[Freegis-list] Re: metadata recommendations (continued)

[Stefan F. Keller]

Sorry again: 
I 'd like to answer to Alfred the following:

o Regarding simplicity in Metadata: At MEGRIN (years ago for
LaClef project) and on the bi-annual Swiss GIS conference two
years ago I proposed a so-called "Simple Metadata Model" (even
here, I have to dig out the english paper which included
UML-/INTERLIS- and XML Schemas).

o Regarding "normalization" Alfred mentioned: I would even
suggest really object-oriented data schemas (not good old
relational) which can be extended at a national level or
locally) . Thus one should rather speak of "well- designed,
robust or change resistant schemas". How these are mapped to
existing relational data base can be delegated to the computer
specialists. There are tools for this (like the forthcoming Open
Source UML/INTERLIS-Editor at http://www.eisenhutinformatik.ch).

o Regarding exchange of data (including geodata and metadata):
You mention that there must be an agreement on Object
Identifiers. This is again right. Alt least there must be
common "user defined keys" (besides the common geo-reference
system). When I mention INTERLIS also here, it's because we got
an agreement two years ago on generic OID-generation between 
cadastral surveying in Germany (ADV) and Switzerland
(http://www.kogis.ch)! We called it sometimes SOID ("Simple
Object Identifier" sic!) and it's published and available
as a service at http://www.interlis.ch.

o As long as there is no software around for ISO Metadata
Core, what I propose for metadata managment NOW are the
following basic documents (all with the same root name):

1. Object Catalog: A simple textual/tabular document which 
   describes the geodata objects in plain language; 
   => a HTML-file (perhaps with style sheets)
   can be generated, if software is available
   (like the above mentioned UML/INTERLIS-Editor).

2. Main Geodata Schema (textual, computer readable notation) : 
   A precise model of the geodata; the *key document* 
   of all geodata and geo-services including classes, attributes,
   data types, units, reference system; 
   => an UNICODE (ASCII)-text in INTERLIS.

3. Other Geodata Schemas (graphic notation) : automatically (!) 
   derived from (2.) using the freely available INTERLIS compiler: 
   => 3a. An UML class diagram in JPEG 
      and 3b. an XML Schema (ASCII).

4. Metadata : A textual/tabular document according to the 
   "Simple Metadata Model" (as defined above in INTERLIS and 
   derived XML-Schema); mention additional product (price, 
   quality, category, spatial extension derived from geodata 
   and supplier information  (contact email)... and links 
   together all the (partially generated) files from above.
   => A HTML-file (with style sheets) which is generated
   using XSLT (this file should be exported later on from a 
   Metadata/Catalogueing Software).

If these documents are published on web server they are 
searchable almost for free if a search functions is 
available on the web server software.

As somebody mentioned before: Why not consider uploading its
metadata to a up and running remote "Clearinghouse or 
Geo Portal" acting as an application service; as long as 
this is not proprietary, or able to archive its contents 
in XML (sorry again these formats) at any time...?

A last recommendation when you model your metadata schema on
your own or consider buying/using an available software: just
keep your eyes on the ISO 19115 Metadata Core Schema if you 
want to update share your metadata for a longer time.

Regards
-- Stefan F. Keller