[mapguide-dev] Metadata

Jason Birch Jason.Birch at nanaimo.ca
Mon Sep 18 17:37:26 EDT 2006


This comment from the header file:  "The schema of the Content is user
driven and not given. Most people will use it for FGDC or ISO Metadata"
makes me think that these unstructured entities will be used for storing
fully structured GIS metadata.

I can understand using freeform XML metadata for file-based storage, so
that the data set is a discrete unit.  I am worried, however, that this
will be seen as a good approach for a server-based metadata system, and
I don't think that it is.

Of course, because they are just free-form XML, I guess there is nothing
stopping them from referring to other resources for items like contacts,
rather than storing the entire FGDC or TC211 document in a blob.

Thinking about integration with Map 3D... If there is going to be a
metadata editor (which would be GREAT by the way) for creating external
XML files for dwgs, shps, sdfs, etc, then these could be parsed on data
upload.

This item is really high up on my wishlist (I did add it to the osgeo
wiki mapguide wishlist document), and I really want to see it done right
the first time rather than implementing something that is relatively
easy to do but hard for end users to maintain.  Getting metadata buy-in
is hard enough without making it difficult for users.

Jason


-----Original Message-----
From: Trevor Wekel [mailto:trevor.wekel at autodesk.com] 
Sent: Monday, September 18, 2006 14:22
To: dev at mapguide.osgeo.org
Subject: RE: [mapguide-dev] Metadata

Hi Paul,

Yes.  You are correct.  The metadata system is intended to store a
free-form XML blob for a specific resource.  Resource content documents
are similar.  Each resource does have a specific XML schema but as far
as the ResourceService is concerned, they are just valid XML blobs.

Thanks,
Trevor 

-----Original Message-----
From: Paul Spencer (External)
Sent: Monday, September 18, 2006 3:13 PM
To: dev at mapguide.osgeo.org
Subject: Re: [mapguide-dev] Metadata

Jason,

I suspect that the metadata system they are putting in is more in the
line of free-form storage system associated with a resource rather than
a structured metadata standard (FGDC?) which you seem to think this is.
I could be wrong :)

For instance, the description of the MapDefinition that you enter in
Studio is stored in a metadata tag inside the actual XML representation
of the MapDefinition.

I think you raise an excellent point, though.  It could be very
compelling to have a real metadata capability inside MapGuide.

Cheers

Paul

On 18-Sep-06, at 4:17 PM, Jason Birch wrote:

> Hi all,
>
> I am concerned that by just storing Metadata as an XML chunk against 
> resources, that it will be extremely difficult to manage on an 
> enterprise level.  I may just be getting worked up about something 
> that has already been considered but...
>
> A good metadata system should store at least organisation and contact 
> information independently, taking advantage of a relational model and 
> making maintenance easier.  Meta information stored against data sets 
> should be composited on the fly into the required metadata standard.
>
> As well, metadata should not be limited to the information stored 
> directly in MapGuide.  It should be possible to store metadata for 
> external resources, including those referred to in load procedures.
> The metadata for the resultant data would then reference the source 
> they were derived from.
>
> Hmm.  On the flip side, there should at least be the ability to parse 
> and load XML metadata in standard formats, such as generated by 
> ArcGIS.
>
> Jason
>
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+-----------------------------------------------------------------+
|Paul Spencer                           pspencer at dmsolutions.ca   |
+-----------------------------------------------------------------+
|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|
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