|
|
|
DOCUMENTING METADATA Metadata is really just data about data. The information contained in metadata documents the creation of a dataset and gives the user an idea of what the cartographic product to which it is attached was designed to do. Metadata is saved in text file format by the author of the finished geospatially referenced data. The metadata file should accompany the coverage files anytime they are distributed so there is as little risk of misinterpretation of the data as possible. The following items are provided as an example of some of the critical information about the GIS data that must be included in the metadata document: the purpose of the coverage, use restraints, data sources, map projection, datum, database attribute categories, author contacts, etc. Metadata can actually be written in any text format, however this is not recommended. There are several searchable metadata database servers available on the internet that only accept metadata files that conform to one of the standard formats. Metadata Formats The most popular databases such as the Federal Geographic Data Committee (FGDC), the National Biological Service (NBS) use the FGDC and NBII standards respectively. The NBII standard is really the FGDC standard with additional categories built on. The following FGDC site is the authority for information concerning the FGDC standard http://www.fgdc.gov/ to which the USGS and other federal agencies must adhere. Other known standards are the NII and GILS. Metadata Database Servers Most metadata clearinghouses allow the user to search for data from participating sources, view the metadata, and provide links to the actual data sets. NWRC has established a clearinghouse node with the National Biological Information Infrastructure Clearinghouse. The NBII clearinghouse is a participating node on the larger FGDC National Spatial Data Clearinghouse. To access the NBII
Metadata Clearinghouse Gateway, please go to NBII
Clearinghouse To access the FGDC
NSDI Clearinghouse, please go to FGDC
Clearinghouse. Data Types Finally, each metadata standard has different templates for different dataset types, i.e. DEMs, DLGs, various data scales so be cautious to select the right template for the standard you choose. More Information Resources You can get a wealth of information at the USGS Federal Geographic Data Committee website that explains how metadata came into being and what rules govern its usage. |