Hi All,
ANZLIC - the Spatial Information Council for Australia and New Zealand are
developing an ISO 19115/19139 profile. The only change to ISO 19115 is that
the "fileIdentifer" is mandatory for implementation reasons and that the
"parentIdentifier" is a conditional "core" element for spatial datasets.
As you are probably aware the ISO 19139 does *not* fully implement ISO 19115.
Missing components are:
1. The ISO 19115 code lists,
2. The ISO 19115 conditional statements, and
3. The ability to have inheritance between metadata records. (Though this is
only informative and not a requirement.)
The ANZLIC Metadata Profile will have XML that meets all the above items.
The code lists will be in GML so that they can be registered according to ISO
19135 and can be referenced from the XML document instances.
The XSDs will be clones of the ISO 19139 XSDs and will include Schematron to
implement as many of the ISO 19115 conditional statements as possible.
(Currently there seems to be no reason why all the conditional statements
can't be implemented yet more investigation is needed.)
Inheritance can have two components:
1. Reuse of XML objects and
2. Inheritance of an xml element's content.
The former can be implemented using the Xlink component of the ISO 19139
XSDs. The ISO 19115 objects are generally the different classes that start
with a capital letter. EG. MD_Metadata, DQ_DataQuality, CI_ResponsibleParty,
etc. If these XML objects are stored and accessible from a service then they
can be included into a metadata record by the Xlink reference to the relevant
XML object of that service.
EG. The XML itself may look like (please forgive any incorrect syntax as
this is an example from the top of my head):
<?xml encoding="utf-8" language="eng">
<MD_Metadata>
<fileIdentifier><CharacterString>uuid</CharacterString></fileIdentifier>
...
<contact xmlns:ns1="http://www.w3.org/1999/xlink" ns1:type="simple"
ns1:href="http://geonetwork.org/catalogueService#element(//CI_ResponsiblePart
y[./name[@codeSpace=fileIdentifier='UUID'])">
</contact>
...
</MD_Metadata>
This will, on presentation, put into the CI_ResponsibleParty of the "contact"
element the information available from the href.
Real "inheritance" will be available in the XSDs by adding an optional
attribute called "source" to each appropriate element. It is intended that
the "source" attribute will be a URL (including XPATH) to any XML element
resource.
Implementation can use the "source" attribute as follows:
If a metadata element "inherits" from a parent metadata record then the
child's parentIdentifier content will be the same as the parent's
fileIdentifier content. The Metadata Entry Tool (MET) can then set the
"source" attribute of each element to point to the Catalogue Service for that
metadata record and the full XPATH to the parent element which the content is
being inherited into the child metadata record.
If extra elements are added to the child metadata record using the MET, then
these elements do not get the "source" attribute. If the inherited elements
are edited using the MET then the "source" attribute for these edited
elements are removed.
The content of the elements does not necessarily have to be derived from
other metadata records. It can be derived from the data itself because the
URL can point to any data service. This is very useful for the lower level
metadata.
For example, the metadata for a "feature" can inherit as much as possible
from the parent "featureType" metadata. The content of other elements can be
inherited from the data itself. This will help automate the generation of
lower level metadata.
I believe that this implementation will satisfy all the ISO 19115
requirements that ISO 19139 missed. It could be adopted by the GeoNetwork
MET to properly implement ISO 19115. What do you developers think? Are you
interested in making GeoNetwork much more ISO 19115/19139 compliant? If so I
will send an email to this list when the XML for the ANZLIC Metadata Profile
is available.
Thanks.
John Hockaday
Geoscience Australia
GPO Box 378
Canberra ACT 2601
(02) 6249 9735
http://www.ga.gov.au/
john.hockaday\@ga.gov.au