<div dir="ltr">Hi<div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Jan 24, 2014 at 1:12 AM, A Huarte <span dir="ltr"><<a href="mailto:ahuarte47@yahoo.es" target="_blank">ahuarte47@yahoo.es</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif"><div>
<span>Hi!</span></div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif"><span><br></span></div>
<div style="font-style:normal;font-size:16px;background-color:transparent;font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif"><span>About simplification (no clustering), </span><span style="background-color:transparent;font-size:12pt">I think that the </span><span style="background-color:transparent">If we discard points based on the distance to the last fetched and rendered point (</span><span style="background-color:transparent"><a href="https://github.com/qgis/QGIS/blob/master/src/core/qgsfeatureiterator.cpp#L36" target="_blank">https://github.com/qgis/QGIS/blob/master/src/core/qgsfeatureiterator.cpp#L36</a>) it will be very effective to render big dense points layers. I have a GIS application using this technique and it draws LAS files (> 30mb) "fast".</span></div>
<div style="font-style:normal;font-size:16px;background-color:transparent;font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif"><span style="background-color:transparent"><br>
</span></div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif"><span style="background-color:transparent">I would like write a "point simplifier" in QGIS to validate results.</span></div>
<div style="font-style:normal;font-size:16px;background-color:transparent;font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif"><span style="background-color:transparent">Do you agree ?</span></div>
</div></div></blockquote><div><br></div><div>I think this would be great. Since you are doing a full scan of the dataset, you should be able to count how many points each aggregate point represents right? I was thinking we could pass that the the renderer as a 'virtual' attribute so that we can use it to e.g. scale the symbol size.</div>
<div><br></div><div>+1 from me to implement this anyway as a new cluster renderer (or a patch the point displacement renderer if that seems workable).</div><div><br></div><div>Regards</div><div><br></div><div>Tim</div><div>
</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif">
<div style="font-style:normal;font-size:16px;background-color:transparent;font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif"><span style="background-color:transparent"><br>
</span></div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif"><span style="background-color:transparent">Alvaro</span></div>
<div><br></div><blockquote style="border-left:2px solid rgb(16,16,255);margin-left:5px;margin-top:5px;padding-left:5px"> <div style="font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif;font-size:12pt">
<div style="font-family:HelveticaNeue,'Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif;font-size:12pt"> <div dir="ltr"> <hr size="1"> <font face="Arial"> <b><span style="font-weight:bold">De:</span></b> Tim Sutton <<a href="mailto:lists@linfiniti.com" target="_blank">lists@linfiniti.com</a>><br>
<b><span style="font-weight:bold">Para:</span></b> Martin Dobias <<a href="mailto:wonder.sk@gmail.com" target="_blank">wonder.sk@gmail.com</a>> <br><b><span style="font-weight:bold">CC:</span></b> qgis-developer <<a href="mailto:qgis-developer@lists.osgeo.org" target="_blank">qgis-developer@lists.osgeo.org</a>>; "<a href="mailto:tech@wildintellect.com" target="_blank">tech@wildintellect.com</a>" <<a href="mailto:tech@wildintellect.com" target="_blank">tech@wildintellect.com</a>> <br>
<b><span style="font-weight:bold">Enviado:</span></b> Jueves 23 de enero de 2014 23:16<div class="im"><br> <b><span style="font-weight:bold">Asunto:</span></b> Re: [Qgis-developer] On the fly simplication of point layers<br>
</div></font> </div> <div><br><div><div class="h5"><div><div><div dir="ltr">Hi<div><br clear="none"><br clear="none"><div>On Wed, Jan 22, 2014 at 2:47 PM, Tim Sutton <span dir="ltr"><<a rel="nofollow" shape="rect" href="mailto:lists@linfiniti.com" target="_blank">lists@linfiniti.com</a>></span> wrote:<br clear="none">
<blockquote style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi<div><br clear="none"><br clear="none"><div><div><div>On Wed, Jan 22, 2014 at 1:23 PM, Martin Dobias <span dir="ltr"><<a rel="nofollow" shape="rect" href="mailto:wonder.sk@gmail.com" target="_blank">wonder.sk@gmail.com</a>></span> wrote:<br clear="none">
<blockquote style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>On Wed, Jan 22, 2014 at 4:33 PM, Tim Sutton <<a rel="nofollow" shape="rect" href="mailto:lists@linfiniti.com" target="_blank">lists@linfiniti.com</a>> wrote:<br clear="none">
>><br clear="none">
>> Actually the point displacement renderer already does clustering,<br clear="none">
>> though it lacks more options to customize how the clustered symbol<br clear="none">
>> would look like.<br clear="none">
>><br clear="none">
><br clear="none">
> Doesnt it do the reverse? i.e. when more than one point falls in the same<br clear="none">
> place, it shifts them aside so they are all visible. If it can be made to<br clear="none">
> produce a scaled symbol based on the number of underlying points that would<br clear="none">
> be cool.That would also be a good time to change its name to 'Custer or<br clear="none">
> displace' or something.<br clear="none">
<br clear="none">
</div>I think that was what the renderer did originally, but nowadays it<br clear="none">
also groups points within configured distance. Unfortunately it always<br clear="none">
tries to draw a circle around the clustered point with original<br clear="none">
symbols. If we introduced few rendering options, it would be more<br clear="none">
useful:<br clear="none">
- draw just the clustered symbol for the whole group<br clear="none">
- scale the clustered symbol depending on the number of points inside<br clear="none">
<br clear="none"></blockquote><div><br clear="none"></div></div></div><div>Yeah that should do it!</div><div><br clear="none"></div></div></div></div></blockquote><div><br clear="none"></div><div>I tested with a large point dataset (geonames ~3.5 million records). Basically enabling the point displacement renderer on that layer kills (or takes so long I killed it) QGIS. Since the essence of clustering is to speed up rendering times and reduce visual clutter, I suspect simple tweaks to the renderer would not be enough.</div>
<div><br clear="none"></div><div>Regards</div><div><br clear="none"></div><div>Tim</div><div><br clear="none"></div><div> </div><blockquote style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">
<div>
<div><div></div><div>Regards</div><div><br clear="none"></div><div>Tim</div><div> </div><blockquote style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Cheers<br clear="none">
<span><font color="#888888">Martin<br clear="none">
</font></span></blockquote></div><div><br clear="none"><br clear="all"><div><br clear="none"></div>-- <br clear="none"><div dir="ltr">Tim Sutton - QGIS Project Steering Committee Member<br clear="none">==============================================<br clear="none">
Please do not email me off-list with technical<br clear="none">
support questions. Using the lists will gain<br clear="none">more exposure for your issues and the knowledge<br clear="none">surrounding your issue will be shared with all.<br clear="none"><br clear="none">Irc: timlinux on #qgis at <a rel="nofollow" shape="rect" href="http://freenode.net/" target="_blank">freenode.net</a><div>
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</div></blockquote></div><div><br clear="none"><br clear="all"><div><br clear="none"></div>-- <br clear="none"><div dir="ltr">Tim Sutton - QGIS Project Steering Committee Member<br clear="none">==============================================<br clear="none">
Please do not email me off-list with technical<br clear="none">
support questions. Using the lists will gain<br clear="none">more exposure for your issues and the knowledge<br clear="none">surrounding your issue will be shared with all.<br clear="none"><br clear="none">Irc: timlinux on #qgis at <a rel="nofollow" shape="rect" href="http://freenode.net/" target="_blank">freenode.net</a><br clear="none">
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</div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div dir="ltr">Tim Sutton - QGIS Project Steering Committee Member<br>==============================================<br>Please do not email me off-list with technical<br>
support questions. Using the lists will gain<br>more exposure for your issues and the knowledge<br>surrounding your issue will be shared with all.<br><br>Irc: timlinux on #qgis at <a href="http://freenode.net" target="_blank">freenode.net</a><br>
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