<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Hi,</div><div><br></div><div>I am not at what needs to be analyzed in this case but yes, canonical analysis needs to be well understood before being used. </div><div><br></div><div>You can go to Pierre Legendre and Louis Legendre, Numerical Ecology, for help. P Legendre also has a book on Spatial analysis in R that can be found.</div><div><br></div><div>Cheers</div><div>Nicolas</div><div><br></div><div>P.S.</div><div><br></div><div>As far as statistical software, R is unbeatable for cutting edge sciences. It is scary because it's a statistical language before being a statistical software. But I agree, some statistics are implement in GIS software without any thought.</div><div><br>Le 23 juin 2017 à 15:11, Falk Huettmann <<a href="mailto:fhuettmann@alaska.edu">fhuettmann@alaska.edu</a>> a écrit :<br><br></div><blockquote type="cite"><div><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><div dir="ltr">Hi there,<div><br></div><div>in my view and if I may comment here:</div><div>while R is scary (as stated below), so are probably many of the wrapped R packages really,</div><div>PCAs are even more scary, and their underlying mindsets,</div><div>and the real horror starts when such things get</div><div>implemented into 'homebrews' and such tools, or</div><div>into QGIS and just as point and klick.</div><div><br></div><div>As a rule, I would highly suggest to stay clear of such efforts and concepts.</div><div>It's no good science, and not much defendable. Unless well thought out,</div><div>it harms the product and reputation you want to create.</div><div>(for a bad example see Krigging in some major commercial GIS...</div><div> We have seen such things many places).</div><div><br></div><div>There should first be a good debate about statistics, if pursued as tools in QGIS etc.</div><div>Arguably, unless it's predictive (for inference etc) it has no much value these days anymore.</div><div><br></div><div>Agreed,</div><div>it's a tragedy of our time that such old things still happen, all the time,</div><div>and in the sciences. </div><div>But it ain't no good, really, and is no good progress. My word for it.</div><div><br></div><div>(I also agree that it is good to keep avenues open for such</div><div>work, as an option and for people who know what they are doing and why; sure. </div><div>But not more than that. Many bad examples exist all over for decades)</div><div><br></div><div>Feel free to follow up as needed; kind regards</div><div> Falk Huettmann</div><div> Uni of Alaska Fairbanks</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Jun 23, 2017 at 10:57 AM, Nicolas Cadieux <span dir="ltr"><<a href="mailto:nicolas.cadieux@archeotec.ca" target="_blank">nicolas.cadieux@archeotec.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div></div><div>Hi, </div><div>You can use R for PCA.</div><div>Use the R Commander package to add a GUI. R can be scary at first.</div><div>Nicolas</div><div><br>Le 23 juin 2017 à 11:03, image [via <a href="http://OSGeo.org" rel="nofollow" link="external" target="_blank">OSGeo.org</a>] <<a href="http:///user/SendEmail.jtp?type=node&node=5325361&i=0" rel="nofollow" link="external" target="_blank">[hidden email]</a>> a écrit :<br><br></div><blockquote style="border-left:2px solid #cccccc;padding:0 1em" type="cite"><div>Good afternoon,
<br><br>i'm working on windows with several opensource tools (qgis, otb, grass...),
<br><br>I generated several OTB texture indices. Now, i want to evaluate the information 's redundancy thanks to a Principal Component Analysis.
<br><br>=> Is it possible to do that with some opensource tools (otb? qgis? grass?) Moreover, I would like set a mask AND set a spectral subset (in order to ignore some indices bands which seems "strange" and not relevant to introduce into the process).
<br><br>Could you throw light for me?
<br><br>In advance, thank you very much for your help.
<br><br>Kind regards.
<br>
<br>
<hr noshade="" size="1" color="#cccccc">
<div style="color:#444;font:12px tahoma,geneva,helvetica,arial,sans-serif">
<div style="font-weight:bold">If you reply to this email, your message will be added to the discussion below:</div>
<a href="http://osgeo-org.1560.x6.nabble.com/Principal-Component-Analysis-tp5325338.html" rel="nofollow" link="external" target="_blank">http://osgeo-org.1560.x6.<wbr>nabble.com/Principal-<wbr>Component-Analysis-tp5325338.<wbr>html</a>
</div>
<div style="color:#666;font:11px tahoma,geneva,helvetica,arial,sans-serif;margin-top:.4em;line-height:1.5em">
To start a new topic under QGIS - User, email <a href="http:///user/SendEmail.jtp?type=node&node=5325361&i=1" rel="nofollow" link="external" target="_blank">[hidden email]</a> <br>
To unsubscribe from QGIS - User, <a rel="nofollow" link="external">click here</a>.<br>
<a href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml" rel="nofollow" style="font:9px serif" link="external" target="_blank">NAML</a>
</div></div></blockquote>
<br><hr align="left" width="300">
View this message in context: <a href="http://osgeo-org.1560.x6.nabble.com/Principal-Component-Analysis-tp5325338p5325361.html" target="_blank">Re: Principal Component Analysis ?</a><br>
Sent from the <a href="http://osgeo-org.1560.x6.nabble.com/QGIS-User-f4125267.html" target="_blank">QGIS - User mailing list archive</a> at <a href="http://Nabble.com">Nabble.com</a>.<br><br>______________________________<wbr>_________________<br>
Qgis-user mailing list<br>
<a href="mailto:Qgis-user@lists.osgeo.org">Qgis-user@lists.osgeo.org</a><br>
List info: <a href="https://lists.osgeo.org/mailman/listinfo/qgis-user" rel="noreferrer" target="_blank">https://lists.osgeo.org/<wbr>mailman/listinfo/qgis-user</a><br>
Unsubscribe: <a href="https://lists.osgeo.org/mailman/listinfo/qgis-user" rel="noreferrer" target="_blank">https://lists.osgeo.org/<wbr>mailman/listinfo/qgis-user</a><br></blockquote></div><br></div>
</div></blockquote></body></html>