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<p>Hi all,</p>
<p>I have a set of projected spatial points (id, x, y, dist, value) that needs to be filtered. For each point I have to find the other ones falling within a variable distance. For each selection, I need only the one with the maximum value or, if duplicated,
keeping just one.</p>
<p>I tried to check the available tools and I found out what follows:<o:p></o:p></p>
<p style="margin-left:36.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>A simpler possibility would be to use the “Select by expression”, but I’m not that familiar with the syntax and I ended up with [clearly non-working]: CASE WHEN distance($currentfeature)<”dist” THEN max(“value”) END</p>
<p style="margin-left:36.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Another possibility would be to improve the following R code, available online (thanks to the author)</p>
<p>Any (R, Python, else) suggestion?</p>
<pre><span class="com"><o:p> </o:p></span></pre>
<pre><span class="com"><o:p> </o:p></span></pre>
<pre><span class="com">##Layer=vector</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="com">##ID=Field Layer</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="com">##distance= Field Layer</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="com">##Output= output vector</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">library</span><span class="pun">(</span><span class="pln">rgeos</span><span class="pun">)</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">library</span><span class="pun">(</span><span class="pln">sp</span><span class="pun">)</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">library</span><span class="pun">(</span><span class="pln">spdep</span><span class="pun">)</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln"><o:p> </o:p></span></pre>
<pre><span class="pln">coordi </span><span class="pun"><-</span><span class="pln"> </span><span class="kwd">as</span><span class="pun">.</span><span class="pln">matrix</span><span class="pun">(</span><span class="pln">coordinates</span><span class="pun">(</span><span class="typ">Layer</span><span class="pun">))</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">tram_nb </span><span class="pun"><-</span><span class="pln"> dnearneigh</span><span class="pun">(</span><span class="pln">coordi</span><span class="pun">,</span><span class="pln"> d1 </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">,</span><span class="pln"> d2 </span><span class="pun">=</span><span class="pln"> distance</span><span class="pun">,</span><span class="pln">row</span><span class="pun">.</span><span class="pln">names</span><span class="pun">=</span><span class="typ">Layer</span><span class="pun">[[</span><span class="pln">ID</span><span class="pun">]])</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">tram_nb</span><span class="pun"><-</span><span class="kwd">as</span><span class="pun">.</span><span class="pln">data</span><span class="pun">.</span><span class="pln">frame</span><span class="pun">(</span><span class="pln">card</span><span class="pun">(</span><span class="pln">tram_nb</span><span class="pun">))</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">tram</span><span class="pun"><-</span><span class="pln">cbind</span><span class="pun">(</span><span class="kwd">as</span><span class="pun">.</span><span class="pln">vector</span><span class="pun">(</span><span class="typ">Layer</span><span class="pun">[[</span><span class="pln">ID</span><span class="pun">]]),</span><span class="pln"> tram_nb</span><span class="pun">)</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="typ">Coord</span><span class="pun"><-</span><span class="pln">cbind</span><span class="pun">()</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">n</span><span class="pun"><-</span><span class="pln">length</span><span class="pun">(</span><span class="typ">Layer</span><span class="pun">[[</span><span class="pln">ID</span><span class="pun">]])</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="kwd">for</span><span class="pun">(</span><span class="pln">i </span><span class="kwd">in</span><span class="pln"> </span><span class="lit">1</span><span class="pun">:</span><span class="pln">n</span><span class="pun">){</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln"> </span><span class="kwd">if</span><span class="pln"> </span><span class="pun">(</span><span class="pln">tram</span><span class="pun">[</span><span class="pln">i</span><span class="pun">,</span><span class="lit">2</span><span class="pun">]!=</span><span class="lit">0</span><span class="pln"> </span><span class="pun">){</span><span class="pln"> </span><span class="typ">Coord</span><span class="pln"> </span><span class="pun"><-</span><span class="pln">rbind</span><span class="pun">(</span><span class="typ">Coord</span><span class="pun">,</span><span class="pln">cbind</span><span class="pun">(</span><span class="pln">coordi</span><span class="pun">[</span><span class="pln">i</span><span class="pun">,</span><span class="lit">1</span><span class="pun">],</span><span class="pln"> coordi</span><span class="pun">[</span><span class="pln">i</span><span class="pun">,</span><span class="lit">2</span><span class="pun">],</span><span class="kwd">as</span><span class="pun">.</span><span class="pln">vector</span><span class="pun">(</span><span class="typ">Layer</span><span class="pun">[[</span><span class="pln">ID</span><span class="pun">]])[</span><span class="pln">i</span><span class="pun">]))</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pun">}</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pun">}</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">x</span><span class="pun"><-</span><span class="kwd">as</span><span class="pun">.</span><span class="pln">numeric</span><span class="pun">(</span><span class="typ">Coord</span><span class="pun">[,</span><span class="lit">1</span><span class="pun">])</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">y</span><span class="pun"><-</span><span class="kwd">as</span><span class="pun">.</span><span class="pln">numeric</span><span class="pun">(</span><span class="typ">Coord</span><span class="pun">[,</span><span class="lit">2</span><span class="pun">])</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">X</span><span class="pun"><-</span><span class="pln">cbind</span><span class="pun">(</span><span class="pln">x</span><span class="pun">,</span><span class="pln">y</span><span class="pun">)</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">matrix</span><span class="pun"><-</span><span class="kwd">as</span><span class="pun">.</span><span class="pln">matrix</span><span class="pun">(</span><span class="pln">X</span><span class="pun">)</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="pln">matrix</span><span class="pun"><-</span><span class="typ">SpatialPointsDataFrame</span><span class="pun">(</span><span class="pln">matrix</span><span class="pun">,</span><span class="kwd">as</span><span class="pun">.</span><span class="pln">data</span><span class="pun">.</span><span class="pln">frame</span><span class="pun">(</span><span class="typ">Coord</span><span class="pun">),</span><span class="pln">proj4string</span><span class="pun">=</span><span class="pln">CRS</span><span class="pun">(</span><span class="typ">Layer</span><span class="pun">))</span><span class="pln"><o:p></o:p></span></pre>
<pre><span class="typ">Output</span><span class="pun">=</span><span class="pln">matrix</span></pre>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you in advance for your help!</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">All the best,</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Nic</p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif"><o:p> </o:p></span></p>
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