<br><br><div class="gmail_quote">On Tue, Sep 27, 2011 at 8:10 PM, Martin Dobias <span dir="ltr"><<a href="mailto:wonder.sk@gmail.com">wonder.sk@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">On Tue, Sep 27, 2011 at 4:18 PM, Mohammed Rashad<br>
<<a href="mailto:mohammedrashadkm@gmail.com">mohammedrashadkm@gmail.com</a>> wrote:<br>
> Hi All,<br>
> I am developing tiled vector rendering in OSSIM. I like the Qgis vector<br>
> rendering system<br>
> point.shp contains 9,99,999 points which are generated by grass for using<br>
> v.random and ~27MB in size<br>
> roads.shp contains 2,28,068 linestrings and is ~50MB in size<br>
> these point.shp and roads.shp data gets rendered in ~10 sec<br>
> When I read vector using ogr and parse feature and draw point/linestring my<br>
> application taking about 40 sec to render point.shp<br>
> and<br>
> I am using Qt4 with QPainter not QGraphicsView<br>
> How came this time gap?<br>
<br>
</div>Most likely you have some inefficiencies in your implementation.<br></blockquote><div>Can you tell where i have inefficiencies I do direct rendering Qt Painter and OGR? </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im"><br>
> i see Rtree and pal libs in src/core source code<br>
> Does they have any role in rendering?<br>
<br>
</div>No - unless you also draw labels.<br>
<div class="im"><br>
> Does QGIS Rendering uses threading?<br>
<br>
</div>No - only in threading branch which has not yet been integrated.<br>
<div class="im"><br>
> How to get a minimal of QGIS code to hack it and build a new vector<br>
> rendering because I need it to make it tiled rendering vectors?<br>
<br>
</div>You can use qgis_core library to do tiled drawing.<br>
<div class="im"><br>
> How to improve performance in rendering without qgis?<br>
<br>
</div>Learn how to profile programs - i.e. get time spent in individual<br>
functions, analyze the results and fix the places where most of the<br>
time is spent.<br></blockquote><div><br></div><div>How to do profiling? how is works? please tell me some samples for profiling.. </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<font color="#888888"><br>
Martin<br>
</font></blockquote></div><br><br clear="all"><div><br></div>-- <br><div><font face="arial, helvetica, sans-serif">Regards,</font></div><font face="arial, helvetica, sans-serif"> Mohammed Rashad K M</font><div><font face="arial, helvetica, sans-serif"> M.S. (By Research) student<br>
Lab for Spatial Informatics<br> Department of CSE<br> International Institute of Information Technology</font></div><div><font face="arial, helvetica, sans-serif"> Hyderabad, India</font></div><br>