Hi,
WFS does actually support that somehow. The query needs just to contain
maxFeatures=1 with sortBy ascending/descending. This query returns a town with
highest population in 1999 (Helsinki, 515490). You can shorten the response by
including also the &propertyname parameter.
http://hip.latuviitta.org/cgi-bin/tinyows?service=wfs&version=1.1.0&request=GetFeature&typename=lv:mml_cityp&maxFeatures=1&sortBy=asulkm1999+D
This one returns a village with lowest population value (0, means missing data
in this case)
http://hip.latuviitta.org/cgi-bin/tinyows?service=wfs&version=1.1.0&request=GetFeature&typename=lv:mml_cityp&maxFeatures=1&sortBy=asulkm1999+A
I wouldn't trust that results from an unknown WFS server is right, though. I
guess that sorting with different backends ant together with filters is
generally very little tested. I am remembering that it worked OK for me with
Geoserver and PostGIS once I was playing with this sometimes.
Corresponding Geoserver document page is
http://docs.geoserver.org/stable/en/user/services/wfs/reference.html
Results comes from TinyOWS at the moment because my super cheap virtual server
does not have enough memory for running Geoserver, sorry for that.
-Jukka Rahkonen-
Martin Davis wrote:
WFS doesn't support aggregation in queries, only filtering. (In other words,
it's not functionally compatible with SQL).
However, you can do this by using a WPS process. Have a look at the
gs:Aggregate process.
On Thu, Dec 13, 2012 at 2:02 AM, zeliofern
<[email protected]<mailto:[email protected]>> wrote:
Hi Guys
i have gone through the documentation and it is said that ogc:max and
ogc:min function is just used to get max between provided numbers. also on
ogc and arcgis website it is said to use SortBy in WFS query filter.
i have 2 question :
1) does geoserver have support to use sortby in WFS filter query?
2)my requirement is to find the lowest and the highest value in a attribute
of layer published in geoserver
is there any WFS query function to do that?
--
View this message in context:
http://osgeo-org.1560.n6.nabble.com/WFS-query-to-find-lowest-and-highest-value-of-a-attribute-in-a-layer-tp5022702.html
Sent from the GeoServer - User mailing list archive at Nabble.com.
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