- Look at the "Content Standard for Digital Geospatial Metadata" for adequacy.
The
Content Standard for Digital Geospatial Metadata (CSDGM) is intended
to provide a formal structure for documentation of highly diverse
geospatial data products including but not limited to maps. As such
it incorporates some elements that are not likely to be used for
geologic maps (like Cloud_Cover), but most of the standard elements
will apply in a logical manner.
The proposed revision of the CSDGM includes formal recognition of
elements that are not part of the standard but are needed by
people in specific scientific disciplines to adequately represent
their data. One key quantity that is not well represented in the
CSDGM is geologic time, specifically geologic ages.
A possible extension was written to describe
specific additional elements that could be employed to represent
geologic ages. This need not be formalized as a profile of the
CSDGM but could be adopted after review by AASG and USGS by following
the procedures outlined in the proposed revision of the CSDGM.
Generally this means that the formal description of these extensions
will reside in a publically-accessible location on the network so
that those who are producing metadata can read and follow these as
guidelines. By employing this formal description in the available
metadata software a data manager can ensure that the geological ages
in the metadata are used according to this convention.
- Examine implementing metadata in a standard format for geologic maps.
Metadata software has come a long way since June of 1994. There
are now two standard formats for metadata files, one using SGML
(itself an international standard) and another using
indented text that can be converted to SGML using
USGS
software. That software can evaluate the metadata to
determine whether they conform to the CSDGM and can also generate
HTML, SGML, DIF, and indented text versions of the metadata for
use in other systems.
For those who have produced metadata using another schema (that
is, a different set of elements) custom software needs to be
written to convert those metadata records into the fields used
by CSDGM. The reason why you would want to do this is to make
your metadata available through the
National Geospatial Data
Clearinghouse, which is now operational and expanding in size
and scope. It will be difficult to convert metadata only if
the elements you have entered are more general than those of
the CSDGM. For example, if you include information about the
accuracy and completeness of the map data in a general description,
software won't generally be able to figure out which sentences
refer to completeness and which to accuracy (or of those, which
refer to attributes and which to positional information). But
if you broke the information down more finely than FGDC requires,
it will be easy to create a version of the metadata that fits
into the CSDGM. For example, if your metadata separates the
last names from the first names of the authors, these can be
easily combined to be put into the Originator field of the CSDGM.
- Establish guidelines as to what the metadata elements mean to a geologist.
The CSDGM is not specific to particular disciplines, and most of
the standard elements mean the same things to geologists as they
do to other -ologists and -ographers. Since consistency of use
across scientific disciplines is a key advantage of metadata,
geologists should consult the larger community of metadata
producers for assistance when the meaning of a standard element
is not clear to them. The best mechanisms for getting help are
to subscribe to NSDI-L (see
http://www.fgdc.gov/nsdil.html
for instructions)
and email the query to NSDI_L@fgdc.er.usgs.gov or to post the
question on the newsgroup comp.infosystems.gis. The NGMDB project
may want to establish a web site for discussion among geologists
of such issues. Users of the USGS software developed by Peter
Schweitzer can submit questions about that software to him
directly or to the users group, mp-users@geochange.er.usgs.gov. Under development is a guide to "Metadata in plain language", which is intended to provide users with definitions and guidance on metadata terminology.
- Determine a process for facilitating input from state geological surveys not represented at this meeting.
AASG and USGS should collaborate on developing web pages that
give resources through which people can learn about metadata.
- Format a specific set of fields that must be filled out for the NGMDB map catalog.
The catalog schema, as already defined by the NGMDB project, is acceptable; it is a brief subset of fields that map one-to-one
on CSDGM fields. NGMDB catalog records are considerably less
detailed than metadata records but the correspondence between
the two allows a degree of interoperability between clearinghouse
nodes and the NGMDB catalog, and allows metadata records to be
incorporated easily into the catalog.