[Freegis-list] Re: Freegis-list digest, Vol 1 #337 - 4 msgs

[Alfred de Jager]

Dear Alexander,

Regarding your geodatabase metadata storage and fgdc metadata collectors.
Please take care before using these tools. They are merely conceived to collect in one moment metadata not to
update or relate between them. In order to do the latter you better throw away all those flat-file models and start
over with a 'normalized' model containing only the essentials.
Hint, try to update the phone number of your 'contact person' using ArcGIS

The problem of the whole GI metadata hype is that we do not apply the normal IT rules of data normalization
(no redundancy) and essentialization (store the minimum and derive what is derivable).
GI Metadata is still an enduser wish list and in any implementation I have seen thus far the whole thing is mixed
and end user perspective driven. Apperently nowbody cares about the managebility of these data!
I think we now know what the end user wants! We have around 3 official committees writing down cryptic definitions
for field names like 'title', 'author' etc.
What we now need to do is to define which information is derivable and which is not. From what is not derivable you
need to check if it is essential (is my faxnumber essential to know at the level of metadata?) if not skip it.

The remaining information needs to be normalized and stored in a database out of which you generate (perhaps xml)
information sheets. One does not store XML sheets!!!!!!!
Normalization means that every repeated piece of information (eg a contact person) results in a separated relatable
table. Such a database does not exist in a generic way since the essentialization must result for any organization
in a slightly different model.
To exchange information between organizations both organizations must not only agree on a physical protocol like
Z39 but more on the identification of their objects (contact persons, organizations, placenames, keywords,
reference systems and the whole bunch).

Conclusion.
Metadata systems when seriously applied do not come out of the box, you ought to develop yourself a model and if
you what to exchange metadata with organizations outside your model you should first agree on object identifiers
before even bothering on exchanging.

My Hints:
Most databases contain a 'comment' field for any object, unstructured metadata (definition of what it is, what
units are used) can be stored best in there, close to the data.
For organisational information you just use the contact administration of e.g. your browser in which an email
address can be an unique identifier. Most browsers allow in various modes to 'share' that information and make it
searchable. Note that browser contact information is not normalized. Thus if your organisation is large you better
buy a contact administration package.
Most GI metadata is derivable from the dataset themselves and using simple batch programs you should be able to
make that searchable as well. Geodatabase does the latter, partly, and if convenient for you, you can use that.
In Oracle (and other databases) the whole database structure is stored in the database dictionary and thus using
Geodatabase on top of Oracle is a little bit double (understatement).

What then remains is the creation of one table containing.... two fields:

"contactperson email", "physical dataset location"

Just imagine the simplicity.

Caio
--
Drs. Alfred de Jager
Geographer, GIS and Database Consultant

Portal for European Landscape Research
http://www.aris.sai.jrc.it/en/search-tools


freegis-list-request at intevation.de wrote:

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> Today's Topics:
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>    1. Re: Clearinghouse (Alexander Pucher)
>    2. Re: Clearinghouse (Bernhard Reiter)
>    3. Re: Clearinghouse (Andrew Hallam)
>    4. JaGo and GeoTools: Any comparative remarks? (Stefan F. Keller)
>
> --__--__--
>
> Message: 1
> Date: Mon, 01 Apr 2002 12:49:18 +0200
> From: Alexander Pucher <pucher at atlas.gis.univie.ac.at>
> Cc: Freegis-list at intevation.de
> Subject: Re: [Freegis-list] Clearinghouse
>
> Wow, a lot of information coming in the last days. Thanks you all so
> far-John, Jan and Felipe.
>
> My personal intention (that's why I posted my question) is simple. We
> have a lot of geodata in our dept., stored in several ArcGIS personal
> geodatabases. All I want to do is to set up a web-based  intranet search
> engine, so that dept. members can search the available data. In a first
> step, it is not needed that users can actually download the datafiles-a
> metadata result list of the queried data would be enough. I think, this
> is not really a clearinghouse, for it would only have one peer.
>
> Changes are good that some of my colleagues will try to set up a
> ESRI-based system, but my intention is to do it with free software.
>
> I had a look at the Z39.50 protocol stuff from FGDC and played around a
> bit with the Isite software package. Looks good, but still some
> questions remain like "how to get all the metadata out of ArcGIS in
> batchmode" etc.
>
> I will have a look at your URLs (esp. the PHP item) and will come back
> as soon as I've been through them.
>
> Best wishes,
> alex
>
> Felipe Nievinski wrote:
>
> >Hi.
> >
> >On Mon, 01 Apr 2002, John Reid wrote:
> >
> >>I'm currently looking at setting up a demo dataset using freely
> >>available datasets for my local area, concentrating initially on storage
> >>of data catalogues and metadata.
> >>
> >
> >John,
> >I just read your message. The message below is in response to Alexander's message.
> >The idea of the addition to the SDI Cookbook is great. I'll get back to you asap.
> >
> >
> >On Tue, Mar 26, 2002, Alexander Pucher wrote:
> >
> >>I'm recently planning to set up an geodata clearinghouse using free
> >>software. Right now, all data is stored in an ArcGIS personal
> >>geodatabase. I've searched the web and found some stuff from the FGDC
> >>(mainly the Isite package).
> >>
> >
> >By clearinghouse I understand a decentralized system of servers
> >full of metadata in a networked environment, used for resource
> >discovery.
> >
> >The Z39.50 protocol is widely used for communication between
> >computers in a clearinghouse. Isite is a package of (free
> >software) programs for distributed searching. It contains a
> >Z39.50 server implementation, besides other things.
> >
> >By using Isite you can:
> >- index a file collection, each file being a metadata record,
> >- search locally this database,
> >- receive queries via Z39.50.
> >
> >If you just want to create and add a server peer to an existing
> >clearinghouse (for example, registry.gsdi.org) this is almost
> >all you'll need to do. You can then notify the clearinghouse
> >maintainer that your server is ready to be accessed, and
> >perform queries on local or remote Z39.50 servers using a
> >Z39.50 client or through an already available http to Z39.50
> >gateway.
> >
> >To manage your metadata file collection (create, update and
> >delete records), do it by hand offline, or build a web-based
> >system using your prefered language. There is available (see
> >URL below) a set of very elucidative Perl scripts which makes
> >a metadata entry system.
> >Any modification to your metadata-base you'll have to re-index
> >it and restart the Z server.
> >
> >If you also want to build your own http to z39.50 gateway, be
> >prepared to dig deep. As far as I can tell you, the Isite zcon
> >defines the presentation of the search results (the way it
> >formats Z39.50 responses into HTML) in its source code, so
> >you'll have to hack its internals just to add your
> >university logo to the results page, for example.
> >Maybe the PHPYAZ (again, see URL below), a Z39.50 client
> >for PHP, can do a better job.
> >
> >If you want to serve the actual data online, provide links for
> >it in the metadata records (the metadata standards usually
> >define linkage fields to provide this information). Look at a (free)
> >Web Map Service server or a Web Feature Server if you want
> >to provide dynamic content rather than just static files.
> >
> >Just some ideas.
> >Commentaries are welcomed.
> >
> >The URLs:
> >- Isite 2.05 - General Instructions
> >  http://www.awcubed.com/Isite/FGDC-README.html
> >- Web-based FGDC Metadata Entry System
> >  http://130.11.52.178/metaover.html
> >- PHPYAZ
> >  http://www.indexdata.dk/phpyaz/
> >- Spatial Data Infrastrucures Implementation Guide
> >  Chapter Four: Geospatial Data Catalog -- Making data discoverable
> >  http://www.gsdi.org/pubs/cookbook/cookbook0515.pdf
> >
> >regards,
> >Felipe N.
> >
> >
> >_______________________________________________
> >Freegis-list mailing list
> >Freegis-list at intevation.de
> >https://intevation.de/mailman/listinfo/freegis-list
> >
> >
>
> --
> ________________________________________________________
>
> Institut fuer Geographie und Regionalforschung
> Universitaet Wien
> Kartografie und Geoinformation
>
> Departement of Geography and Regional Research
> University of Vienna
> Cartography and GIS
>
> Universitaetstr. 7, A-1010 Wien, AUSTRIA
>
> Tel: (+43 1) 4277 48644
> Fax: (+43 1) 4277 48649
> E-mail: pucher at atlas.gis.univie.ac.at
>
> FTP: ftp://ftp.gis.univie.ac.at
> WWW: http://www.gis.univie.ac.at/karto
> ________________________________________________________
>
> "The chance of the bread falling with the butter side down is directly proportional to the value of the carpet"
>
> --Jennings' Corollary to the Law of Selective Gravity
>
>
> --__--__--
>
> Message: 2
> Date: Mon, 1 Apr 2002 13:47:27 +0200
> From: Bernhard Reiter <bernhard at intevation.de>
> To: Freegis-list at intevation.de
> Subject: Re: [Freegis-list] Clearinghouse
>
> --zq44+AAfm4giZpo5
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>
> On Mon, Apr 01, 2002 at 12:49:18PM +0200, Alexander Pucher wrote:
> > My personal intention (that's why I posted my question) is simple. We=20
> > have a lot of geodata in our dept., stored in several ArcGIS personal=20
> > geodatabases. All I want to do is to set up a web-based  intranet search=
> =20
> > engine, so that dept. members can search the available data.=20
>
> So me this sound like the key technocal point for you will be to=20
> find a good way to access the data in the databases. Let me
> elaborate on this a bit.
>
> Personally I do not have much experience with what to expect when
> you write "ArcGIS personal geodatabase". I also did not find good
> information about the underlying technology searching the web for a
> couple of minutes. This is something you have to find out.
>
> Let's assume the geo and attribute data is in a DBMS based on MS Access.
> As long as the data is in there, you cannot manipulate it easily
> from a complete Free Software setting. Thus you probably want to
> extract the data in order gain back control over it.
>
> I'm not aware of software that can work directly on the files of MS Access,=
> =20
> but I did not look for this kind of software so far.
> Assuming you are stuck with going over ms access interfaces
> running ms windows you probably can utilise the com interface.
> Python windows will enable you to do this and write a script you=20
> might run non-interactively. Certainly there are other ways.
>
> Once you have access to the data in the database you can set up
> periodical scripts to collect the data you want and transfer them in your=
> =20
> simple database (e.g. text file based, postgresql or mysql).
> Adding a web and search interface to such a database is an easy
> exercise you find many tutorials for utilising Free Software (e.g.
> zope, php3, Quixote).
>
> > In a first=20
> > step, it is not needed that users can actually download the datafiles-a=
> =20
> > metadata result list of the queried data would be enough. I think, this=
> =20
> > is not really a clearinghouse, for it would only have one peer.
> >=20
> > Changes are good that some of my colleagues will try to set up a=20
> > ESRI-based system, but my intention is to do it with free software.
>
> Please report back what you were able to do and what you've found out.
>
> --=20
> Professional Service around Free Software                (intevation.net) =
> =20
>
> If freegis is useful for you, consider paying for the service:
>         http://freegis.org/about-paying.en.html
>
> --zq44+AAfm4giZpo5
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> --__--__--
>
> Message: 3
> Date: Tue, 02 Apr 2002 14:39:48 +1000
> From: Andrew Hallam <ahallam at digitalearth.com.au>
> Reply-To: Andrew Hallam <ahallam at digitalearth.com.au>
> To: Freegis-list at intevation.de
> Subject: Re: [Freegis-list] Clearinghouse
>
> --On Monday, April 01, 2002 13:47 +0200 Bernhard Reiter
> <bernhard at intevation.de> wrote:
>
> > I'm not aware of software that can work directly on the files of MS
> > Access,  but I did not look for this kind of software so far.
>
> Quick think, possible options:
>
> - Python with Win32 extensions can use ADO to connect to any Access file
> and access the tables.
> - PHP's COM module provides similar tools.
> - See also ActivePerl and ActivePython.
>
> All the above require writing code so it would be easier to use Access to
> export the data.
>
> - There is an extension to pgAccess II which contains a GUI based Access to
> PostgreSQL wizard (haven't used it myself).
>
> Regards
> Andrew Hallam
>
> Digital Earth Pty Ltd
> http://www.digitalearth.com.au
>
> --__--__--
>
> Message: 4
> Date: Tue, 02 Apr 2002 07:51:59 +0200
> From: "Stefan F. Keller" <sfkeller at hsr.ch>
> Reply-To: "Stefan F. Keller" <sfkeller at hsr.ch>
> Organization: HSR Hochschule fuer Technik Rapperswil - FH Ostschweiz
> To: freegis-list at intevation.de
> Subject: [Freegis-list] JaGo and GeoTools: Any comparative remarks?
>
> Dear all
>
> I am interested in issueing a diploma thesis
> which should test - among other items - the capabilities
> of available open source geodata viewers (primarily as
> stand-alone clients applications). The primary goal is
> to use them for simple web mapping purposes of a universal
> vector geodata language (INTERLIS - the GeoLanguage; sort of
> superset standard of UML/GML from Switzerland, www.interlis.ch).
>
> I've found JaGo and GeoTools so far.
> Now, I would like to ask you the following:
>
> - has anybody experience using one of these or both?
> - does anybody know other relevant projects?
>
> Regards
> -- Stefan Keller
>
> P.S. My first impressions:
> - JaGo seems to me appealing but there is only one upload
>   compared to GeoTools.
> - GeoTools is more active but I could not evaluate its
>   architecture yet.
> ___________________________________________________________________
> Prof. Stefan F. Keller, Dozent fuer Informatik
> Center für integrierte Geo-Informationssysteme (int>e>gis)
> am Institut ITA-HSR der Hochschule fuer Technik Rapperswil (HSR)
> CH-8640 Rapperswil, Tel. 055 222 47 46, Fax 055 222 44 00
> mailto:sfkeller at hsr.ch, http://www.hsr.ch und http://integis.ch
> ___________________________________________________________________
> HSR, der schönste Campus der Schweiz... siehe http://netcam.hsr.ch/
>
> --__--__--
>
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