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<TITLE>Re: [mapguide-dev] Metadata</TITLE>
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<DIV><FONT size=2><BR></FONT><FONT size=2><SPAN
style="FONT-SIZE: 10pt">
Hi all,</SPAN></FONT></DIV>
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<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt">Sorry for joining this
discussion so late, I just didn't get around to typing an answer about it
sooner. </SPAN><SPAN style="FONT-SIZE: 10pt">Let me share with all of you the
thinking behind why I chose the signatures for the stubs in the MapGuide
Web API the way they are.</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt">Metadata indeed is a tricky
topic - I totally agree with you Jason. There are several standards and most
of them are used by a variety of countries but none of them in all. In the US
we have this law that asks all government agencies to create FGDC metadata for
all data they create. As a result almost everyone in the US is mainly
concerned about native FGDC support. </SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt">If you go to Europe things are different, no one
cares about FGDC, they all want ISO ... Then there is the OGC standard
which is gaining popularity...</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt">So, no matter what standard we would choose to add to
the MapGuide API, it would be the wrong one ...</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt">The only thing they all have in common is that they
have a well defined XML schema representation. So if in the MapGuide API we
support a general XML schema storage for Metadata we support the most common
(if not all) of the standards out there and applications can use the schema
information in the XML content to decide what kind of metadata they are
dealing with.</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt">Then there was the question of whether we should
make metadata its own resource type or add a special API like I did. The
reason why I chose a new API ultimately is exactly your concern Jason.
Storing metadata as a xml blob may not be the right decision as it won't
scale and all resource data is stored as blob.</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt">Ideally metadata could be indexed in a server so it
can be searched quickly. Since we are using DbXML indexing XML files is really
easy. Also different MapGuide applications could implement the metadata
xml differently and still it would sclae up which is much harder if we were to
choose making it a resource type or hardcode a specific metadata standard.
</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt">So ... anyways ... that is where I am at with my
thinking ... what do you all think?</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN></FONT> </DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"></SPAN><SPAN
style="FONT-SIZE: 10pt">Cheers,</SPAN></FONT></DIV>
<DIV><FONT size=2><SPAN style="FONT-SIZE: 10pt"> </SPAN><SPAN
style="FONT-SIZE: 10pt"> Carsten</SPAN></FONT></DIV>
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<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>-----Original Message----- </FONT><BR><FONT size=2>From:
Jason Birch [<A
href="mailto:Jason.Birch@nanaimo.ca">mailto:Jason.Birch@nanaimo.ca</A>]
</FONT><BR><FONT size=2>Sent: Monday, September 18, 2006 3:37 PM
</FONT><BR><FONT size=2>To: dev@mapguide.osgeo.org </FONT><BR><FONT
size=2>Subject: RE: [mapguide-dev] Metadata </FONT></DIV>
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<P><FONT size=2>This comment from the header file: "The schema of
the Content is user </FONT><BR><FONT size=2>driven and not given. Most
people will use it for FGDC or ISO Metadata" </FONT><BR><FONT size=2>makes
me think that these unstructured entities will be used for storing
</FONT><BR><FONT size=2>fully structured GIS metadata. </FONT></P>
<P><FONT size=2>I can understand using freeform XML metadata for
file-based storage, so </FONT><BR><FONT size=2>that the data set is a
discrete unit. I am worried, however, that this </FONT><BR><FONT
size=2>will be seen as a good approach for a server-based metadata system,
and </FONT><BR><FONT size=2>I don't think that it is. </FONT></P>
<P><FONT size=2>Of course, because they are just free-form XML, I guess
there is nothing </FONT><BR><FONT size=2>stopping them from referring to
other resources for items like contacts, </FONT><BR><FONT size=2>rather
than storing the entire FGDC or TC211 document in a blob. </FONT></P>
<P><FONT size=2>Thinking about integration with Map 3D... If there is
going to be a </FONT><BR><FONT size=2>metadata editor (which would be
GREAT by the way) for creating external </FONT><BR><FONT size=2>XML files
for dwgs, shps, sdfs, etc, then these could be parsed on data
</FONT><BR><FONT size=2>upload. </FONT></P>
<P><FONT size=2>This item is really high up on my wishlist (I did add it
to the osgeo </FONT><BR><FONT size=2>wiki mapguide wishlist document), and
I really want to see it done right </FONT><BR><FONT size=2>the first time
rather than implementing something that is relatively </FONT><BR><FONT
size=2>easy to do but hard for end users to maintain. Getting
metadata buy-in </FONT><BR><FONT size=2>is hard enough without making it
difficult for users. </FONT></P>
<P><FONT size=2>Jason </FONT></P><BR>
<P><FONT size=2>-----Original Message----- </FONT><BR><FONT size=2>From:
Trevor Wekel [<A
href="mailto:trevor.wekel@autodesk.com">mailto:trevor.wekel@autodesk.com</A>]
</FONT><BR><FONT size=2>Sent: Monday, September 18, 2006 14:22
</FONT><BR><FONT size=2>To: dev@mapguide.osgeo.org </FONT><BR><FONT
size=2>Subject: RE: [mapguide-dev] Metadata </FONT></P>
<P><FONT size=2>Hi Paul, </FONT></P>
<P><FONT size=2>Yes. You are correct. The metadata system is
intended to store a </FONT><BR><FONT size=2>free-form XML blob for a
specific resource. Resource content documents </FONT><BR><FONT
size=2>are similar. Each resource does have a specific XML schema
but as far </FONT><BR><FONT size=2>as the ResourceService is concerned,
they are just valid XML blobs. </FONT></P>
<P><FONT size=2>Thanks, </FONT><BR><FONT size=2>Trevor </FONT></P>
<P><FONT size=2>-----Original Message----- </FONT><BR><FONT size=2>From:
Paul Spencer (External) </FONT><BR><FONT size=2>Sent: Monday, September
18, 2006 3:13 PM </FONT><BR><FONT size=2>To: dev@mapguide.osgeo.org
</FONT><BR><FONT size=2>Subject: Re: [mapguide-dev] Metadata </FONT></P>
<P><FONT size=2>Jason, </FONT></P>
<P><FONT size=2>I suspect that the metadata system they are putting in is
more in the </FONT><BR><FONT size=2>line of free-form storage system
associated with a resource rather than </FONT><BR><FONT size=2>a
structured metadata standard (FGDC?) which you seem to think this is.
</FONT><BR><FONT size=2>I could be wrong :) </FONT></P>
<P><FONT size=2>For instance, the description of the MapDefinition that
you enter in </FONT><BR><FONT size=2>Studio is stored in a metadata tag
inside the actual XML representation </FONT><BR><FONT size=2>of the
MapDefinition. </FONT></P>
<P><FONT size=2>I think you raise an excellent point, though. It
could be very </FONT><BR><FONT size=2>compelling to have a real metadata
capability inside MapGuide. </FONT></P>
<P><FONT size=2>Cheers </FONT></P>
<P><FONT size=2>Paul </FONT></P>
<P><FONT size=2>On 18-Sep-06, at 4:17 PM, Jason Birch wrote: </FONT></P>
<P><FONT size=2>> Hi all, </FONT><BR><FONT size=2>> </FONT><BR><FONT
size=2>> I am concerned that by just storing Metadata as an XML chunk
against </FONT><BR><FONT size=2>> resources, that it will be extremely
difficult to manage on an </FONT><BR><FONT size=2>> enterprise
level. I may just be getting worked up about something
</FONT><BR><FONT size=2>> that has already been considered but...
</FONT><BR><FONT size=2>> </FONT><BR><FONT size=2>> A good metadata
system should store at least organisation and contact </FONT><BR><FONT
size=2>> information independently, taking advantage of a relational
model and </FONT><BR><FONT size=2>> making maintenance easier.
Meta information stored against data sets </FONT><BR><FONT size=2>>
should be composited on the fly into the required metadata standard.
</FONT><BR><FONT size=2>> </FONT><BR><FONT size=2>> As well,
metadata should not be limited to the information stored </FONT><BR><FONT
size=2>> directly in MapGuide. It should be possible to store
metadata for </FONT><BR><FONT size=2>> external resources, including
those referred to in load procedures. </FONT><BR><FONT size=2>> The
metadata for the resultant data would then reference the source
</FONT><BR><FONT size=2>> they were derived from. </FONT><BR><FONT
size=2>> </FONT><BR><FONT size=2>> Hmm. On the flip side,
there should at least be the ability to parse </FONT><BR><FONT size=2>>
and load XML metadata in standard formats, such as generated by
</FONT><BR><FONT size=2>> ArcGIS. </FONT><BR><FONT size=2>>
</FONT><BR><FONT size=2>> Jason </FONT><BR><FONT size=2>>
</FONT><BR><FONT size=2>>
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</FONT><BR><FONT size=2>|Paul
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</FONT><BR><FONT size=2>|Applications & Software
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| </FONT><BR><FONT size=2>|DM Solutions Group
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