What Metadata Is and Why It Is Important


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What is METADATA?

The Federal Geographic Data Committee has adopted a standard for the contents of digital geospatial metadata which includes this definition:
"Metadata is data about the content, quality, condition, and other characteristics of data".

WLIA's Metadata Task Force has also developed a definition tailored to land information:

"Metadata is that collection of data, information, or knowledge that relates to land information, and that is helpful in locating, evaluating, comparing, accessing, and/or using land information. As such, metadata can reveal background at a general or detailed level, and can be highly structured or casually organized".

More generally, the term "metadata" refers to background information about something. A library's card catalog is an example of simple metadata about the books in the library. More detailed metadata would be the abstract of each book. And deeper yet would be the introduction, table of contents, and glossary in each book.

In the broad field of information management, metadata is that "stuff" that helps a person locate and then understand data, whether that data is in the form of a simple list, a spreadsheet, a database, a CAD drawing, or a GIS "map". Especially when data is computerized, it can become impossible to understand its essential details without appropriate background information.

Consider the important supporting information needed to use a computerized map:

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Why is metadata important to the land information community?

Metadata serves as a guidebook, as a catalog, and as insurance. In these ways, it is indispensable in efficiently and effectively using and sharing land information.

Without its accompanying metadata, the fitness for use of a given data set is unknown, and its usefulness is significantly impaired.

Before even trying to use someone else's data, a person can spend a huge amount of time simply searching to discover its existence unless a metadata catalog is available for browsing.

Data may last for centuries, but people have imperfect memories. And when people change jobs and retire, they often take their mental metadata with them.

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How can metadata benefit individual organizations?

An organization needs to document its valuable data holdings, and to develop systems to provide that documentation to those who need it. In this way, metadata represents insurance for an organization, protecting its investment in data.

Besides protecting its internal investment, an organization can make effective use of metadata maintained by other organizations. By searching this external metadata, an organization can quickly determine the availability, quality, structure, and content of data that is external but which may be useful. With this knowledge, the organization can make sound strategic decisions about its information management.

After selecting, ordering, and receiving external data, an organization needs metadata to guide proper use of that data. In this way, metadata supports effective datasharing.

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Who has addressed metadata issues so far?

There are a number of ongoing efforts in Wisconsin to create and maintain metadata, and to make it available. The Wisconsin DNR GIS Database User's Guide is a fine example of a printed document that is useful to people both inside and outside that agency. Winnebago County has begun to record background information on its digital geographic database. The Wisconsin DOT has built computer programs that prompt operators to enter documentary information during a geographic data editing session.

Many organizations maintain various files, notes, and reports that document their land information . However, these records are rarely organized into a single standardized searchable system.

The State Cartographer's Office is part of a national project to collect certain test metadata in computerized form, and to make them available for anyone to search via the Internet. Several federal, state, and local governments are cooperating in this work, which is funded by the Federal Geographic Data Committee and by the Wisconsin Land Information Board (WLIB).

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How would someone begin developing metadata now?

The first step is to inventory and evaluate the land information that currently exists, and any metadata related to it. This activity will identify the most critical missing metadata. Then an auditing process can begin, to collect and begin building the metadata.

Another important component is to plan for the on-going collection of metadata that documents any new data that is being considered. It will be far easier to collect accurate and detailed metadata at the time the data is being developed, than afterward. A plan can also be made to maintain the metadata so that it reflects changes made to the data over time.

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In what form would someone collect their metadata?

People are busy trying various approaches to this problem. The recent development of a national standard for the contents of digital "geospatial metadata" has been a big help. A standard set of documented elements will make it easier for other people to search through a variety of metadata developed by many organizations.

Traditionally, metadata has been collected in varying forms. Yet the form may not be as important as what metadata is collected and whether it is accessible and usable.

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How would I learn more about this subject?

WLIA's Metadata Task Force is offering a session at the WLIA 1995 Annual Conference. The Federal Geographic Data Committee is also presenting a half-day pre-conference workshop.

In addition, there are a number of printed documents that explain concepts and provide examples. Contact the State Cartographer's Office for more information about these documents.

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How will these efforts be integrated over time?

Various national research efforts and other cooperative ventures currently underway should help us determine the best ways to collect and maintain metadata.

At the same time, as metadata activities increase, tools are being developed that will assist and guide us in documenting our data holdings.

The WLIA, the WLIB, and others in Wisconsin are working closely with national efforts. Both organizations continue to emphasize the importance of this issue to all levels of government and the private sector, so that metadata is understood and implemented in an integrated fashion for Wisconsin.

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How will the Wisconsin Land Information Program affect the approach that state and local agencies take to metadata?

The Wisconsin program relies heavily on a distributed network of custodians who each develop and share land information with others. This arrangement means that metadata describing the land information is crucial to ensure that users are aware of and can evaluate available land information, and therefore use it properly.

Each county land information office (LIO) has an explicit role as a local clearinghouse. Effective metadata practices will help LIO's carry out this responsibility to provide information about land information held by the county and other entities within the county.

In addition, the WLIB adopted a rule in 1994 that any land information developed with program grant funds must be documented and the resulting metadata provided back to the Board for inclusion in its statewide clearinghouse. At the present time, the Board has suspended this requirement pending development of a reporting mechanism. The current experiments in metadata capture and management, across Wisconsin and the nation, will provide the Board with appropriate guidance.

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How will local clearinghouses relate to a statewide clearinghouse?

Actually, metadata available from a statewide clearinghouse may be brief compared to greater amounts of detailed documentation that may be maintained by the local custodian. The statewide clearinghouse can be an initial point of contact, filtering and redirecting requests for more detailed information from the appropriate custodian.

A custodian may choose to supply relatively detailed metadata along with the land information it delivers to a requester, so that secondary user can make best use of the information. In addition, the custodian may hold even more detailed metadata that documents the fine points of internal procedures, equipment testing, operator training, data development protocols, etc.

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What can WLIA, other organizations, and concerned individuals do to make metadata available?

WLIA is interested in promoting effective datasharing. Metadata is a key element in making this happen.

As leaders within the state land information community, WLIA members can participate in the dialogue and help shape the emerging world of metadata. In the future, we shouldn't have to wonder about the accuracy, completeness, timeliness, or availability of land information; instead we should simply be able to consult some easily accessible metadata and then get on with our real work.

This is the legacy that the WLIA Metadata Task Force is helping to build. We need your cooperation, ideas, and energy to assist in shaping this critical part of our future!

Organizations and individuals can spread the word, volunteer for experiments, and provide critical evaluations. Ultimately, the entire land information community will benefit.


Note: This 4-page flyer was produced by Bob Gurda, Diann Danielsen, and Brenda Hemstead, with assistance from their fellow members of the Wisconsin Land Information Association's (WLIA) Metadata Task Force.

If you have any questions or comments about this flyer please contact the Task Force's Chair, Diann Danielsen, at 608/262-8776, fax 608/262-5205.


Revised August 28, 1995 by BLH