<div dir="ltr">Hello Pretorius,<div><br></div><div>Both field calculator and Python calculator, allows one to calculate values of columns, but does not affect the number of rows. What you need is to somehow group (sum, mean, etc...) field values by a certain column common value.</div>
<div><br></div><div>For that purpose I believe that Group Stats Plugin [1] is what you need.</div><div><br></div><div>Also If you are going to do lot of this kind of analysis, I would advice you to put your data in Postgis or Spatialite so you can run SQL queries. </div>
<div><br></div><div>[1] <a href="http://plugins.qgis.org/plugins/GroupStats/">http://plugins.qgis.org/plugins/GroupStats/</a><br></div><div><br></div><div>Hope this helped,</div><div><br></div><div>Alexandre Neto</div></div>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Oct 31, 2013 at 7:43 AM, Pretorius Deon - Lieutenant Colonel <span dir="ltr"><<a href="mailto:PretoriusDeon@saps.gov.za" target="_blank">PretoriusDeon@saps.gov.za</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-ZA" link="blue" vlink="purple"><div><p class="MsoNormal">Hi,<u></u><u></u></p><p style="margin-left:38.25pt">
<u></u><span>1.<span style="font:7.0pt "Times New Roman""> </span></span><u></u>Where can I learn more about on how to use the Field calculator as well as the Python Plugins as Iam new to this.<u></u><u></u></p>
<p style="margin-left:38.25pt"><u></u><span>2.<span style="font:7.0pt "Times New Roman""> </span></span><u></u>I need to determine the unemployment rate for each district. There are over 10 000 small_place_codes and just over 1000 district. The majority of the small places overlaps with districts so I did an intersection for the two layers. An example of the results are as follows:<u></u><u></u></p>
<p style="margin-left:38.25pt"><u></u><span>3.<span style="font:7.0pt "Times New Roman""> </span></span><u></u>How can I now calculate what the average percentage are per Small_Place_Code and also what the results will be for each district?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p><table border="1" cellspacing="0" cellpadding="0" style="border-collapse:collapse;border:none"><tbody><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal">Small_Place_Code<u></u><u></u></p></td><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">Districk_Name<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">Small_Place_Areakm2<u></u><u></u></p></td><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal">District_AreaKM2<u></u><u></u></p></td><td width="128" valign="top" style="width:95.8pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">Unemployment_Rate%<u></u><u></u></p>
</td></tr><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><u>1112<u></u><u></u></u></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><u>Hamilton<u></u><u></u></u></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><u>0.0254<u></u><u></u></u></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><u>2.1753<u></u><u></u></u></b></p></td><td width="128" valign="top" style="width:95.8pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><u>6.21<u></u><u></u></u></b></p></td></tr><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">1113<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">Hamilton<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">0.1254<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">2.1753<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.8pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">4.25<u></u><u></u></p>
</td></tr><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><i>1114<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>Hamilton<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>2.0245<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>2.1753<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.8pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>21.21<u></u><u></u></i></b></p></td></tr><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><u>1112<u></u><u></u></u></b></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><u>Queens<u></u><u></u></u></b></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><u>0.0045<u></u><u></u></u></b></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><u>4.4316<u></u><u></u></u></b></p>
</td><td width="128" valign="top" style="width:95.8pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><u>6.21<u></u><u></u></u></b></p>
</td></tr><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal"><b><i>1114<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>Queens<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>0.215<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>4.4316<u></u><u></u></i></b></p></td><td width="128" valign="top" style="width:95.8pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal"><b><i>21.21<u></u><u></u></i></b></p></td></tr><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">3333<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">Queens<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">0.2121<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">4.4316<u></u><u></u></p>
</td><td width="128" valign="top" style="width:95.8pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">4.35<u></u><u></u></p>
</td></tr><tr><td width="128" valign="top" style="width:95.75pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt"><p class="MsoNormal">3333<u></u><u></u></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal">Queens<u></u><u></u></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal">4.000<u></u><u></u></p></td><td width="128" valign="top" style="width:95.75pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal">4.4316<u></u><u></u></p></td><td width="128" valign="top" style="width:95.8pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt">
<p class="MsoNormal">5.69<u></u><u></u></p></td></tr></tbody></table><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">Regards<span class="HOEnZb"><font color="#888888"><u></u><u></u></font></span></p><span class="HOEnZb"><font color="#888888"><p class="MsoNormal">
Deon<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><u></u> <u></u></p></font></span></div></div><br>_______________________________________________<br>
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