Hello Deon, For Spatialite you can check this:
http://www.gaia-gis.it/spatialite-3.0.0-BETA/spatialite-cookbook/index.html#common For Postgis, here is a good place to start: http://workshops.boundlessgeo.com/postgis-intro/ To use QGIS to read Postgis and Spatialite, in the users manual, see this links: http://www.qgis.org/en/docs/user_manual/working_with_vector/supported_data.html#postgis-layers http://www.qgis.org/en/docs/user_manual/working_with_vector/supported_data.html#spatialite-layers http://www.qgis.org/en/docs/user_manual/plugins/plugins_db_manager.html Hope this helps, Alexandre On Fri, Nov 1, 2013 at 4:32 AM, Pretorius Deon - Lieutenant Colonel < [email protected]> wrote: > Hi Alexandre,**** > > ** ** > > **1. **Thanks a lot for the info as I am new to QGIS, I will try it > out.**** > > **2. **Please tell me where can I learn more about Postgis and > Spatialite as well as on how to use SQL and as to what phrases to use, and > how can I learn more about it.**** > > ** ** > > ** ** > > With Respect,**** > > Deon**** > > ** ** > > *From:* Alexandre Neto [mailto:[email protected]] > *Sent:* 31 October 2013 01:23 PM > *To:* Pretorius Deon - Lieutenant Colonel > *Cc:* [email protected] > *Subject:* Re: [Qgis-user] Field Calculator/Python Plugins**** > > ** ** > > Hello Pretorius,**** > > ** ** > > 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.**** > > ** ** > > For that purpose I believe that Group Stats Plugin [1] is what you need.** > ** > > ** ** > > 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. > **** > > ** ** > > [1] http://plugins.qgis.org/plugins/GroupStats/**** > > ** ** > > Hope this helped,**** > > ** ** > > Alexandre Neto**** > > ** ** > > On Thu, Oct 31, 2013 at 7:43 AM, Pretorius Deon - Lieutenant Colonel < > [email protected]> wrote:**** > > Hi,**** > > 1. Where can I learn more about on how to use the Field calculator > as well as the Python Plugins as Iam new to this.**** > > 2. 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: > **** > > 3. How can I now calculate what the average percentage are per > Small_Place_Code and also what the results will be for each district?**** > > **** > > Small_Place_Code**** > > Districk_Name**** > > Small_Place_Areakm2**** > > District_AreaKM2**** > > Unemployment_Rate%**** > > *1112***** > > *Hamilton***** > > *0.0254***** > > *2.1753***** > > *6.21***** > > 1113**** > > Hamilton**** > > 0.1254**** > > 2.1753**** > > 4.25**** > > *1114***** > > *Hamilton***** > > *2.0245***** > > *2.1753***** > > *21.21***** > > *1112***** > > *Queens***** > > *0.0045***** > > *4.4316***** > > *6.21***** > > *1114***** > > *Queens***** > > *0.215***** > > *4.4316***** > > *21.21***** > > 3333**** > > Queens**** > > 0.2121**** > > 4.4316**** > > 4.35**** > > 3333**** > > Queens**** > > 4.000**** > > 4.4316**** > > 5.69**** > > **** > > Regards**** > > Deon**** > > **** > > **** > > **** > > > _______________________________________________ > Qgis-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-user**** > > ** ** >
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