[GeoSciML] using SLDs - big problem with OneGeology layer naming conventions

Alistair Ritchie RitchieA at landcareresearch.co.nz
Mon Oct 15 23:07:05 EDT 2012


Looking at the copies of the GSV WMS SLDs that I have* I note that we/they have always used a 'generic' sld:Name value (eg  <sld:Name>geology-lithology</sld:Name>). This allowed us to reuse the same SLD for multiple 1G WMS layers, say: AUS_VIC_GSV_50K_BLT and AUS_VIC_GSV_250K_BLT. The SLD is presented as a 'Style' inside each 1G WMS Layer and it is requested using the 'style' parameter in the GetMap request. (...&layers=AUS_VIC_GSV_250K_BLT&style=geology-lithology...)

Check out the layer style pairings here (noting that it only reuses the simple 'polygon' style): http://geology.data.vic.gov.au/services/onegeology/DPI_Bedrock_and_Superficial_Geology/wms?service=WMS&request=GetCapabilities

If you look at implementations such as Geoserver, SLDs are presented as a library of styles that can be bound to one or more WMS layers during configuration. As long as each layer has a property that matches that specified in the <ogc:PropertyName> element for each rule filter you are fine.

This has never caused any problems during implementation (or when I validated the SLDs). Is this possible technically incorrect? Reading the SLD 1.0 XSD if suggests it is - 'A NamedLayer is a layer of data that has a name advertised by a WMS.' (Although if I try to request a layer called 'geology-lithology' from the GSV 1G WMS it says there is no such layer.)

There seems to be a subtle distinction between a SLD layer and a WMS layer.

Cheers, Alistair

* I kept them as mementos and occasionally look at them and reminisce about working with geology data.

-----Original Message-----
From: geosciml-bounces+ritchiea=landcareresearch.co.nz at lists.opengeospatial.org [mailto:geosciml-bounces+ritchiea=landcareresearch.co.nz at lists.opengeospatial.org] On Behalf Of Steve Richard
Sent: Tuesday, 16 October 2012 15:06
To: Simon.Cox at csiro.au; geosciml at lists.opengeospatial.org
Subject: Re: [GeoSciML] using SLDs - big problem with OneGeology layer naming conventions

The WMS has to have a layer matching the sld:namedLayer element. It sort of makes sense I guess, since there's no concept of something like a feature type in the WMS capabilities--how do you match a layer definition in the SLD with a layer in the WMS...
So either OneGeology has to add a layer that has the same name in every service (e.g. geoPoly, GeoLine or something like that) as an SLD named layer target, or the client has to spin up different SLD's for each WMS call that it want to integrate using the SLD portrayal scheme....  I'm hoping someone out there has a better idea!

steve

> -----Original Message-----
> From: Simon.Cox at csiro.au [mailto:Simon.Cox at csiro.au]
> Sent: Monday, October 15, 2012 6:38 PM
> To: steve.richard at azgs.az.gov; geosciml at lists.opengeospatial.org
> Subject: RE: [GeoSciML] using SLDs - big problem with OneGeology layer
naming
> conventions
>
> Oh dear. SLD design does not allow re-use of SLDs for different data
instances?
> That would be broken (non-scalable).
>
> -----Original Message-----
> From: Steve Richard [mailto:steve.richard at azgs.az.gov]
> Sent: Tuesday, 16 October 2012 7:56 AM
> To: Cox, Simon (CESRE, Kensington); geosciml at lists.opengeospatial.org
> Subject: RE: [GeoSciML] using SLDs - big problem with OneGeology layer
naming
> conventions
>
> That's what I though initially, but after some research it looks like
> it
might
> actually be consistent with SLD design...
> stee
>
> > -----Original Message-----
> > From: Simon.Cox at csiro.au [mailto:Simon.Cox at csiro.au]
> > Sent: Monday, October 15, 2012 2:58 PM
> > To: geosciml at lists.opengeospatial.org; steve.richard at azgs.az.gov
> > Subject: RE: [GeoSciML] using SLDs - big problem with OneGeology
> > layer
> naming
> > conventions
> >
> > ESRI fail?
> >
> > Simon Cox
> > CSIRO
> >
> > Sent from my phone so please excuse typos.
> >
> > -----Original Message-----
> > From: Steve Richard [steve.richard at azgs.az.gov]
> > Received: Tuesday, 16 Oct 2012, 2:06
> > To: A mailing list for GeoSciML [geosciml at lists.opengeospatial.org]
> > Subject: [GeoSciML] using SLDs - big problem with OneGeology layer
> > naming conventions
> >
> >
> > Hi everyone-
> >
> > I've been trying to get SLD's assembled as examples for OneGeology
> services
> > using GeoSciML-portrayal. OneGeology requires WMS layers to be named
> > with
> a
> > pattern that results in layer names in each service being unique
> > (see http://www.onegeology.org/wmsCookbook/2_5.html), e.g.
> > USA_USGIN_3M_Lithostratigraphy.  From the experimenting I've done,
> > looking at the OGC spec, GeoServer, and ArcGIS server documentation,
> > it looks like
> the
> > 'sld:NamedLayer' value in an SLD has to match one of the layer names
> > in
> the
> > WMS you want to apply the SLD to.
> >
> > The effect is that the SLD will have to be customized for each
> > OneGeology
> WMS
> > you want to use it against, because the layer names will be unique
> > to each service.  This greatly complicates the work for generating a
> > client that
> uses SLD
> > to customize map portrayals from OneGeology services.
> >
> > Am I missing something here, or does oneGeology need to require
> > additional layers in each service that are named something like
> > SLD_lithology and
> SLD_age,
> > so one SLD file can be applied to multiple services....
> >
> > steve
> >
> >
> > Example:
> > WMS request:
> > http://services.azgs.az.gov/ArcGIS/services/OneGeology/AZGS_USGIN_Ge
> > ol
> > ogy
> /MapServer/WMSServer?request=GetMap&service=WMS&version=1.3.0&&CRS
> > =CRS:84&BBOX=-114,28,-
> > 66,45&WIDTH=1765&HEIGHT=1000&STYLES=geology-
> >
> lithology&FORMAT=image/png&LAYERS=USA_USGIN_3M_Lithostratigraphy&SL
> > D=http://schemas.usgin.org/schemas/slds/CGISedimentLithology0000.sld
> >
> > In the SLD:
> > <sld:StyledLayerDescriptor xmlns:gml="....">
> >             <sld:NamedLayer>
> >
> <sld:Name>USA_USGIN_3M_Lithostratigraphy</sld:Name>
> >                         <sld:UserStyle>
> >
> > <sld:Name>geology-lithology</sld:Name>
> > <rules...>
> >
> > In the WMS GetCapabilities:
> > <Layer>
> >         <Name>AZGS_USGIN_Geology</Name>
> >               <Title><![CDATA[AZGS USGIN Geology]]></Title>
> >               <CRS>....</CRS>
> >               <EX_GeographicBoundingBox>...</EX_GeographicBoundingBox>
> >               <BoundingBox ...>
> >               <Layer queryable="1">
> >
> <Name><![CDATA[USA_USGIN_3M_Lithostratigraphy]]></Name>
> >
> >
> > Stephen M Richard
> > Arizona Geological Survey
> > 416 W. congress #100
> > Tucson, AZ
> > AZGS: 520-770-3500
> > Office: 520-209-4127
> > FAX: 520-770-3505
>



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