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

[Blumentrath, Stefan]

OK, I shall do that...

-----Original Message-----
From: Helena Mitasova [mailto:hmitaso at ncsu.edu] 
Sent: 23. april 2013 15:19
To: Blumentrath, Stefan
Cc: GRASS developers list
Subject: Re: [GRASS-dev] Grass 7: segmax and npmin confused in r.fillnulls / v.surf.rst

Stefan,

I think you should file a ticket for this,

Helena 

On Apr 22, 2013, at 4:37 AM, SBL wrote:

> 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?
> 
> 
> 
> 
> --
> View this message in context: 
> http://osgeo-org.1560.x6.nabble.com/Grass-7-segmax-and-npmin-confused-
> in-r-fillnulls-v-surf-rst-tp5048683.html
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