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<div class="moz-cite-prefix">On 06/06/2024 3:09, Janet Choate via
grass-user wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAEqw1VzTdprBBQoO=ywbJog910j2mvkO75npu4yAFRifn2DToA@mail.gmail.com">
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<div dir="ltr">Hi GRASS community,
<div>I downloaded land cover data from NLCD and reclassed values
into 6 categories to generate a vegetation/landcover type
raster (tree, shrub, grass, non-veg, water, developed) that is
composed of IDs (i.e. 11=tree, 5-shrub, etc...) </div>
<div>I also have a 90 meter patch raster.</div>
<div>Any given 90 meter patch may have more than one vegetation
type ID occurring in it.</div>
<div>I would like to generate percent coverage maps to find the
percent that each vegetation type occupies of each patch (i.e.
patch 1 is composed of 60% tree, 30% shrub, 10%grass).</div>
</div>
</blockquote>
<p><br>
</p>
<p>If a vector approach is relevant, you could:</p>
<p>(Like Anna's suggestion, requires some additional work...)<br>
</p>
<p>1- convert both rasters to vector</p>
<p>2- calculate in advance the area of each patch</p>
<p>3- run `v.overlay` with the patch vector as ainput, and the
landcover as binput.</p>
<p>4- The output vector will have all landcover polygons cut at the
patch boundaries. It will retain any attributes from the patches,
for identifying which patch each new landcover is in. And it will
have the new area of each of these cut landcover polygons. So
dividing each new (cut) landcover area by the original a_Area
value will give you the percent coverage. <br>
</p>
<p><br>
</p>
<p><br>
</p>
<blockquote type="cite"
cite="mid:CAEqw1VzTdprBBQoO=ywbJog910j2mvkO75npu4yAFRifn2DToA@mail.gmail.com">
<div dir="ltr">
<div>Is it possible to compute percent cover from a vegetation
type ID map?</div>
<div>Any advice would be much appreciated, I have unsuccessfully
tried to do this in GRASS as well as R.</div>
<div>thank you,</div>
<div>Janet</div>
<div>
<div><br>
</div>
<span class="gmail_signature_prefix">-- </span><br>
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data-smartmail="gmail_signature">
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<div>
<div dir="ltr">Tague Team Lab Manager</div>
<div>1005 Bren Hall</div>
<div>UCSB, Santa Barbara, CA.</div>
</div>
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<br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
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</blockquote>
<pre class="moz-signature" cols="72">--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918</pre>
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