[postgis-users] QGIS - PostGIS - ArcGIS Interaction

Andreas Neumann a.neumann at carto.net
Thu Jun 16 05:39:34 PDT 2011


 Hi James,

 Thanks for the explanation. ArcGIS is still more powerful than QGIS, 
 but for many tasks QGIS is already good enough and it is rapidly 
 improving. For basic data editing and map publishing, the current QGIS 
 version is already quite good. Analysis tools are also improving 
 constantly. Of course 3D is still a weakness of QGIS ... The discussion 
 is a bit offtopic for the Postgis mailinglist anyway ...

 If you decide at one point to give QGIS a try, feel free to ask for 
 support at the QGIS users mailinglist. QGIS and Postgis is a very good 
 team usually.

 Andreas

 On Thu, 16 Jun 2011 13:18:33 +0100, James David Smith wrote:
> Hi Andreas,
>
> I'm sure that QGIS could do exactly what ArcGIS can do, it's just 
> that
> I do not have time at the moment to learn how. I am familiar with
> ArcGIS at the moment, so while I appreciate that is a poor excuse, 
> I'm
> going to keep using ArcGIS for the time being. Maybe later this year 
> I
> will learn more QGIS.
>
> Best wishes
>
> James
>
> On 16 June 2011 12:34, Andreas Neumann <a.neumann at carto.net> wrote:
>> Hi James,
>>
>> Glad you found a good solution for your problem.
>>
>> Of course we'd like to know what keeps you from using QGIS instead 
>> of
>> ArcGIS? Where would QGIS have to improve that you would consider 
>> using it?
>>
>> Thanks,
>> Andreas
>>
>> On Thu, 16 Jun 2011 12:23:13 +0100, James David Smith wrote:
>>>
>>> Dear all,
>>>
>>> Thank you so much for your help.
>>>
>>> shp2pgsql - I didn't realise it automaticaly renamed columns. 
>>> Awesome.
>>> I'll use that.
>>>
>>> ArcGIS 10 - I'm on 9 unfortunately. No access to 10 at the moment.
>>>
>>> RT  SQL - I glanced at that the other day and they seem to have
>>> stopped supporting ArcGIS 9, and also you had to pay for anything 
>>> more
>>> than 100 rows of data I think? I may have read that incorrectly, 
>>> but
>>> the shp2pgsql solution seems good so I'll just go with that anyway.
>>>
>>> Cheers all, this list is awesome!
>>>
>>> James :-)
>>>
>>>
>>> On 15 June 2011 21:44, David Fawcett <david.fawcett at gmail.com> 
>>> wrote:
>>>>
>>>> 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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>> --
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>> Andreas Neumann
>> Böschacherstrasse 10A
>> 8624 Grüt (Gossau ZH)
>> Switzerland
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