[GRASS-user] r.mfilter produces empty result

[Markus Neteler]

On Thu, May 11, 2017 at 5:05 PM, Luí­s Moreira de Sousa
<luis.de.sousa at protonmail.ch> wrote:
> Thank you Anna, indeed with TYPE P it works correctly.
>
> My first question is why is it in the book with TYPE S? That way it does not
> seem to be a high-pass filter at all...

Indeed. Two things:

- you were reading the oldish 1st edition of the book from 2002 while
there is the fancy 3rd edition from 2008 :-)
- The erratum was noted here back then:
https://grassbook.org/errata/errata-1st-edition

> I also find the definition of the sequential filter somewhat unclear. Not
> sure what it does, but certainly can not be used with high-pass or low-pass
> filters.

Likely something to improve in the manual page of r.mfilter.

HTH,
Markus


-- 
Markus Neteler, PhD
http://www.mundialis.de - free data with free software
http://grass.osgeo.org
http://courses.neteler.org/blog