<html><head></head><body><div class="ydp4c28490eyahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div dir="ltr" data-setdir="false">Hi Dave, </div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">You will probably want to convert your LIDAR point cloud to a DEM raster. You can do that easily in Q.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">It sounds like you may be looking for Topographic Prominence. You should look at the Wikipedia page for that to get a start. </div><div dir="ltr" data-setdir="false"><a href="https://en.wikipedia.org/wiki/Topographic_prominence#Calculations_and_mathematics" rel="nofollow" target="_blank">https://en.wikipedia.org/wiki/Topographic_prominence#Calculations_and_mathematics</a></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">There is an open source project called WinProm, you can see the code on Github and it looks like there are windows exe files too.</div><div dir="ltr" data-setdir="false"><a href="https://github.com/edwardearl/winprom" rel="nofollow" target="_blank">https://github.com/edwardearl/winprom</a><br></div><div><br></div><div dir="ltr" data-setdir="false">You can also use the r.geomorphon tool in GRASS and then extract summits and depressions. GRASS can be run from within QGIS.</div><div dir="ltr" data-setdir="false"><a href="https://grass.osgeo.org/grass78/manuals/r.geomorphon.html" rel="nofollow" target="_blank">https://grass.osgeo.org/grass78/manuals/r.geomorphon.html</a><br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">There is likely a way to do it in python or R also, using one of the math or science packages, to find peaks and valleys in a 2d surface (Calculus). This is a well developed area of research, for example in biomedicine.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">----------------------------------------------------------------------<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Message: 1<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Date: Thu, 2 Apr 2020 19:51:18 +0000<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">From: Dave Marshall <<a href="mailto:43carnaby@gmail.com" style="color: rgb(25, 106, 212); text-decoration-line: underline;" rel="nofollow" target="_blank">43carnaby@gmail.com</a>><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">To: <a href="mailto:qgis-user@lists.osgeo.org" style="color: rgb(25, 106, 212); text-decoration-line: underline;" rel="nofollow" target="_blank">qgis-user@lists.osgeo.org</a><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Subject: [Qgis-user] Working with LIDAR data in QGIS<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Message-ID:<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"> <CAOuYquPg8Yjj95g4yGmpKEVg06q53B-u=<a href="mailto:sO58MJBoNLR1R92sQ@mail.gmail.com" style="color: rgb(25, 106, 212); text-decoration-line: underline;" rel="nofollow" target="_blank">sO58MJBoNLR1R92sQ@mail.gmail.com</a>><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Content-Type: text/plain; charset="utf-8"<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Hello,<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">I am relatively new to QGIS but have been able to generate some useful<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">images of LIDAR data with contours and shading. My need is to be able to<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">identify hill summits and preferably cols as well and to extract the<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">precise location and height of these positions. I'd like to know if it's<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">possible to extract the height data for a specific point using QGIS.<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Thanks in advance for any help with this,<br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Dave Marshall</div></div><br></div></div></body></html>