<div dir="ltr">Hi Antonio<div>Thanks for your reply. Very interesting despite my lack of Italian and I can see some application for your research. </div><div>However, it's not quite what I meant - what I want to try to do is work out which part of a defined site (I have a polygon) is least (or most) visible from the surrounding landscape within a defined radius (I have raster of elevation data). Any ideas?</div>
<div>Many thanks</div><div>Angus</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On 24 September 2013 11:19, Antonio Falciano <span dir="ltr"><<a href="mailto:afalciano@yahoo.it" target="_blank">afalciano@yahoo.it</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Il 24/09/2013 11:48, Angus Jeffery ha scritto:<br>
<div><div class="h5">> Hello<br>
> I am doing some visibility analysis work in gvSIG. I often use the grass<br>
> r.cva process and various of the sextante visibility tools for standard<br>
> viewsheds. I would like to work out how to do a 'reverse viewshed',<br>
> whereby the output is a raster/heat map within a parcel of land, showing<br>
> which areas are more or less visible from the surrounding area outside<br>
> the parcel of land in the wider landscape. Does anyone have any ideas<br>
> which tools to use and how to approach this most efficiently in gvSIG?<br>
> Best regards<br>
> Angus<br>
<br>
</div></div>Hi Angus,<br>
"more or less visible" suggests me you are trying to compute the so<br>
called "fuzzy viewshed", i. e. the degree of visibility between 0 and 1<br>
of targets and vice versa. This kind of viewsheds are more sofisticated<br>
than binary ones, which only say if a target is visible or not. The<br>
logic consists into applying a fuzzy membership based on some physic law<br>
to visibility and finally multiply the resulting raster with the<br>
classical binary viewshed.<br>
Some years ago [1] I reproduced them with SEXTANTE models (if I remember<br>
well with SEXTANTE 0.6), but I'm not sure if all the tools involved in<br>
this model are quite stable to do this work at the moment. Good luck!<br>
<br>
Cheers,<br>
Antonio<br>
<br>
[1] <a href="http://slidesha.re/aaTMsa" target="_blank">http://slidesha.re/aaTMsa</a> (in Italian, sorry!)<br>
<span class="HOEnZb"><font color="#888888"><br>
--<br>
Antonio Falciano<br>
<a href="http://www.linkedin.com/in/antoniofalciano" target="_blank">http://www.linkedin.com/in/antoniofalciano</a><br>
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