AW: Re: [Qgis-user] New PostGIS SQL Query Editor Plugin

[Düster Horst]

John,
 
I created the plugin due to the lack of possibility to visualize PostGIS
SQL Queries with resultant tables containing geometry columns. In
principle it should have a similar behaviour like the PgAdmin3 SQL
Editor. With the difference that the new plugin creates a geographical
view at the result too. 
 
Mini docmentation:
1. You have to define a PostGIS connection with the PostGIS Connector
2. When you start the plugin for the first time, it will ask for a
temp-path because it has to store the resultant shape files into a
directory. For further sessions this directory will be used until you
change it with the ... button
3. select the former defined PostGIS connectin
4. Under the assumption you have a PostGIS Table called example with one
geometry-column you can use the plugin to execute the following query:
 
select * from example 
 
when you hit the execute button or alternatively F5 the query is
executed and it produces a shape-file with the query result. But my
simple example doesn't make much sense. The use of the plugin makes
sense when you develop complex queries with joins, aggregations, filter,
functions etc. In this case you are able to develop your query and to
view the result directly and very easy. I think it is very helpful.
 
>Also, the plugin asks for a temporary directory to store files in, but
it seems that you need a permanent directory to work from. This is where
I am confused. Is this meant to perform queries on >existing postgis
tables, or is it meant to query a shapefile and then load it into
postgis? If the former, how does it improve on adding a postgis layer
and performing the query there? 
In many cases when you develop spatial queries it is helpful to see the
result directly. Thus you have to save the query-result temporarily many
times until you have finished the development process. Than you can take
your query and make a view from it into the database, which you can load
directly from PostGIS via Postgres connector of course. The idea is to
have a developement tool it is not the idea to create persistent
queries. If you like to save your temporary query result to a non
temporary place, please use the QGIS save as shapefile command.
 
I hope that the intension and the use of the plugin will be a little
more precised.
 
Regrads
Horst
 

------------------------------------------------ 

Dr. Horst Düster 
Stv. Amtschef / GIS-Koordinator 

Kanton Solothurn 
Bau- und Justizdepartement 
Amt für Geoinformation 
SO!GIS Koordination 
Rötistrasse 4 
CH-4501 Solothurn 

Telefon ++41(0)32 627 25 32 
Telefax ++41(0)32 627 22 14 

mailto:horst.duester at bd.so.ch 
http://www.agi.so.ch 

 

   -----Ursprüngliche Nachricht-----
   Von: John C. Tull [mailto:john.tull at wildnevada.org]
   Gesendet am: Donnerstag, 12. März 2009 17:47
   An: Düster Horst
   Cc: qgis-user
   Betreff: Re: [Qgis-user] New PostGIS SQL Query Editor Plugin
   

   Düster, 

   Do you have any documentation on how to use this? I gave it a go this
   morning, but a simple query statement did not work. What would be a
   snippet that would work in the query editor given that one has a
   table called "example" in a database called postgis with public
   schema on a local server?
   
   
   Also, the plugin asks for a temporary directory to store files in,
   but it seems that you need a permanent directory to work from. This
   is where I am confused. Is this meant to perform queries on existing
   postgis tables, or is it meant to query a shapefile and then load it
   into postgis? If the former, how does it improve on adding a postgis
   layer and performing the query there? 

   Cheers,
   John

   On Mar 12, 2009, at 1:36 AM, Düster Horst wrote:


      
      I just uploaded the new PostGIS SQL Query Editor Plugin to the
      QGIS User-Contributed Python Plugin Repository. The aim of the
      plugin is to edit and perform any spatial PostGIS query from an
      editor environment. After successful execution of a query the
      result will be loaded from shape file to MapCanvas. The plugin
      works provided that pgsql2shp is installed and the path to
      pgsql2shp is defined in the system PATH environment.

      I hope that the plugin will be helpful for you. I'm looking
      forward for any comment.

      Regards

      Dr. Horst Düster
      Stv. Amtschef / GIS-Koordinator

      Kanton Solothurn
      Bau- und Justizdepartement
      Amt für Geoinformation
      SO!GIS Koordination
      Rötistrasse 4
      CH-4501 Solothurn

      Telefon ++41(0)32 627 25 32
      Telefax ++41(0)32 627 22 14

      mailto:horst.duester at bd.so.ch
      http://www.agi.so.ch

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