[postgis-users] QGIS - PostGIS - ArcGIS Interaction

[David Fawcett]

James,

There a couple of SQL plugins for QGIS.  They allow you to visualize
spatial features via 'ad hoc' queries (not whole tables).

I am pretty sure that I used the RT_SQL plugin.  Here is a link to
some info:  http://underdark.wordpress.com/2010/10/16/visualizing-postgis-queries-in-qgis-using-rt-sql-layer-plugin/

No need to buy a $10,000 proprietary desktop GIS...

David.

On Wed, Jun 15, 2011 at 1:33 PM, James David Smith
<james.david.smith at gmail.com> wrote:
> Dear Cristian & David,
>
> Thanks alot for your responses.
>
> Cristian - I don't have money to buy additional software
> unfortunately. With regard to 'view' I actually don't know what this
> is. I'm a bit of a beginner. I wonder if I made a 'view' whether I
> could then query that view with QGIS. Something for me to look into...
>
> David - That looks like a good idea... but when adding data to QGIS
> you can only select the whole table (I think) and then you manually
> enter the 'WHERE' clause in a dialog box. I guess I could run the
> query you suggest in PostgreSQL and save it into another table... and
> then link QGIS to the new table. Though it all starts to get a bit
> convoluted if I have to do that every time I want to look at some data
> in QGIS...
>
> Cheers
>
> James
>
>
>
> On 15 June 2011 19:16, David Fawcett <david.fawcett at gmail.com> wrote:
>> This is what is really cool about using a database to store your data...
>>
>> Change your query to:
>>
>> SELECT mycol1,
>>             mycol2,
>>             date_time_of_arrival as dt_arrive,
>>             date_time_of_departure as dt_depart,
>>              the_geom
>> FROM incidents
>> WHERE urgency = 'Immediate'
>> AND date_time_of_arrival - date_time_unit_assigned > '00:12:00'
>>
>> Note: you will need to specify the names of the columns that you are
>> interested in.
>>
>>
>> On Wed, Jun 15, 2011 at 12:58 PM, James David Smith
>> <james.david.smith at gmail.com> wrote:
>>> Dear all,
>>>
>>> I appreciate that this is more of a QGIS query, but I think that the
>>> route of the problem might be in PostGIS, so... I have opened QGIS and
>>> ran the query on my PostGIS table as below:
>>>
>>> SELECT * FROM incidents
>>> WHERE urgency = 'Immediate'
>>> AND date_time_of_arrival - date_time_unit_assigned > '00:12:00'
>>>
>>> This gives me 33 points in QGIS. Great. I would now however like to
>>> save this as a ShapeFile for use in ArcGIS with which I am more
>>> familiar, but when I try to SAVE AS from QGIS I am given the following
>>> error....
>>>
>>> Export to vector file failed.
>>> Error: trimming attribute name 'date_time_of_arrival' to ten
>>> significant characters produces duplicate column name.
>>>
>>> I am guessing that the problem here is that ESRI shapefiles can only
>>> deal with column names that are ten characters long...? And that as I
>>> also have a column called 'date_time_of_departure', when QGIS trims
>>> this column it ends up with two columns called the same thing?  Is
>>> there a way around this? I realise I could rename the column in QGIS,
>>> but I actually have around 45 columns in the table and this problem
>>> will occur with about 15 pairs of them I think. I guess there is no
>>> simple answer... but thought I'd ask.
>>>
>>> Cheers
>>>
>>> James
>>> _______________________________________________
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>>> postgis-users at postgis.refractions.net
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>
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