<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">Thanks!<br><br><div dir="ltr">Nicolas Cadieux<div><a href="https://gitlab.com/njacadieux">https://gitlab.com/njacadieux</a></div></div><div dir="ltr"><br><blockquote type="cite">Le 10 janv. 2023 à 23:37, Terry Morse via QGIS-User <qgis-user@lists.osgeo.org> a écrit :<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div style="color:rgb(0, 0, 0);font-family:arial,sans-serif;font-size:12pt"><p style="margin: 0.1rem 0; line-height: 1.0;"><em>Principles of Geographical Information Systems</em>, by Burrough and McDonnell (Oxford: Oxford Univ. Pr., 1998; ISBN 0198233655) has a brief treatment of point-in-polygon on page 64 (box 3.4), or see <em>Principles of Geographical Information Systems</em>, 3rd ed., by Burrow, McDonnell, and Lloyd (Oxford: Oxford Univ. Pr. 2015; ISBN 0198742845), where it is Box 7.3 on page 140. It may not be as detailed as you want, but it's a beginning. Wikipedia has an article with a little more detail at <a href="https://en.wikipedia.org/wiki/Point_in_polygon">https://en.wikipedia.org/wiki/Point_in_polygon</a> that includes references.</p>
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<p style="margin: 0.1rem 0; line-height: 1.0;">There are scripts at <a href="https://www.geeksforgeeks.org/how-to-check-if-a-given-point-lies-inside-a-polygon/">https://www.geeksforgeeks.org/how-to-check-if-a-given-point-lies-inside-a-polygon/</a> in both c++ and python.</p>
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<p style="margin: 0.1rem 0; line-height: 1.0;">Terry Morse</p>
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<p style="margin: 0.1rem 0; line-height: 1.0;"><a href="mailto:tmorse@teleport.com">tmorse@teleport.com</a></p>
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<p>-----Original Message-----<br>From: Nicolas Cadieux <njacadieux.gitlab@gmail.com><br>Sent: Jan 10, 2023 7:23 PM<br>To: Qgis List <qgis-user@lists.osgeo.org><br>Subject: [Qgis-user] The theory behind topology</p>
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Hi,
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<div>I am curious to learn the math behind topology. For example, I would like to know how something like “selecting points in a polygon “ is actually done from a programming point of view. If you have a good resource (books, video, articles…) please send it my way.</div>
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<div>Thanks<br><br>
<div dir="ltr">Nicolas Cadieux
<div><a href="https://gitlab.com/njacadieux">https://gitlab.com/njacadieux</a></div>
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