ISO 19115:2003 defines the schema required for describing geographic information and services. It provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data. This is revised by ISO 19115-2:2009 (Extensions for imagery and gridded data) and ISO/NP 19115-1, which is currently in development with a target publication date around mid-2012.
For more information: https://geo-ide.noaa.gov/wiki/index.php?title=Category:ISO_19115