Metadata, often called data about data, is important information. It is used to describe characteristics that are not incorporated into a data file. Metadata should describe the what, how, why and who about a dataset. What data was collectioned (and what format is it in); how the data was collected; why the data was collected; and who collected the data.

• Metadata ISO 19139 — ISO 19115 is an international standard preferred by leading data publishers and warehouses (i.e., British National Geospatial Data Framework, Australian Spatial Data Directory, UN Geographic Information Working Group, INEGI (Mexico) and Canadian Geospatial Data Infrastructure) worldwide. [more information]
• Controlled Vocabulary — Controlled vocabularies are highly useful in data discovery. ISO 19115 offers controlled vocabularies for several metadata elements but for domain specific ones such as keywords it is expected from user communities to come up with their own. [more information]
• Search Wizard — Search wizard allows data discovery over multiple and heterogeneous data sources. It relies on several web technologies such as Web Services, AJAX and OWL. CUAHSI Controlled Vocabulary and several other service ontologies comprise an important part of the search wizard. [more information]