Data Standards - Metadata
 

About Metadata

Metadata is data about the data. It consists of information that describes spatial data and is used to provide documentation for data products. For example, metadata describes the format, geographic boundary, projection, coordinate system, availability and cost, etc., of a spatial data set (i.e. road network data, political boundary data, and satellite imagery). Metadata is the who, what, when, where, why, and how of spatial data.

US Geological Survey Metadata FAQ (Frequently Asked Questions)

Why use or create metadata?  There are three major advantages for using or creating metadata:

1) To help organize and maintain an organization's spatial data.

Metadata will allow an organization to keep track of what data products they own or are creating. Employees may come and go but metadata can catalogue the changes and updates made to each spatial data set and how each employee implemented them.

2) To provide information to other organizations and clearinghouses to facilitate data sharing and transfer.

It makes sense to share existing data sets rather than producing new ones if they are already available. Metadata facilitates this process by documenting what each data set consists of. Metadata tells a prospective buyer exactly what he is getting before purchasing a data set.

3) To document the history of a spatial data set.

Spatial data sets rarely stay in their original format. Metadata documents what changes have been made to each data set, such as changes in geographic projection, adding or deleting attributes, editing line intersections, or changing file formats. All of these could have an effect on data quality.

Remember, the key purpose of metadata is to facilitate and improve the retrieval and sharing of information.

 

Metadata Standards

There are different national and international metadata standards currently being implemented. The United Stated Federal Geographic Data Commission (FGDC) has adopted the Content Standard for Digital Geospatial Metadata (CSDGM), Australia has a standard implemented by the Australia New Zealand Land Information Council (ANZLIC), and the European Union (EU) is working to implement an European Geographic Information Infrastructure (EGII). Currently, the International Organization for Standardization (ISO) is developing a geospatial metadata standard. (ISO TC211)

 

Metadata Clearinghouses

A geospatial clearinghouse provides access to digital spatial data by searching metadata.

A clearinghouse site indexes all of its metadata which will enable a user to search for spatial data by submitting a query. If a match is found, all relevant metadata will be displayed to the user. Clearinghouse sites are encouraged to provide hypertext linkages within their metadata entries that enable users to directly download the digital data set in one or more formats or give instruction on how to obtain the data.

Geospatial Metadata Clearinghouses

NSDI Clearinghouse Nodes

FGDC Geospatial Data Clearinghouse

Shenandoah Valley National Geospatial Data Clearinghouse - (This site is currently down)

Wisconsin Land Information Clearinghouse (WISCLINC)

 

Table 4: Geospatial Metadata tools

ArcView Metadata Collector v. 2.0

The ArcView® Metadata Collector v 2.0 is an easy to use software application which can be utilized by any ArcView 3.x user without having to fully understand the Federal Geographic Data Committee's (FGDC) "Content Standards for Digital Geospatial Metadata." The tool provides a dialogue for creating FGDC compliant metadata for most data types supported by ArcView. The tool automatically extracts information (metadata) such as bounding coordinates, spatial data organization information and attribute information. In addition, the tool allows users to store information as .dbf and text (.txt) files that can be edited, if needed, and reused for subsequent metadata records. The application generates output in both text and HTML formats. If you are creating metadata for an ARC/INFO® coverage, you also have the option of generating an INFO file that will become part of that coverage.

cns (Chew and Spit)

cns (chew and spit) is a pre-parser for formal metadata designed to assist metadata managers convert records that cannot be parsed by mp into records that can be parsed by mp. It takes as input a poorly-formatted metadata file and, optionally, a list of element aliases, and outputs (1) a metadata file that can be read by both mp and xtme and (2) a file listing all of the lines that it could not figure out where to put.

This is especially useful for clearinghouses which may collect metadata from source agencies producing metadata differing in format because of the metadata tool or template employed at each agency, or because the agency metadata profile differs from the CSDGM.

Corpsmet 95

Corpsmet95 is a CSDGM tool developed for the U.S. Army Corps of Engineers by Coastal Oceanographics, Incorporated. It is a version of, or probably identical to, the commercial product Metagen32.

FGDCMETA (AML)

FGDCMETA.AML is an extremely simplified variant of DOCUMENT.AML that generates metadata files in ASCII text from Arc/Info geo_datasets in a UNIX or NT environment. File structure and content conform with the FGDC Content Standard for Digital Geospatial Metadata. The output template is intended to be customized to the individual user's needs (which requires rudimentary knowledge of AML). Resulting files are intended for use with other metadata tools that conform to the FGDC metadata standard (such as xtme, tkme and mp).

MP (Metadata Parser)

This program is a compiler to parse formal metadata, checking the syntax against the FGDC Content Standard for Digital Geospatial Metadata and generating output suitable for viewing with a web browser or text editor. It runs on UNIX systems and on PC's running Windows 95, 98, or NT. MP generates a textual report indicating errors in the metadata, primarily in the structure but also in the values of some of the scalar elements (i.e. those whose values are restricted by the standard).

TKME

The editor shares a considerable amount of its code with its companion product, Xtme, which is specifically for Unix systems and is based on the Athena widget set of the standard X Window System distribution. Both Tkme and Xtme are closely allied with mp, a compiler for formal metadata, whose purpose is to verify that the syntactical structure of a file containing formal metadata conforms to the FGDC standard, and to reexpress the metadata in various useful formats. The editors are intended to simplify the process of creating metadata that conform to the standard.

Xed (text editor)

Xed is a programmer's text editor for use on UNIX computers with the X Window System, Macintosh computers, and 80386-based MS-DOS computers. It is designed to be small, fast, simple to use, and easy to customize.

 

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