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Metadata education suggestions and materials for:
Learning Material | Preparatory topics | Complementary topics | Vocabulary
Learning Outcomes
- Understanding of what metadata is in the context both of geospatial data and the broader information science realm
- Awareness of the basic content and format of metadata
- Understanding metadata as one of three basic components of GIS data
Complementary topics:
Vocabulary
Vocabulary definitions
- geospatial data
- clearinghouse
- dataset
- Content Standard for Digital Geospatial Metadata
Material for this topic
"Metadata is data about data. It describes the attributes and contents of an original document or work, and can relieve potential data users of having to have full advance knowledge of a dataset's existence and characteristics. In other words, standard bibliographic information, summaries, indexing terms, and abstracts are all surrogates for the original material, hence metadata. The term is generally applied to electronic resources and refers to "data" in the broadest sense--datasets, textual information, web pages, graphics, music, and anything else that is likely to appear electronically." (Milstead and Feldman 1999).
"The term metadata has been used only in the past 15 years, and has become particularly common with the popularity of the World Wide Web. But the underlying concepts have been in use for as long as collections of information have been organized. Library catalogs represent a well established variety of metadata that has served for decades as collection management and resource discovery tools." (DC)
"Metadata is simply documentation for a digital geospatial dataset. It is a text document that describes the who, what, when, where, why and how questions about the data, so that a potential data user can decide whether or not the data is appropriate for his/her use."
"Metadata, sometimes called "data about data", describe the content, quality, condition, and other characteristics of data. It is through the evaluation of the metadata that a user can determine if the data meets the user's needs. (NC-CGIA)
Metadata describe different aspects of data, including:
- Identification -- What is the name of the data set? who developed the data set? What geographic area does it cover? What themes of information does it include? How current are the data? Do restrictions exist for accessing or using the data?
- Data Quality -- How good are the data? Is information available that allows a user to decide if the data are suitable for his or her purpose? What is the positional and attribute accuracy? Are the data complete? Were the consistency of the data verified?
- Spatial Reference and Organization Information -- How is the data referenced to the real world (coordinate systems, datums)? How is the data organized (data models, topology)?
- Entity and Attribute Information -- What geographic information (roads, houses, elevation, temperature, etc.) is included? How is the information encoded? Were codes used? What do the codes mean?
- Distribution -- From whom can I obtain the data? What formats are available? What media are available? Are the data available online? What is the price of the data?"
"Begin by realizing that METADATA IS A PART OF GEOSPATIAL DATA. Just like the user's manual is part of your car, the deed is part of your property and your medical records are part of who you are, metadata is part of what geospatial data IS." (NC-CGIA)
Metadata is one of three components of geospatial data
 A traditional description of GIS data is that it is more than a computerized map, and it is more than just a database: it both information about spatial location and relationships (coordinates, topology) and attribute (descriptive) information about geographic features in database format. However, this description is incomplete without metadata. GIS software systems currently "read" both the spatial and attribute information; soon standard GIS software will also automatically read metadata information, and integrate it into standard GIS functions such as overlay and transformations, informing data users about the data characteristics even as they are using it. GIS data should be described as having three components: spatial information, attribute information and metadata information.
Forms of Metadata
"Perhaps the most common form of metadata is a file folder filled with notes on data sources and procedures used to build the data. Ideally, this information should formatted to be compliant with the Content Standards for Digital Geospatial Metadata (CSDGM), the U.S.-endorsed standard that is required for all federal agencies to use (see Overview of the metadata content standard for more details). CSDGM compliant digital metadata may be created, stored, and used in a variety of formats. The most basic is an ASCII text document. An ASCII document is easy to transfer to other users independent of the hardware/software platform they use. Another common format is Hypertext Markup Language (HTML). HTML provides an attractive way to view metadata using a browser such as Netscape. Software also exists to convert metadata from a text format into a format that can be indexed and searched on the web through interconnected clearinghouses, enabling data discovery. (Hart and Philips) .
Who uses metadata?
Anyone who wants to use GIS data (also called spatial or geospatial data) should know how to use metadata. "Using" metadata really means knowing how to read it, how to extract information that you need to know about a certain dataset. Knowing how to read metadata depends on what you will be using it for:
- to find datasets (show me all datasets produced since 1990 containing landuse information)
- to determine whether the dataset is appropriate for certain uses (fitness-for-use)
- to manage datasets (a record of changes, updates, procedures used)
- to extract information needed to correctly use datasets (perform projection transformations, select on certain attributes).
Who creates metadata?
Anyone who creates or modifies data should know how to create metadata. This does mean that they need to know how to produce it according to the specifics of the U.S.-endorsed standard, but they should know what the basic content of almost all metadata standards is. They should know how to describe their dataset's quality in terms of accuracy, sources, and development processes as well describe what spatial reference system the data is in and what type of spatial organization it has. These descriptions need to be in either a written or digital format in order to be metadata. There is no such thing as "metadata in the head" because the definition of metadata is "data about data" or "data documentation".
References
Milstead, J. and S. Feldman, 1999. "Metadata: Cataloging by any other name..." Online, Inc. (magazine article, published January 1999): http://www.onlineinc.com/onlinemag/metadata/
Dublin Core Metadata Initiative (frequently asked questions)
The Metadata Primer by David Hart and Hugh Philips
http://www.lic.wisc.edu/metadata/metaprim.htm
NOAA Coastal Services Center: metadata power point presentation (graphics)
North Carolina Center for Geographic Information and Analysis, "Accessing Data Tutorial" http://cgia.cgia.state.nc.us:80/tutorials/index.html
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