[GRASS-user] Fuzzy logic in GRASS

[Jarosław Jasiewicz]

Rich Shepard pisze:
> On Wed, 3 Mar 2010, Jaros?aw Jasiewicz wrote:
>
>> There are at least however on problem:
>> r.fuzzy for GRASS exist and not exist (by Francois Delclaux). I tried 
>> to contact with author but it failed and  module is not available 
>> from add-on web page. For now I leave name r.fuzzy, but if it could 
>> be the problem I can change name or remove both module.
>
> Jarek,
>
>   I've been in contact with Francois after downloading the most recent
> version (2000) of the code. At my request he sent me a thesis written 
> by his
> student who did most of the work. It's all in French, and my ability to
> read, write, and speak that language has deteriorated over the decades to
> the point that it's virtually useless. I'll be happy to share what I 
> have.
Nice, If you can
>
>> - for r.fuzzy shape parameter use nonstandard solution which is not 
>> applied in any software known for me. What you think about it? Or 
>> shall I change it into standard dilatation/concentration parameter 
>> (power/sqrt)
>
>   Hedges come in a range of degrees of strength. 'Slightly' is a 
> different
> hedge from 'very', for example.
This is not hedge, it is value which I replace 2 in formula sin^2 *x for 
standard sigmoid boundary. If parameter  is 0 the exponent is 2 on the 
other hand it changes the exponent to create more dilatation or more 
concentrate boundaries. It is non-standard solution but is described in 
description
>
>> - i plan to add custom fuzzy set definition but it require manual 
>> typing of sets of points or some more complex membership function 
>> definition which may be difficult without visual assistance, so I'd 
>> like to know if it would be really useful
>
>   In my opinion, what is needed first is a comprehensive description 
> of what
> such a set of modules is intended to do.
"Fuzzy set in geology" of Demico, Klir (2004) could be good starting 
point. I rather do not want to add fuzzy logic tutorial in geosciences 
to GRASS or at least not now.
>
> That is, in what situations should
> it be used and what insights should come from the results. This 
> information
> then guides how it should work with raster and vector (lines, areas, 
> points)
> data.
No idea on fuzzy logic on vector. But R package "sets" could be good 
tool to work on vector attributes.
>
>   I see two immediate applications. First, for areas traditionally 
> delimited
> by crisp boundaries (e.g., soils, geology, wetlands) we should have a
> mechanism to define fuzzy boundaries. 
it is included
> Second, we should have a mechanism to
> query maps with terms such as 'near,' 'far,' 'large,' and 'steep.'
It will be included in third module which is much difficult to write 
because it require parser of  expressions. But I work on it. So if you 
have software of Francois, send me it.

thanks
Jarek

P.S still ban on my e-mails on your server.
>
> R