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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>If you are talking about adding an additional column to the table, I see no reason why you shouldn’t be able to, just as you can have say multiple geometry or a geometry and geography column in same table.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> or are you talking about adding an additional attribute to the pcpatch column? Such a change would be a bit more involved.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> Neil Underhill [mailto:neil.underhill@gmail.com] <br><b>Sent:</b> Wednesday, June 28, 2023 4:35 AM<br><b>To:</b> Regina Obe <lr@pcorp.us><br><b>Cc:</b> pgpointcloud@lists.osgeo.org<br><b>Subject:</b> Re: [pgpointcloud] How to create a PcPoint table in PostGIS?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal>Hello all,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>A follow on question to the below... is it possible to add an additional column to data stored as a pgPointcloud ?<o:p></o:p></p></div><div><p class=MsoNormal>Reason I ask is that I am using the RANSAC algorithm to detect roof shapes (i.e. which Cartesian equation of a plane fits the most points). <o:p></o:p></p></div><div><p class=MsoNormal>Currently the algorithm will only find the plane equation which fits the biggest number of points in a point cloud. However there is usually more than one roof in a point cloud, so I would like to add a column to indicate that a point already belongs to a plane so the algorithm can exclude, re-reun and find the next biggest biggest plane, etc. etc., until a minimum threshold in area is reached. <o:p></o:p></p></div><div><p class=MsoNormal>I am thinking the new column should be either a binary flag, or a foreign key to a separate table of plane equations. <o:p></o:p></p></div><div><p class=MsoNormal>If the above is not possible, then I would assume that I need to dump out the pgPointcloud into a standard PostGIS point geometry table, where I can add additional column? <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Thanks,<br>Neil<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Tue, 28 Mar 2023 at 21:08, Regina Obe <<a href="mailto:lr@pcorp.us">lr@pcorp.us</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>You can use the PC_Explode function to access individual points. It converts a patch into individual PcPoints.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><a href="https://pgpointcloud.github.io/pointcloud/functions/patchs.html#pc-explode" target="_blank">https://pgpointcloud.github.io/pointcloud/functions/patchs.html#pc-explode</a></span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>You can use the PC_PointN to access individual points by index number in the patch.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><a href="https://pgpointcloud.github.io/pointcloud/functions/patchs.html#pc-pointn" target="_blank">https://pgpointcloud.github.io/pointcloud/functions/patchs.html#pc-pointn</a></span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>So for example to pick at random 3 points, you can do something like (NOT TESTED)</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>SELECT PC_PointN(pa, index) AS pcp</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>FROM patches AS p, PC_NumPoints(<a href="http://p.pa" target="_blank">p.pa</a>) AS np</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>CROSS JOIN LATERAL (SELECT index FROM generate_series(1, np) AS index ORDER BY random() LIMIT 3) AS pi(index);</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Hope that helps,</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Regina</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> </span><o:p></o:p></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> pgpointcloud [mailto:<a href="mailto:pgpointcloud-bounces@lists.osgeo.org" target="_blank">pgpointcloud-bounces@lists.osgeo.org</a>] <b>On Behalf Of </b>Neil Underhill<br><b>Sent:</b> Tuesday, March 28, 2023 12:47 PM<br><b>To:</b> <a href="mailto:pgpointcloud@lists.osgeo.org" target="_blank">pgpointcloud@lists.osgeo.org</a><br><b>Subject:</b> [pgpointcloud] How to create a PcPoint table in PostGIS?</span><o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>I have a .laz file with about 51m points in it (225 MB in size), and want to run a RANSAC algorithm to detect roof planes. <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>I would like to add the LIDAR data to a PostGIS database so I can interact with other geospatial layers (e.g. use a mask to filter the points to consider) and also access individual points to input into the algorithm. <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>I have been following the information here (<a href="https://pgpointcloud.github.io/pointcloud/concepts/objects.html" target="_blank">https://pgpointcloud.github.io/pointcloud/concepts/objects.html</a>) about the different Point Cloud Objects. <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>My question is, if I store the data as a PcPatch, will I be able to access the individual points (e.g. select three points at random, that may or may not be in the same patch) ? <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>If not, it seems I will need to store as PcPoint. If it's the latter, I am not clear how I create a database with PcPoint objects, as the example in the Quickstart (<a href="https://pgpointcloud.github.io/pointcloud/quickstart.html" target="_blank">https://pgpointcloud.github.io/pointcloud/quickstart.html</a>) only creastes a PcPatch table. <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Thanks for any advice,<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Neil<o:p></o:p></p></div></div></div></div></div></div></blockquote></div></div></div></div></div></body></html>