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<TITLE>RE: [GRASS-user] r.texture NULL value error</TITLE>
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<P><FONT SIZE=2>It seems that r.null missed some NULL values or some negative values are still there (one or both issues may be the cause).<BR>
<BR>
Anyway I worked around it by adding a fixed amount with the map calculator and rescaling it to the wanted scale.<BR>
<BR>
This workaround seems to be foolproof and confirms that there must be a NULL value or a negative value that is missed by the summary statistics and r.null causing r.texture to go into spasm.<BR>
<BR>
So, it's fixed and not fixed at the same time. Maybe I'll look into the code later.<BR>
<BR>
Cheers,<BR>
Koen<BR>
<BR>
<BR>
-----Oorspronkelijk bericht-----<BR>
Van: neteler.osgeo@gmail.com namens Markus Neteler<BR>
Verzonden: ma 24-11-2008 15:46<BR>
Aan: Hufkens Koen<BR>
CC: GRASS user list<BR>
Onderwerp: Re: [GRASS-user] r.texture NULL value error<BR>
<BR>
On Mon, Nov 24, 2008 at 2:39 PM, Hufkens Koen <koen.hufkens@ua.ac.be> wrote:<BR>
> Hi list,<BR>
><BR>
> I've been trying to run a r.texture filter on a map but I constantly get the<BR>
> error:<BR>
><BR>
> ERROR: Negative or no data pixel found. This module is not yet able to<BR>
> process no data holes in a map, please fill with r.fillnulls or<BR>
> other algorithms<BR>
><BR>
<BR>
I ran into this myself a few minutes ago :)<BR>
The trick is that *all* pixels in the current region are need to be<BR>
set to non-NULL.<BR>
If NULL pixels are present, r.texture fails.<BR>
<BR>
run<BR>
r.univar mapname<BR>
to see how many NULL cells are in the current region.<BR>
<BR>
Solution:<BR>
- either zoom into area without NULL pixels (won't always make sense)<BR>
- or fill the NULL areas with some value (various options)<BR>
- (or fix r.texture if possible).<BR>
<BR>
Markus<BR>
<BR>
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