Internet distribution of data has increased the importance of metadata. Data custodians are able to release a dataset to the entire world for download without any personal interaction. The metadata record of a geospatial dataset can follow that to help ensure that the integrity and accountability for that data is maintained. Properly formatted metadata also allows for automated cataloguing, search indexing, and integration of datasets. Metadata has become so important that a common mantra within the geospatial community is Data without metadata isn't data, meaning that a geospatial dataset cannot be fully utilized and understood without metadata. The following section will list some of the common metadata tools that are available. The OGC standard for metadata management is the Catalog Service for the Web (CSW), which creates a metadata-based catalog system and an API for distributing and discovering datasets.
GeoNetwork is an open source, Java-based catalog server to manage geospatial data. It includes a metadata editor and search engine as well as an interactive web map viewer. The system is designed to connect spatial data infrastructures globally. It can publish metadata through the web using the metadata editing tools. It can publish the spatial data as well through the embedded GeoServer map server. It has user and group security permissions and web and desktop configuration utilities. GeoNetwork can also be configured to harvest metadata from other catalogs at scheduled intervals. The following screenshot is of the United Nations Food and Agriculture Organization's implementation of the GeoNetwork:
You can find out more about GeoNetwork at http://geonetwork-opensource.org/.
CatMDEdit is another Java-based metadata editor focused on the geospatial data from the National Geographic Institute of Spain and several collaborators. CatMDEdit can exchange metadata records using XML and Resource Description Framework (RDF) standards and style, and then transform the metadata for viewing in different formats; it also enables visualization of geospatial data, integration with gvSIG and has many other features. The CatMDEdit website is located at http://catmdedit.sourceforge.net/.