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ASDI-L Mailing List Archive

From: David Crossley ([email protected])
Date: Wed Jun 18 2003 - 08:04:26 EST


Bleys, Evert - BRS wrote:
...
> As you may be aware we have been playing with ISO 19115
> (but that is of no major concern)
> As a result we approve of any use of the
> on-line resource options that are compatable with ISO
>
> What is also needed (and I am happy to try to coordinate)
> is the dictionary of terms that enumerate the fields
> The need to define the elements within the DTD
> These elements are
> TransOnLine (Container Element O N -)
> Linkage (Simple Element M 1 FreeText )
> Protocol (Simple Element O 1 FreeText )
> ApplicationProfile (Simple Element O 1 FreeText )
> Name (Simple Element O 1 FreeText )
> Description (Simple Element O 1 FreeText )
> Function (Simple Element O 1 Text from List)
> The optional obligation is a hassle
> I think most if not all should be mandatory
> (if you are going to play - then get real)

Yes, most should be mandatory within TransOnLine. However, we could
just have guidelines to say: if you want to link to something, then here
is how to. The key is to have very clear definitions of these fields and
various real-life examples of their use.

For the demo, the only two that we actually used are Linkage and
ApplicationProfile. At the bottom of the interface page
(http://www.indexgeo.net/zap/getmap/) there is a link to explain how
we implemented this capability.

> The ISO definitions are not overly helpful
> I suggest that
> Linkage
> (ISO defines as "location for on-line access using URL or similar")
> be the URL eg if wms then it is the address of the service

Yes. Since each of our example metadata records describe individual
layers, we link directly to the layer in our WMS service.

> Protocol
> (ISO defines as "Connection protocols
> to be used")
> be something like a list of mechanisms
> e.g. FTP, WMS, WFS (need help here)

Not sure what this field is meant for. It does look like
it could be useful, given well-constrained content.

> ApplicationProfile
> (ISO defines as "Name of Application
> profile that can be used with the
> on-line Resource")
> be something like a list of formats
> e.g. OGC (need help here)

Here are two examples of what we are using in that field:
 ogc:WMS-1.1.0-http-get-map
 ogc:WMS-1.1.0-http-get-capabilities
I think that this is dangerous - too much information in one field.
It would be better to have separate metadata fields.

For our ASDD demo, we search in this field for the term "WMS" and
the term "get-map". As you can see, we are using it as a catch-all
... not good information science, but fine for a demo.

> Name
> (ISO defines as "Name specified
> for the on-line resource within
> the capability of the Protocol")
> be the name of the layer or file
> (Note that in the case of
> FTP this would be redundant,
> but for WMS critical)

We have this a long text name for the resource. The actual layer
name is embedded in the Linkage URL for WMS. Why do you say that
this field is critical?

> Description
> (ISO defines as a "Text description
> of what the on-line resource is/does")
> (Note - this would be useful if/when
> things go wrong)

Yes, useful.

> Function
> (ISO has defined as one of:
> download; information; offlineAccess; order; search
> These are of little real value in this context.

I agree that the authority list is way too limiting. With better
code list values, this field might be useful.

--David


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