other artefacts at the limit of the
calculation regions.
I should probably try anisotropy in v.surf.rst?
Anyone have a solution?

Thank you thank you!!
-- 
-- 
Perito agrario Enrico Gabrielli
progetto F.A.R.M. www.farm-agroecologia.it
Tessera n. 633 Collegio Periti agrari prov. Di Modena
Biblioteca agricoltura: https://www.zotero.org/groups/aplomb/
https://www.inaturalist.org/observations/bonushenricus