[Geoserver-users] Union function

Crawford_Jr_Stephen · March 12, 2007, 8:04pm

I was incorrect in calling them layers. Each of those is actually a geometry…each is one record in a feature layer. I guess what I really need is just an example of how to write the filter for the union function…for wms or wfs…I just can’t get my head around the syntax of some of these filters.

How would I write the filter for “(select the_geom where name=name1) union (select the_geom where name=name2)”? …it sounds so simple but I just cant figure it out!

Thanks Again,
Steve

On Mon, 12 Mar 2007 15:24:51 -0400 Chris Holmes wrote:

I don't believe that function is built for unioning layers.  It's
just 
for doing a union of a geometry, I believe, from the JTS library.  I

could be wrong, but I just don't think you can call two layers at
once 
for it.

I think that WMS is limited in this front, to do
it in the OGC way I 
think would be to get a Web Processing Service to do
the union, and then 
WMS of the results.

Chris

Stephen Crawford wrote:
> All,
> 
> I'm trying to
see the union of two layers via wms.  When I try SLD_BODY=
> 
>
<StyledLayerDescriptor>
> 	<NamedLayer>
> 
<Name>cei:breeding</Name> 
> 		<UserStyle>
> 
		<Name>myUnion</Name>
> 				<FeatureTypeStyle>
> 					<Rule> 
> 						<Filter>
> 						
<Function
> name="union"> 
> 	
>
<PropertyIsEqualTo>
> 	
>
<PropertyName>sci_name</PropertyName>
> 	
>
<Literal>Accipiter cooperii</Literal>
> 	
>
</PropertyIsEqualTo>
> 	
> <PropertyIsEqualTo>
> 	
> <PropertyName>sci_name</PropertyName>
> 

> <Literal>Buteo jamaicensis</Literal>
> 	
> </PropertyIsEqualTo>
> 							</Function> 
>
						</Filter>
> 						<PolygonSymbolizer>
> 					
	<Fill>
> 	
> <CssParameter
name="fill">#fe9929</CssParameter>
> 	
>
<CssParameter name="fill-opacity">1</CssParameter> 
> 							</Fill>
> 						</PolygonSymbolizer>
> 					</Rule> 
> 				</FeatureTypeStyle>
> 	
</UserStyle>
> 	</NamedLayer>
>
</StyledLayerDescriptor>
> 
> I get the union of ALL the
features in the layer;  I just want to get the
> union the polys where
sci_name=species1 and sci_name=species2.  Any ideas on
> how I should
write this query?
> 
> Thanks,
> Steve
> 
> Stephen Crawford
> Center for Environmental Informatics
> GeoVISTA Center
> The Pennsylvania State University
>
814.865.9905
> src176@anonymised.com
> 
> 
> -------------------------------------------------------------------------
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-- 
Chris Holmes
The Open Planning Project
[http://topp.openplans.org](http://topp.openplans.org)

---

cholmes.vcf

Stephen Crawford
GeoVISTA Center
Center for Environmental Informatics
src176@anonymised.com

Chris_Holmes1 · March 12, 2007, 8:13pm

Sorry, I don't know that anyone has actually used it. The 'functions' are basically dumps of some java classes, that take some arguments that get passed in. To figure it out you'll probably have to look at the source, and some of it may be broken. If you do figure it out it'd be great to help document it.

Sorry I can't be more helpful.

Chris

STEPHEN CRAWFORD wrote:

I was incorrect in calling them layers. Each of those is actually a geometry....each is one record in a feature layer. I guess what I really need is just an example of how to write the filter for the union function....for wms or wfs...I just can't get my head around the syntax of some of these filters.

How would I write the filter for "(select the_geom where name=name1) union (select the_geom where name=name2)"? ....it sounds so simple but I just cant figure it out!

Thanks Again,
Steve

On Mon, 12 Mar 2007 15:24:51 -0400 Chris Holmes wrote:

    I don't believe that function is built for unioning layers. It's
    just for doing a union of a geometry, I believe, from the JTS library. I

    could be wrong, but I just don't think you can call two layers at
    once for it.

    I think that WMS is limited in this front, to do
    it in the OGC way I think would be to get a Web Processing Service to do
    the union, and then WMS of the results.

    Chris

    Stephen Crawford wrote:
    > All,
    > > I'm trying to
    see the union of two layers via wms. When I try SLD_BODY=
    > >
    <StyledLayerDescriptor>
    > <NamedLayer>
    > <Name>cei:breeding</Name> > <UserStyle>
    > <Name>myUnion</Name>
    > <FeatureTypeStyle>
    > <Rule> > <Filter>
    >
    <Function
    > name="union"> >
    >
    <PropertyIsEqualTo>
    >
    >
    <PropertyName>sci_name</PropertyName>
    >
    >
    <Literal>Accipiter cooperii</Literal>
    >
    >
    </PropertyIsEqualTo>
    >
    > <PropertyIsEqualTo>
    >
    > <PropertyName>sci_name</PropertyName>
    >

    > <Literal>Buteo jamaicensis</Literal>
    >
    > </PropertyIsEqualTo>
    > </Function> >
                </Filter>
    > <PolygonSymbolizer>
    >
      <Fill>
    >
    > <CssParameter
    name="fill">#fe9929</CssParameter>
    >
    >
    <CssParameter name="fill-opacity">1</CssParameter> > </Fill>
    > </PolygonSymbolizer>
    > </Rule> > </FeatureTypeStyle>
    >
    </UserStyle>
    > </NamedLayer>
    >
    </StyledLayerDescriptor>
    > > I get the union of ALL the
    features in the layer; I just want to get the
    > union the polys where
    sci_name=species1 and sci_name=species2. Any ideas on
    > how I should
    write this query?
    > > Thanks,
    > Steve
    > > Stephen Crawford
    > Center for Environmental Informatics
    > GeoVISTA Center
    > The Pennsylvania State University
    >
    814.865.9905
    > src176@anonymised.com <main.cgi>
    > > > -------------------------------------------------------------------------
    > Take Surveys. Earn Cash. Influence the Future of IT
    > Join SourceForge.net's Techsay panel and you'll get the chance to
    share your
    > opinions on IT & business topics through brief surveys-and earn cash
    > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
    > _______________________________________________
    > Geoserver-users mailing list
    > Geoserver-users@lists.sourceforge.net <main.cgi>
    > https://lists.sourceforge.net/lists/listinfo/geoserver-users
    > > >

    -- Chris Holmes
    The Open Planning Project
    http://topp.openplans.org

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

    cholmes.vcf <get_file.cgi?dir=attach&fname=cholmes%2evcf>

Stephen Crawford
GeoVISTA Center
Center for Environmental Informatics
src176@anonymised.com
!DSPAM:1003,45f5b419213291365099012!

--
Chris Holmes
The Open Planning Project
http://topp.openplans.org

Sebastian_Schmitz · March 22, 2007, 9:48am

Hi,
Am I right in stating that ogc:Functions provided by GeoServer through its capabilities are not documented? I thought they would have to be described in one of the specs, most importantly in FilterEncoding, but they are not, thus they are not standardised, right? They are merely 'named procedures that perform a distinct computation'. However, this computation is not nearer described...?
Anyone know of plans to standardise ogc:functions a bit more, e.g. enhance WFS or move that ogc:functions stuff to WPS or describe it using SensorML or sth. alike?

Cheers

Sebastian

Chris Holmes schrieb:

Sorry, I don't know that anyone has actually used it. The 'functions' are basically dumps of some java classes, that take some arguments that get passed in. To figure it out you'll probably have to look at the source, and some of it may be broken. If you do figure it out it'd be great to help document it.

Sorry I can't be more helpful.

Chris

STEPHEN CRAWFORD wrote:

I was incorrect in calling them layers. Each of those is actually a geometry....each is one record in a feature layer. I guess what I really need is just an example of how to write the filter for the union function....for wms or wfs...I just can't get my head around the syntax of some of these filters.

How would I write the filter for "(select the_geom where name=name1) union (select the_geom where name=name2)"? ....it sounds so simple but I just cant figure it out!

Thanks Again,
Steve

On Mon, 12 Mar 2007 15:24:51 -0400 Chris Holmes wrote:

    I don't believe that function is built for unioning layers. It's
    just for doing a union of a geometry, I believe, from the JTS library. I

    could be wrong, but I just don't think you can call two layers at
    once for it.

    I think that WMS is limited in this front, to do
    it in the OGC way I think would be to get a Web Processing Service to do
    the union, and then WMS of the results.

    Chris

    Stephen Crawford wrote:
    > All,
    > > I'm trying to
    see the union of two layers via wms. When I try SLD_BODY=
    > >
    <StyledLayerDescriptor>
    > <NamedLayer>
    > <Name>cei:breeding</Name> > <UserStyle>
    > <Name>myUnion</Name>
    > <FeatureTypeStyle>
    > <Rule> > <Filter>
    > <Function
    > name="union"> > >
    <PropertyIsEqualTo>
    > >
    <PropertyName>sci_name</PropertyName>
    > >
    <Literal>Accipiter cooperii</Literal>
    > >
    </PropertyIsEqualTo>
    > > <PropertyIsEqualTo>
    > > <PropertyName>sci_name</PropertyName>
    >
    > <Literal>Buteo jamaicensis</Literal>
    > > </PropertyIsEqualTo>
    > </Function> >
                            </Filter>
    > <PolygonSymbolizer>
    > <Fill>
    > > <CssParameter
    name="fill">#fe9929</CssParameter>
    > >
    <CssParameter name="fill-opacity">1</CssParameter> > </Fill>
    > </PolygonSymbolizer>
    > </Rule> > </FeatureTypeStyle>
    > </UserStyle>
    > </NamedLayer>
    >
    </StyledLayerDescriptor>
    > > I get the union of ALL the
    features in the layer; I just want to get the
    > union the polys where
    sci_name=species1 and sci_name=species2. Any ideas on
    > how I should
    write this query?
    > > Thanks,
    > Steve
    > > Stephen Crawford
    > Center for Environmental Informatics
    > GeoVISTA Center
    > The Pennsylvania State University
    >
    814.865.9905
    > src176@anonymised.com <main.cgi>
    > > > -------------------------------------------------------------------------

    > Take Surveys. Earn Cash. Influence the Future of IT
    > Join SourceForge.net's Techsay panel and you'll get the chance to
    share your
    > opinions on IT & business topics through brief surveys-and earn cash
    > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV

    > _______________________________________________
    > Geoserver-users mailing list
    > Geoserver-users@lists.sourceforge.net <main.cgi>
    > https://lists.sourceforge.net/lists/listinfo/geoserver-users
    > > >
    -- Chris Holmes
    The Open Planning Project
    http://topp.openplans.org

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

    cholmes.vcf <get_file.cgi?dir=attach&fname=cholmes%2evcf>

Stephen Crawford
GeoVISTA Center
Center for Environmental Informatics
src176@anonymised.com
!DSPAM:1003,45f5b419213291365099012!

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Andrea_Aime3 · March 22, 2007, 2:39pm

Sebastian Schmitz ha scritto:

Hi,
Am I right in stating that ogc:Functions provided by GeoServer through its capabilities are not documented?

Fully right. The only way to understand what they do and what arguments
they require is to go into the geotools gt2-main source code and
inspect the FilterFunction_* classes, which have been automatically
generated too, thought I don't know the details (David Blasby created them afaik).

I thought they would have to be described in one of the specs, most importantly in FilterEncoding, but they are not, thus they are not standardised, right? They are merely 'named procedures that perform a distinct computation'. However, this computation is not nearer described...?
Anyone know of plans to standardise ogc:functions a bit more, e.g. enhance WFS or move that ogc:functions stuff to WPS or describe it using SensorML or sth. alike?

I'm not aware of anything like that, but yeah, it should be something to
do. At least, we should have a list of functions and descriptions of them in the documentation.

Cheers
Andrea

Justin_Deoliveira · March 22, 2007, 3:38pm

Sebastian Schmitz wrote:

Hi,
Anyone know of plans to standardise ogc:functions a bit more, e.g. enhance WFS or move that ogc:functions stuff to WPS or describe it using SensorML or sth. alike?

Not sure, you will probably get a better answer on the wfs-dev mailing list. wfs-dev@anonymised.com

-Justin

Cheers

Sebastian

Chris Holmes schrieb:

Sorry, I don't know that anyone has actually used it. The 'functions' are basically dumps of some java classes, that take some arguments that get passed in. To figure it out you'll probably have to look at the source, and some of it may be broken. If you do figure it out it'd be great to help document it.

Sorry I can't be more helpful.

Chris

STEPHEN CRAWFORD wrote:

I was incorrect in calling them layers. Each of those is actually a geometry....each is one record in a feature layer. I guess what I really need is just an example of how to write the filter for the union function....for wms or wfs...I just can't get my head around the syntax of some of these filters.

How would I write the filter for "(select the_geom where name=name1) union (select the_geom where name=name2)"? ....it sounds so simple but I just cant figure it out!

Thanks Again,
Steve

On Mon, 12 Mar 2007 15:24:51 -0400 Chris Holmes wrote:

    I don't believe that function is built for unioning layers. It's
    just for doing a union of a geometry, I believe, from the JTS library. I

    could be wrong, but I just don't think you can call two layers at
    once for it.

    I think that WMS is limited in this front, to do
    it in the OGC way I think would be to get a Web Processing Service to do
    the union, and then WMS of the results.

    Chris

    Stephen Crawford wrote:
    > All,
    > > I'm trying to
    see the union of two layers via wms. When I try SLD_BODY=
    > >
    <StyledLayerDescriptor>
    > <NamedLayer>
    > <Name>cei:breeding</Name> > <UserStyle>
    > <Name>myUnion</Name>
    > <FeatureTypeStyle>
    > <Rule> > <Filter>
    > <Function
    > name="union"> > >
    <PropertyIsEqualTo>
    > >
    <PropertyName>sci_name</PropertyName>
    > >
    <Literal>Accipiter cooperii</Literal>
    > >
    </PropertyIsEqualTo>
    > > <PropertyIsEqualTo>
    > > <PropertyName>sci_name</PropertyName>
    >
    > <Literal>Buteo jamaicensis</Literal>
    > > </PropertyIsEqualTo>
    > </Function> >
                            </Filter>
    > <PolygonSymbolizer>
    > <Fill>
    > > <CssParameter
    name="fill">#fe9929</CssParameter>
    > >
    <CssParameter name="fill-opacity">1</CssParameter>

                            </Fill>

    > </PolygonSymbolizer>
    > </Rule> > </FeatureTypeStyle>
    > </UserStyle>
    > </NamedLayer>
    >
    </StyledLayerDescriptor>
    > > I get the union of ALL the
    features in the layer; I just want to get the
    > union the polys where
    sci_name=species1 and sci_name=species2. Any ideas on
    > how I should
    write this query?
    > > Thanks,
    > Steve
    > > Stephen Crawford
    > Center for Environmental Informatics
    > GeoVISTA Center
    > The Pennsylvania State University
    >
    814.865.9905
    > src176@anonymised.com <main.cgi>
    > > > -------------------------------------------------------------------------

    > Take Surveys. Earn Cash. Influence the Future of IT
    > Join SourceForge.net's Techsay panel and you'll get the chance to
    share your
    > opinions on IT & business topics through brief surveys-and earn cash
    > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV

    > _______________________________________________
    > Geoserver-users mailing list
    > Geoserver-users@lists.sourceforge.net <main.cgi>
    > https://lists.sourceforge.net/lists/listinfo/geoserver-users
    > > >
    -- Chris Holmes
    The Open Planning Project
    http://topp.openplans.org

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

    cholmes.vcf <get_file.cgi?dir=attach&fname=cholmes%2evcf>

Stephen Crawford
GeoVISTA Center
Center for Environmental Informatics
src176@anonymised.com

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
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