[GRASS-user] Re: count pixels by attribute in sampling units

[Patrick Giraudoux]

>> 2/ Regarding r.le*, it would be nice to get simple and quick reports
>> on sampling unit composition (e.g. number of pixels of each attribute
>>     
>> category, mean, min, max, etc. e.g. the same as for r.neighbors)
>> without going straight to time-consuming shape analysis. Indeed, 
>> classical neighborhood analysis is limited to 25 pixels in GRASS and
>> there are many cases where statistics on larger sampling units are
>> needed. It may be that such simple statistics on sampling units can
>> be obtained with other GRASS functions, but I cannot find one
>> throughout books and threads on the web... and no feed back yet on
>> this on the GRASS list.
>>     
>
> it is an easy edit of the r.neighbors source code if you want to make
> that number more than 25.
>
> but yes, there are modules to do this.
> r.buffer + r.univar,
> v.buffer + v.rast.stats
> v.what.rast
> .... more?
>   
Yes indeed,  taking it as a training,  I am managing with UNIX stripts 
to create buffers of the relevant sizae centered on sites and automate 
data extraction with those functions.
> It might be nice for that to be built into r.le.* automatically, and
> probably not that hard to do, but generally I would prefer if new
> development went into r.li, and r.le only got bug fixes. I don't mind
> simple niceties being added but it seems like wasted effort when r.li
> is supposed to replace r.le. Of course it is open source so if someone
> prefers to keep adding to r.le I'm not going to stop them or refuse
> patches.
>   
By the way, I did NOT have a feed back with this possible r.li.setup 
'bug'. See following copy :

> -------- Message original --------
> Sujet: 	r.li.setup trouble with circle
> Date: 	Mon, 24 Dec 2007 10:12:24 +0100
> De: 	Patrick Giraudoux <patrick.giraudoux at univ-fcomte.fr>
> Répondre à :: 	patrick.giraudoux at univ-fcomte.fr
> Organisation: 	Université de Franche-Comté
> Pour :: 	grass-user at lists.osgeo.org
>
>
>
> Dear listers,
>
> I am working with grass 63 cvs (grass-6.3.cvs_src_snapshot_2007_12_22 ) 
> and exploring r.li programme possibilities but fails to get to the end 
> of the r.li.setup process in 'sampling area settings'.
>
> When I twitch 'Sample units' and try to setup the size of circle 
> sampling units centered over site (Rectangle works fine), I get the 
> message 'Type integer values or set raster map name', and this for any 
> integer value (100, 500, etc.) entered.
>
> Any hint welcome...
>
> Patrick


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