[GRASS-dev] Grass 7: segmax and npmin confused in r.fillnulls / v.surf.rst

[SBL]

Hi

I am struggeling a bit with r.filnulls on a big raster (60,000 x 50,000
cells) with lots of "NULL" areas (ca. 52,000 holes).

In trac I provided a patch for speeding-up r.fillnulls ( #1938
<http://trac.osgeo.org/grass/ticket/1938>  ). But it still feels pretty slow
on such a big raster...

In particular, I was stumbeling upon the following waring message



If number of points is below 600, then both segmax and npmin are set to
"pointsnumber". So, from r.fillnulls segmax was set to 40 (and not 80, like
the warning message indicates...). Then I tested in v.surf.rst with a hole
with 1033 existing data points on the edge, and now I am a little confused:

If I set 

I get the following Warning message:

And interpolation is done within 6 seconds.

I get the same message if I set:

But now processing takes now 16 seconds...

The warning message above changes to 

when I set:

Strange that it is possible because in the GUI it says npmin has to be
greater than segmax...
But processing time is down on 6 secs again...

With:

I get the expected error message, that npmin has to greater than segmax.

Finally, I set segmax and npmin to the "default" in r.fillnulls for holes
with pointnumber >= 600:

Now processing takes 55 seconds!!!
This is especially confusing because during the tests with npmin = 1033 I
got the following warning message in addition:

But actually, processing was nearly 10 times faster then with npmin=300!

Sorry for the long post!

Summary:
Something seems to be confused in the way v.surf.rst handles the user input
and gives warning/error messages...


Shall I file a ticket?


Cheers
Stefan

P.S.: BTW, using the "dmin" in r.fillnulls could improve the processing
speed for bigger holes some more. Maybe it is worth giving the user the
option to set dmi also in r.fillnulls?




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