<div dir="ltr"><div dir="ltr"><div>Thanks for the suggestion Mike,</div><div><br></div><div></div><div></div><div>I just tried running <br></div><div> {<br> "type": "filters.sample",<br> "radius": 0.001<br> },</div><div>on a test cloud with
n = 6650 points. With a 0.001 m threshold CloudCompare removes 1782 as duplicates (ca. 27%), and makes no visible difference to the displayed cloud, so the points removed appear genuine. However, with the above parameters, this PDAL pipeline only removes 6 duplicates.<br></div><div><br></div><div>I wondered whether filters.sample perhaps only considers proximity in XY space? (this isn't currently specified in the <a href="https://pdal.io/stages/filters.sample.html">documentation</a>). Apologies if I have missed something simple, I'm still learning PDAL, but I like it.</div><div><div><div><br></div><div>Thanks,</div><div>Andy<br></div><div><br></div>
</div>
</div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, 13 May 2019 at 13:26, Michael Smith <<a href="mailto:michael.smith.erdc@gmail.com">michael.smith.erdc@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div lang="EN-US"><div class="gmail-m_-3754680664947939958WordSection1"><p class="MsoNormal">Andrew,<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">You can use filters.sample and just set a small radius.<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">Mike<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><span style="font-size:10.5pt;color:black">-- <u></u><u></u></span></p><div><p class="MsoNormal"><span style="font-size:10.5pt;color:black">Michael Smith<u></u><u></u></span></p></div><div><p class="MsoNormal"><span style="font-size:10.5pt;color:black">Remote Sensing/GIS Center<u></u><u></u></span></p></div><div><p class="MsoNormal"><span style="font-size:10.5pt;color:black">US Army Corps of Engineers</span><u></u><u></u></p></div><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><u></u> <u></u></p><div style="border-color:rgb(181,196,223) currentcolor currentcolor;border-style:solid none none;border-width:1pt medium medium;padding:3pt 0in 0in"><p class="MsoNormal"><b><span style="font-size:12pt;color:black">From: </span></b><span style="font-size:12pt;color:black">pdal <<a href="mailto:pdal-bounces@lists.osgeo.org" target="_blank">pdal-bounces@lists.osgeo.org</a>> on behalf of Andrew Cunliffe <<a href="mailto:andrewmcunliffe@gmail.com" target="_blank">andrewmcunliffe@gmail.com</a>><br><b>Date: </b>Monday, May 13, 2019 at 8:21 AM<br><b>To: </b>PDAL Mailing List <<a href="mailto:pdal@lists.osgeo.org" target="_blank">pdal@lists.osgeo.org</a>><br><b>Subject: </b>[pdal] filtering duplicate points<u></u><u></u></span></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><div><div><p class="MsoNormal">Dear all,<u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><div><p class="MsoNormal">I am hoping someone might be able to help me to use PDAL to filter for duplicate points in a point cloud. <u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><div><p class="MsoNormal">By duplicate, I mean points that are less than a threshold distance (e.g. 0.001 m) from other points in the cloud. I'm working with photogrammetrically-generated point clouds, in some cases ca. 20-30% of the points are 'duplicates' so removing these has some big benefits later in the pipeline.<u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><div><p class="MsoNormal">I'm looking for a filter that functions like '<a href="https://www.cloudcompare.org/doc/wiki/index.php?title=Remove_duplicate_points" target="_blank">Remove duplicate points</a>' in CloudCompare. I wasn't able to see anything suitable under the filters > cull documentation, unless<span class="gmail-m_-3754680664947939958gmail-s2"> filters.voxelcenternearestneighbor</span> would achieve this with cell set to 0.001?<u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><div><p class="MsoNormal">If anyone else thinks that a filter.duplicate function might be helpful, I'm happy to submit a feature request via Github.<u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><div><p class="MsoNormal">Thanks<u></u><u></u></p></div><div><p class="MsoNormal">Andy<u></u><u></u></p></div><div><p class="MsoNormal"><br>-- <u></u><u></u></p><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><p class="MsoNormal"><span style="font-size:7.5pt;color:rgb(153,153,153)">Dr Andrew Cunliffe<br><br>Research Fellow<br>School of Geography<br>University of Exeter</span><u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><p class="MsoNormal">_______________________________________________ pdal mailing list <a href="mailto:pdal@lists.osgeo.org" target="_blank">pdal@lists.osgeo.org</a> <a href="https://lists.osgeo.org/mailman/listinfo/pdal" target="_blank">https://lists.osgeo.org/mailman/listinfo/pdal</a><u></u><u></u></p></div></div>
</blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><font size="1"><span style="color:rgb(153,153,153)">Dr Andrew Cunliffe<br><br>Research Fellow in Dryland Carbon Dynamics</span><span style="color:rgb(153,153,153)"><br>School of Geography, College of Life and Environmental Science,<br></span><span style="color:rgb(153,153,153)"><span style="color:rgb(153,153,153)">University of Exeter</span></span><span style="color:rgb(153,153,153)"><span><span style="color:rgb(153,153,153)"><br><br></span></span></span></font></div><div><font size="1"><span style="color:rgb(153,153,153)"><span><span style="color:rgb(153,153,153)"><a href="http://geography.exeter.ac.uk/staff/index.php?web_id=Andy_cunliffe" target="_blank">UoEx Profile</a><br></span></span></span></font></div><div><font size="1"><span style="color:rgb(153,153,153)"><a href="https://scholar.google.co.uk/citations?user=GEfm3PIAAAAJ&hl=en" target="_blank">Google Scholar</a><br></span></font></div><div><span style="color:rgb(153,153,153)"><br></span></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>