[GRASS-user] r.neighbors with large neighborhoods

GRASS GRASS user
1

I'm working landform analysis using r.neighbors. The help file says that "size" can go up to 25 (or +/1 12 pixels). I need much bigger neighborhoods than that, so I just entered a large number and it seems to work (although it's slow). Does anybody know what the true limits of the r.neighbors code really is?

Thanks, Dave
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2

Dave Roberts wrote:

I'm working landform analysis using r.neighbors. The help file says
that "size" can go up to 25 (or +/1 12 pixels). I need much bigger
neighborhoods than that, so I just entered a large number and it seems
to work (although it's slow). Does anybody know what the true limits of
the r.neighbors code really is?

There isn't a fixed limit.

At one time the size= option had an associated list of acceptable
values. The reason for this was to have the parser perform the check
to ensure the value was odd, by specifying "1,3,5,7,..." as acceptable
values. The limit was merely a consequence of the fact that such a
list has to be finite.

The list has long since been removed (the even/odd check is coded
explicitly). I can't find any mention of the limit in the manual page;
which version are you using?

--
Glynn Clements <glynn@gclements.plus.com>