<div dir="ltr"><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Question</div><div class="gmail_default" style="font-family:georgia,serif">Does the dissolve process time exponentially increase with the number of polygons being processed or is it linear?<br></div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Background</div><div class="gmail_default" style="font-family:georgia,serif">Dear All</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">I am using QGIS 2.14 64 on i7 laptop in particular I have been dissolving a polygon file of around 20,000 individual polygons.</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">This using the standard menu</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Vector / Geoprocessing Tools / Dissolve</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">and opting for dissolve all for the Dissolve field</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Works great - it has been taking around 36 hours for 20,000 polygons. </div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Does the dissolve process time exponentially increase with the number of polygons being processed or is it linear?<br></div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Its a great option but I could see that I might want to do the dissolve at a national level and I could see my computer being tied up for a few weeks!</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Thanks in advance</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Mark</div><div class="gmail_default" style="font-family:georgia,serif">Edinburgh</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif"><br></div></div>