[Qgis-user] Field Calculator/Python Plugins

[Alexandre Neto]

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 <
PretoriusDeon at saps.gov.za> 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:senhor.neto at gmail.com]
> *Sent:* 31 October 2013 01:23 PM
> *To:* Pretorius Deon - Lieutenant Colonel
> *Cc:* qgis-user at lists.osgeo.org
> *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 <
> PretoriusDeon at saps.gov.za> 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
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user****
>
> ** **
>
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