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<div class="moz-cite-prefix">On 10/05/2013 01:17 AM, Gregory Penn
wrote:<br>
</div>
<blockquote
cite="mid:9AD70236-FFBF-4988-B41B-854E0C4C1BDE@gmail.com"
type="cite">
<pre wrap="">This question is directly related to my previous one, in which I described the overall visualization that I'm trying to achieve.
I've managed to create a display of my raster data that looks more or less like I want, i.e. masked with the appropriate vector and color mapped. It occurred to me that if I could create a raster with an alpha channel using the mask, such that the areas that are masked become null or no value pixels, then I might be able to use r.blend with that raster and my base map raster to get the effect that I'm trying for.
</pre>
</blockquote>
<br>
If I understand your goal, what you want to do is switch the order
of the operations a bit. Create your mask from the species range map
*before* you do the blend, and then make a new raster of the heat
map using r.mapcalc (i.e. r.mapcalc heat_masked = heat). Now
*remove* the mask. THis will leave you with a masked head map, and
the original basemap unmasked. <br>
And now do the r.blend. The masked out areas of the heat map will be
null, and not affect the basemap, and those areas inside the mask
will have the heat values, and thus get blended with the basemap.
Finally add your administrative vectors, and you're done.<br>
One point troubles me in your description of the problem. You want
"clean curves" at the boundary of the mask, even though the heat
raster has a large resolution. IIUC, this won't work. The only way
to achieve smooth curves is to resample the heat raster at a smaller
resolution. Or alternatively to convert it to a vector polygon
layer, using the "-s" flag for r.to.vect (smooth boundaries). <br>
<br>
<blockquote
cite="mid:9AD70236-FFBF-4988-B41B-854E0C4C1BDE@gmail.com"
type="cite">
<pre wrap="">
I also have no idea how the d.* and r.* modules deal with alpha channels and would welcome some direction to appropriate documentation.
Cheers,
Gregory
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<pre class="moz-signature" cols="72">--
Micha Silver
GIS Consultant, Arava Development Co.
<a class="moz-txt-link-freetext" href="http://www.surfaces.co.il">http://www.surfaces.co.il</a></pre>
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