TABLE
OF CONTENTS
Maine Office of GIS FGDC Initiatives
Technical Support for FGDC Metadata Development in Maine
Maine
GIS has adopted the Federal Geographic Data Committee (FGDC), “Content Standard
for Digital Geospatial Metadata” (CSDGM), as a documentation or
"metadata" standard for geospatial data. Maine GIS data documented
with FGDC metadata is published through the Maine GIS Internet Data Catalog and
is made available to the national clearinghouse nodes of the National Spatial
Data Infrastructure (NSDI) and the US Geological Survey National Map. Data
developers are responsible for providing documentation in FGDC format for each
digital map added to the Maine GIS database. The metadata must be stored and
maintained by the contributor or agency responsible for developing and
maintaining the data.
Metadata
is "data about data". Like a style guide, the FGDC CSDGM defines what
information belongs in a metadata record and the format in which the
information is presented. The goals and objectives of the Maine GIS FGDC
compliant documentation can be summarized as follows:
o to provide a history of each Maine GIS geospatial data set
with standardized information on content,
location, purpose,
accuracy, condition,
quality, collection, development
processes, scale,
projection, feature attributes, and
other characteristics
of geospatial data necessary to determine
the utility of a map
for a specific purpose
o to protect Maine’s investment in geospatial data, by
minimizing
the risk of data loss
and the re-creation of existing
data, through
systematized documentation of geospatial information
o to promote data sharing by providing information about Maine
GIS
data holdings to
external catalogues, clearinghouses, and brokerages
and by providing
information on the processing and interpretation
of spatial data
received through a transfer from an external source
Federal
Geographic Data Committee (FGDC) metadata answers the who, what, where, when,
how and why questions of geospatial data. The data structure and elements
defined for FGDC metadata are described fully in the “Content Standard for
Digital Geospatial Metadata” (CSDGM). A CSDGM Workbook provides specific help
and examples for the completion of each FGDC element and is available at http://www.fgdc.gov/metadata/meta_workbook.html.
Questions
always arise about “How much of this information is required?” or “Can’t the
process be simplified for our purposes?”. The best responses to these questions
and others can be found at
http://geology.usgs.gov/tools/metadata/tools/doc/faq.html. This site
“Frequently asked questions on FGDC metadata” contains much good discussion on
the topic. To quote a few important points:
·
“Document at a level that preserves
the value of the data within your organization. Consider how much you would
like to know about your data sets if
one of your senior GIS operators left suddenly.” (FAQ, p.5)
·
“Don’t invent your own
standard. There already is one. Try to stay within its constructs. Subtle
changes from the CSDGM...can be costly in the long run-you may not be able to
use standard metadata tools and your metadata may not be exchangeable.”(FAQ,
p.4)
·
“…The costs and value of
metadata, to both immediate and longer-term operations, should be evaluated at
the start. Judgment also is needed on deciding what information about source
materials should be retained. Documenting existing or “legacy” data can be
daunting. Details are long forgotten and costs can be high. These concerns are
valid, but care should be taken to avoid allowing issues related to legacy data
to unduly influence the documentation of new data.”(CSDGMWkbk, p.8)
The Federal Geographic Data Committee (FGDC), Content Standard
for Digital Geospatial Metadata (CSDGM) organizes a metadata record into seven
main sections:
o Identification
Information,
o Data Quality
Information,
o Spatial Data
Organization Information,
o Spatial Reference
Information,
o Entity and
Attribute Information,
o Distribution
Information,
o Metadata
Reference Information.
These sections are constructed from both simple and compound
data elements. A simple element is a stand-alone unit of metadata. Compound
elements may consist of a group of related simple elements and/or compound
elements. A type of compound element exists in the elements “Citation
Information” and/or “Contact Information”. These elements record a set of
information related to specific data authors, publishers, process contacts,
sources, and metadata contacts, for reuse in various sections of a metadata
document and throughout a metadata collection.
The following questions provide examples of the type of
information required to complete the content development of the seven sections
of Federal Geographic Data Committee (FGDC) metadata:
Identification Information
What is the name of the dataset?
What is the subject or theme of the information included?
What is the scale of the dataset?
What are the attributes of the dataset?
Where is the geographic location of the dataset?
Who developed the dataset?
Who provided the source material for the dataset?
Who will publish the dataset?
When were the features of the dataset identified?
How are the features of the dataset depicted?
Why was the data set created?
Are there restrictions on accessing or using the data?
Are external files available that are related to the dataset?
Data Quality Information
How reliable are the data?
What are its limitations or inconsistencies?
What is the positional and attribute accuracy?
Is the dataset complete?
Were the consistency and content of the data verified?
Where can the sources of the data be located?
What processes were applied to these sources and by whom?
Spatial Data Organization
What spatial data model was used to encode the spatial data?
How many and what kind of spatial objects are included in the
dataset?
Are methods other than coordinates, such as street addresses
used to encode locations?
Spatial Reference
Are coordinate locations encoded using longitude and latitude?
What map projections is used?
What horizontal datum and/or vertical datum are used?
What parameters should be used to convert the data to another
coordinate system?
Entity and Attribute Information
What geographic information (roads, houses, elevation,
temperature, etc.) is described?
How is this information coded?
What do the codes mean?
What source was used for defining the attributes or codes, i.e.
Cowardin classification?
Distribution
From whom can the data be obtained?
What formats are available?
What media are available?
Are the data available online?
What is the price of the data?
Metadata Reference
When were the metadata compiled, and by whom?
When was the metadata record created?
Who is the responsible party?
When were the metadata last updated?
Two FGDC
compliant metadata tools are in common use among Maine GIS users: ESRI’s ArcGIS
ArcCatalog metadata tool suite and SMMS Spatial Metadata Management System from
Intergraph. While all FGDC metadata has a standard exchangeable format, the
usability and limitations of various tools for metadata creation affect the way
the metadata, will be stored and the structure built-into a metadata tool
affects the subsequent use of the metadata. In considering the selection of a
metadata tool it is important to evaluate other organizational needs such as
metadata update, management, publication, coordination and data sharing.
ArcCatalog
metadata tools are freely available to anyone using ArcGIS software, therefore
this is the tool of choice for many Maine GIS users. ArcCatalog metadata tools
use a file based system and store metadata as an embedded .xml file within the
geospatial data format, i.e. geodatabase, shapefile. Metadata can be viewed,
created, edited, imported and exported from ArcCatalog in a variety of formats. In addition to the FGDC “classic”
format, ArcCatalog metadata can be viewed in a variety of style sheets all
built on the native xml format. The file based system lends itself well to browsing
associated metadata within ESRI software. The system is less easily suited for
handling enterprise wide metadata tasks like the standardization of contact,
citation, keyword information. Among the exportable FGDC compliant formats, the
CSDGM TXT format is most easily portable to other FGDC compliant tools.
The Maine
Office of GIS (MEGIS), in cooperation with Maine's GIS Executive Council and
the GIS Technical Group, has purchased two licenses of Spatial Metadata
Management System (SMMS) software for metadata creation and management. SMMS is a platform independent, database supported tool from
Intergraph. SMMS provides database capabilities to search evaluate, locate and
load, catalog, and synchronize data holdings. The tool is used at MEGIS to create,
update, and maintain an entire catalog of Maine GIS metadata from data
contributed to the Maine GIS database by Maine GIS users. FGDC compliant ASCII
text files imported into SMMS from a variety of sources are stored by MEGIS in
an Oracle database at the Office of Information Technology. The Maine GIS
Internet Data Catalog provides data selection, description and query directly
from this database. In addition FGDC Encoded ASCII text files and html format
files are exported from the database to refresh the Maine GIS MEGIS.<SDE>
and the Maine GIS server directory at /home11/crypt83/metadata/fgdc. A
directory of metadata files served to the Internet makes all Maine GIS data
available to a variety of national clearinghouse sites, including the USGS National
Map and the FGDC NSDI clearinghouse.
A number of other commercial software products, as well as some free
metadata tools, are available for the development of FGDC compliant metadata.
Among these are the U.S. Army Corps of Engineers’ Corpsmet95, Metamaker from
the Upper Midwest Environmental Sciences Center (Biological Resources Division,
U.S. Geological Survey), and the metadata toolkit, utilities available from
USGS. Others are packaged with GIS software. For further information and
evaluation of metadata tools see http://www.fgdc.gov/metadata/metatool.html .
Technical
Support for FGDC Metadata Development in Maine
The
Maine Office of GIS (MEGIS) provides technical support to state agencies and
the public for content development of FGDC metadata and information on FGDC
compliant software for metadata development is available through the Maine
Office of GIS, Data Center, Technical Support phone line at (207) 287-6144.
Lists
of organizations, acronyms, sources, citations, and source abbreviations, and
keywords actively used in Maine GIS are available. These may be useful in the
completion of the following FGDC sections and elements: Identification
Information (Citation Information, Point of Contact), Keywords (Theme, Place,
Stratum), Data Quality Information (Lineage, Source Citation, Source Citation
Abbreviation, Process Contact), Entity and Attribute Information (Enumerated
Domain Value Definition Source, Code set Source), Distribution Information
(Distributor, Contact Information), Metadata Reference Information (Metadata
Contact).
Contacts
& Acronyms
Sources & Abbreviations
Thesauri (XML Documents)
Please report list errors to
the Maine Office of Geographic Information Systems at (207)287-6144, or through
the feedback form available at <http://apollo.ogis.state.me.us>.
Federal
Geographic Data Committee (FGDC) metadata is the required documentation of all
geospatial data products produced through partnerships, grants or contracts
with federal agencies. Federal agencies collecting or producing geospatial
data, either directly or indirectly (e.g. through grants, partnerships, or
contracts with other entities), are required to ensure, prior to obligating
funds for such activities, that data will be collected in a manner that meets
all relevant standards adopted through the FGDC process. (Executive Order
12906, published in the April 13, 1994, edition of the Federal Register, Volume
59, Number 71, pp. 17671-17674. COORDINATING GEOGRAPHIC DATA ACQUISITION AND
ACCESS: THE NATIONAL SPATIAL DATA INFRASTRUCTURE)
FGDC
metadata documents are also the basic components of the National Geospatial
Data Clearinghouse, and FGDC compliant metadata for Maine GIS geospatial data
can be made available to clearinghouse nodes nationwide. The National
Geospatial Data Clearinghouse is a distributed online catalog of digital
spatial data, part of the National Spatial Data Infrastructure (NSDI)
(Executive Order 12906). NSDI goals are to reduce duplication of effort among
agencies, improve quality and reduce costs related to geographic information,
to make geographic data more accessible to the public, to increase the benefits
of using available data, and to establish key partnerships with states,
counties, cities, tribal nations, academia and the private sector to increase
data availability.
For more information on Federal Geographic Data Committee (FGDC)
metadata, the National Spatial Data Infrastructure (NSDI) and the National
Geospatial Data Clearinghouse, the following organizations and links may be
helpful:
http://fgdc.er.usgs.gov/metadata/metatool.html
Evaluation of available
metadata tools including one for Arc View. Some of these are free. Each has its
limits, but all contain the FGDC elements that create standard searchable
metadata about data.
http://fgdc.er.usgs.gov/nsdi/nsdi.html
The NSDI encompasses
policies, standards, and procedures for organizations to cooperatively produce
and share geographic data.
The Federal Geographic Data Committee coordinates the
development of the National Spatial Data Infrastructure (NSDI).
http://fgdc.er.usgs.gov/metadata/contstan.html
The Content Standard for Digital
Geospatial Metadata (CSDGM), a common set of simple and compound data elements,
definitions, and terminology for the documentation of digital geospatial data.
http://www.fgdc.gov/metadata/meta_workbook.html
The CSDGM workbook, it really does help!
http://www.fgdc.gov/metadata/metadata.html
This is a source for additional
metadata resources, including information on training, tools, work groups,
FAQs.
http://geology.usgs.gov/tools/metadata/tools/doc/faq.html
This list of frequently
asked questions (FAQs) carries no official sanction with FGDC or USGS, but
provides good information on questions about FGDC metadata both general and
technical.
Federal Geographic Data Committee. Content Standard for Digital
Geospatial Metadata Workbook Version 2.0. Federal Geographic Data Committee.
Washington, D.C.
Federal Geographic Data Committee. FGDC-STD-001-1998. Content
Standard for Digital Geospatial Metadata (revised June 1998). Federal
Geographic Data Committee. Washington, D.C.
Maine Office of Geographic Information Systems. Data Standards
for Maine Geographic Information Systems. Maine Department of Administrative
and Financial Services, Bureau of Information Services, Augusta, Maine.
RTSe, 2000. Spatial GIS Metadata/Data Manager, User Guide,
Version 3.1 for Oracle 8. RTSe USA, Redmond, Washington.