<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 21 Mar 2019, at 06:43, Nyall Dawson <<a href="mailto:nyall.dawson@gmail.com" class="">nyall.dawson@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">On Thu, 21 Mar 2019 at 15:59, Raymond Nijssen <<a href="mailto:r.nijssen@terglobo.nl" class="">r.nijssen@terglobo.nl</a>> wrote:<br class=""><blockquote type="cite" class=""><br class=""><br class=""><blockquote type="cite" class=""> def toLines(geom):<br class=""> return QgsGeometry(geom.get().boundary())<br class=""><br class="">(Using <a href="https://qgis.org/pyqgis/master/core/QgsAbstractGeometry.html#qgis.core.QgsAbstractGeometry.boundary" class="">https://qgis.org/pyqgis/master/core/QgsAbstractGeometry.html#qgis.core.QgsAbstractGeometry.boundary</a><br class="">)<br class=""><br class="">Nyall<br class=""></blockquote><br class="">Thanks Nyall, that works!<br class=""></blockquote><br class="">Great, thanks for the confirmation. And because I've got to do mapping<br class="">all day, I'm in a good mood, and you get a free PyQGIS lesson:<br class=""><br class="">geom.get() : gives you the underlying fundamental geometry object<br class="">attached to the feature. QgsFeature.geometry() returns a QgsGeometry<br class="">object, which is more or less a "container" for geometries. It's got<br class="">some convenient methods which apply to ALL geometry types, but<br class="">sometimes you need to dig down to the actual geometry primitive. In<br class="">that case you use geometry.get(), and you get the fundamental<br class="">QgsPoint/QgsLineString/QgsPolygon/etc object. It's actually generally<br class="">preferable to call "geometry.constGet()", IF you are doing some<br class="">operation which doesn't alter the geometry in place (like you are<br class="">here). But that's a complex microoptimisation.<br class=""><br class="">geom.get().boundary() gives you the topological boundary of the<br class="">primitive. For polygons this is their exterior + interior rings, for<br class="">lines it's their start and end point (unless it's a closed ring, in<br class="">which case you get a null geometry). Points have no boundary. Using<br class="">boundary() to convert polygons to lines is the most efficient method -<br class="">it's very heavily optimised, and works perfectly with curved geometry<br class="">types and maintains any Z or M values which may be present.<br class=""><br class="">Lastly, you need to wrap the result back up into a QgsGeometry object<br class="">- hence QgsGeometry(....boundary() ). This is because most of QGIS API<br class="">works with QgsGeometry objects (remember, they are like "containers"<br class="">holding a geometry), and NOT the fundamental geometry objects.<br class=""><br class="">Done! A super-efficient, rock solid approach which will work with all<br class="">input geometry types. Win!<br class=""><br class="">(for reference - this is what the polygons to lines algorithm actually<br class="">does in the background too)<br class=""></div></div></blockquote><div><br class=""></div><div>Thanks for the lesson for those of us watching from the sidelines too!</div><div><br class=""></div><div>Regards</div><div><br class=""></div><div>Tim</div><br class=""><blockquote type="cite" class=""><div class=""><div class=""><br class="">Nyall<br class=""><br class=""><br class=""><br class=""><br class=""><blockquote type="cite" class=""><br class=""><blockquote type="cite" class=""><br class=""><br class=""><blockquote type="cite" class=""><br class="">I will try tomorrow.<br class=""><br class="">One last question, it seems to me like the old code is working again in<br class="">3.7. Can you confirm that?<br class=""></blockquote><br class="">Shouldn't be -- maybe you have a leftover .py file here?<br class=""></blockquote><br class="">Indeed. I did a clean install and it is not working in my 3.7 anymore.<br class=""><br class=""><br class="">Regards,<br class="">Raymond<br class=""></blockquote>_______________________________________________<br class="">QGIS-Developer mailing list<br class=""><a href="mailto:QGIS-Developer@lists.osgeo.org" class="">QGIS-Developer@lists.osgeo.org</a><br class="">List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer<br class="">Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer</div></div></blockquote></div><br class=""><div class="">
<div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-ligatures: normal; font-variant-position: normal; font-variant-caps: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; font-weight: normal; letter-spacing: normal; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; line-height: normal; text-align: center;" class=""><span>—</span></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-ligatures: normal; font-variant-position: normal; font-variant-caps: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; letter-spacing: normal; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; line-height: normal; text-align: center;" class=""><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0); min-height: 14px;" class=""><br class=""></div><br class="Apple-interchange-newline" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"><span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"><span><span><span><span><span><span><span><span><span><span><img apple-inline="yes" id="2CB5D706-ED7C-4E08-A0AB-853EE5DB06AA" src="cid:1A5DF6DE-E302-4C28-BFBD-29663CBF1351" class=""></span><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0); min-height: 14px;" class=""><br class="Apple-interchange-newline"><br class="Apple-interchange-newline"><br class="Apple-interchange-newline"><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0); min-height: 14px;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class=""><b class="">Tim Sutton</b></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0); min-height: 14px;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class=""><b class="">Co-founder:</b><span class="Apple-converted-space"> </span>Kartoza</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class=""><b class="">Ex Project chair:</b><span style="font-weight: normal;" class=""><span class="Apple-converted-space"> </span><a href="http://QGIS.org" class="">QGIS.org</a></span></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0); min-height: 14px;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class="">Visit <a href="http://kartoza.com/" class=""><span style="-webkit-text-stroke-color: rgb(71, 135, 255);" class="">http://kartoza.com</span></a> to find out about open source:</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0); min-height: 14px;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class="">Desktop GIS programming services</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class="">Geospatial web development</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class="">GIS Training</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class="">Consulting Services</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0); min-height: 14px;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class=""><b class="">Skype</b>: timlinux </div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: center; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: initial; text-decoration: none; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; margin: 0px; line-height: normal; -webkit-text-stroke-color: rgb(0, 0, 0);" class=""><b class="">IRC:</b><span class="Apple-converted-space"> </span>timlinux on #qgis at <a href="http://freenode.net" class="">freenode.net</a></div>
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