[Qgis-user] QGISWebserver and PostGIS-Layer

Albin Blaschka albin.blaschka at standortsanalyse.net
Mon Nov 26 07:11:48 PST 2012 

Hello!

So, finally, I resolved my problem - it was twofold:
The main reason was a problem with the projection of the data, it was 
not properly projected (forgot to specify it for the import to 
postgis...) and secondly, I had to find the right bounding box...

A spontaneous idea: would it be possible to write up a few lines on the 
python console to spit out the correct string, directly usable for the 
bounding box (cut 'n copy) taken from the current map extent...? (Up to 
now, my python experience is close to zero...)

Thanks to Bernhard for his patience and his help!

Albin


Am 23.11.2012 09:40, schrieb Bernhard Ströbl:
> Hi Albin,
>
> be sure you reply to the list.
> It seems that QGIS desktop does not access the same server/same
> project/same layer as your request. Check the apache access.log and the
> GetMap request issued by QGIS desktop to find any differences.
>
> Bernhard
>
> Am 23.11.2012 09:32, schrieb Albin Blaschka:
>> Hi!
>>
>>
>> Am 23.11.2012 09:11, schrieb Bernhard Ströbl:
>>> Hi,
>>>
>>> do you get a map (and no white image) in QGIS desktop? If yes
>>> 1) your server is ok but your request is somehow wrong.
>>> 2) Check your access log and look at the GetMap-request that QGIS
>>> desktop sends. Compare it to your request.
>>>
>>> If no there is something misconfigured, e.g. the SRS of the layer does
>>> not match the SRS of the data, the database is not accessible from the
>>> server (check pg_hba.conf)....
>>>
>>
>> Thank you for your patience!
>> 1.) The map in QGIS Desktop is ok, no problems there! So, yes, the error
>> lies somewhere with my request.
>>
>> 2.) I just checked the PostgreSQL-log (PostgreSQL is running on the same
>> machine as Apache and is ok): There I found something strange and most
>> probably the cause for the error: Each time, I make a request via the
>> Mapserver, I get the error "column 'geom' does not exist" BUT in the
>> respective table, the geometry column is called "the_geom" and
>> registered with this name in the geometry_columns-table (I just chekced
>> that, too). In the qgs-file (the project file), it is also the_geom -
>> here the relevant part of the qgs-file:
>>
>> <projectlayers layercount="1">
>> <maplayer minimumScale="0" maximumScale="1e+08" geometry="Point"
>> type="vector" hasScaleBasedVisibilityFlag="0">
>> <id>verortung20121123083448551</id>
>> <datasource>dbname='mydatabase' host=myserver port=5432 user='myuser'
>> password='pwd' sslmode=allow key='gid' srid=4326 type=POINT
>> table="myschema"."verortung" (the_geom) sql=</datasource>
>>
>> I am "slightly" puzzled about that, I just start looking into that
>> issue...
>>
>> Mhmmm...
>> Thanks,
>> best regards,
>> Albin
>>
>>
>>
>>
>>
>>> Bernhard
>>>
>>> Am 23.11.2012 08:52, schrieb Albin Blaschka:
>>>> Hi!
>>>>
>>>>
>>>>
>>>> Am 23.11.2012 08:02, schrieb Bernhard Ströbl:
>>>>> Hi Albin,
>>>>>
>>>>> try
>>>>> http://myserver/cgi-bin/qgis_mapserv.fcgi?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&FORMAT=image/png&CRS=EPSG:4326&WIDTH=500&HEIGHT=500&LAYERS=mypostgislayer&BBOX=12.96,47.79,12.98,47.81
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> as a major change from 1.1.1 to 1.3.0 is the exchange of x and y
>>>>> coordinates or use VERSION=1.3.0 and exchange x and y coordinates of
>>>>> the
>>>>> BBOX
>>>>>
>>>>> if I understand you correctly you get an image as reply but the
>>>>> image is
>>>>> all white. So the server is running ok but there are no data in the
>>>>> place for which you request the map.
>>>>>
>>>>
>>>>
>>>> Yes, you understand correctly - I followed your example, but no
>>>> success...
>>>>
>>>> Is there a possibility to switch on some kind of logging, additionally
>>>> to the apache logging? In the apache logs, no errors or warnings or
>>>> similar appear...
>>>>
>>>> Thank you for your help!
>>>>
>>>> regards, Albin
>>>>
>>>>
>>>>
>>>>
>>>>>
>>>>> Am 22.11.2012 17:05, schrieb Albin Blaschka:
>>>>>>
>>>>>> Hello!
>>>>>>
>>>>>> Thank you for your answer!
>>>>>>
>>>>>>> the URL seems to lack the BBOX parameter (I think this is a
>>>>>>> necessary
>>>>>>> parameter in a GetMap request)
>>>>>>> Can you access the maps through QGIS desktop?
>>>>>>> What happens if you send a GetCapabilities request:
>>>>>>> http://myserver/cgi-bin/qgis_mapserv.fcgi?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetCapabilities
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> In QGIS Desktop, everything seems ok, the GetCapabilities-Request
>>>>>> looks
>>>>>> also ok - here the head of the answer cut 'n copied:
>>>>>>
>>>>>> <WMS_Capabilities version="1.3.0"
>>>>>> xsi:schemaLocation="http://www.opengis.net/wms
>>>>>> http://schemas.opengis.net/wms/1.3.0/capabilities_1_3_0.xsd"><Service><Name>WMS</Name><Title>QGIS-Server</Title><Abstract/><OnlineResource
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> xlink:type="simple"
>>>>>> xlink:href=""/><ContactInformation><ContactPersonPrimary><ContactPerson>Albin
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Blaschka</ContactPerson><ContactOrganization>LFZ
>>>>>> Raumberg-Gumpenstein</ContactOrganization></ContactPersonPrimary><ContactVoiceTelephone/><ContactElectronicMailAddress>albin.blaschka at raumberg-gumpenstein.at</ContactElectronicMailAddress></ContactInformation></Service>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> ...
>>>>>>
>>>>>> Concerning the BBOX:
>>>>>> I tried it with the following URL (for a small area close to the
>>>>>> town of
>>>>>> Salzburg), but again, no success, just a white canvas:
>>>>>>
>>>>>> http://myserver/cgi-bin/qgis_mapserv.fcgi?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image/png&CRS=EPSG:4326&WIDTH=500&HEIGHT=500&LAYERS=mypostgislayer&BBOX=12.96,47.79,12.98,47.81
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>> Albin
>>>>>>
>>>>>>>
>>>>>>> Bernhard
>>>>>>>
>>>>>>> Am 22.11.2012 16:12, schrieb Albin Blaschka:
>>>>>>>> Hello!
>>>>>>>>
>>>>>>>> I just started to use QGIS Server on an Ubuntu server, after
>>>>>>>> installation and basic configuration, I get a successful answer
>>>>>>>> of a
>>>>>>>> GetCapability-Request.
>>>>>>>>
>>>>>>>> Now, for my first "real" project, I have a question regarding the
>>>>>>>> QGIS
>>>>>>>> Server and PostGIS-Layers: If I enter the following URL in
>>>>>>>> firefox, I
>>>>>>>> just get a blank canvas, no layer:
>>>>>>>>
>>>>>>>> http://myserver/cgi-bin/qgis_mapserv.fcgi?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image/png&CRS=EPSG:4326&WIDTH=500&HEIGHT=500&LAYERS=mypostgislayer
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> What I have done so far:
>>>>>>>>
>>>>>>>> * I have set up a project in QGIS Desktop including a
>>>>>>>> PostGIS-Layer,
>>>>>>>> with the connection storing the full connection string (username
>>>>>>>> and
>>>>>>>> password), the layer is shown as it should be
>>>>>>>>
>>>>>>>> * I saved the QGIS project file and opend it in a text editor and
>>>>>>>> found
>>>>>>>> the credentials for the PostGIS-Layer
>>>>>>>>
>>>>>>>> * I copied the project file into the cgi-bin directory, chmod'ed it
>>>>>>>> even
>>>>>>>> to 777, just to get it going; trying it with the "map="-parameter
>>>>>>>> was
>>>>>>>> also not successfull...
>>>>>>>>
>>>>>>>> * The database server is the same box as the apache (Ubuntu Oneiric
>>>>>>>> 11.10, PostgreSQL 8.3.8, PostGIS Version 1.3; it is an
>>>>>>>> intranet-server,
>>>>>>>> not reachable from outside)
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> What have I done wrong?
>>>>>>>>
>>>>>>>> Thanks in advance,
>>>>>>>> best regards,
>>>>>>>> Albin
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> __________ Information from ESET Mail Security, version of virus
>>>>>>> signature database 7720 (20121122) __________
>>>>>>>
>>>>>>> The message was checked by ESET Mail Security.
>>>>>>> http://www.eset.com
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Qgis-user mailing list
>>>>>>> Qgis-user at lists.osgeo.org
>>>>>>> http://lists.osgeo.org/mailman/listinfo/qgis-user
>>>>>>
>>>>>
>>>>
>>>
>
>
>
>
> __________ Information from ESET Mail Security, version of virus
> signature database 7722 (20121122) __________
>
> The message was checked by ESET Mail Security.
> http://www.eset.com
>
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user

-- 
| Albin Blaschka, Mag.rer.nat.
| Etrichstrasse 26, A-5020 Salzburg
| * www.albinblaschka.info * www.thinkanimal.info *
| - It's hard to live in the mountains, hard but not hopeless!

More information about the Qgis-user mailing list