What is Metadata?
Metadata is the technical word for 'data about data'. It is the term used to describe the summary information or characteristics of a set of data. In the area of geospatial information, or information with a geographic component, this normally means the What, Who, Where, When and How of the data. The only major difference between geographic metadata and the many other metadata sets being created for libraries, academia, professions, etc, is the emphasis on the spatial component - the 'where' element. Just as a consumer looks at the label on a food product to determine the ingredients, nutritional value and manufacturer, so to can a user of geospatial data review a metadata record to determine whether the dataset is fit for their purpose.

With the advent of GIS and the expanding use of digital data, the benefits and requirements for geospatial metadata are now well known. Consequently, there are recognised approaches to metadata documentation. The IGGI Guide: Principles of Good Metadata Management provides an excellent introduction to this subject.

Why collect Metadata?
With increasing amounts of data being created and stored (but sometimes not organised) there is a real need to document the data for future use - to be as accessible as possible to as wide a "public" as possible. There are significant benefits in doing so:

• Metadata helps organise and maintain an organisation's investment in data.
• It provides information about an organisation's data holdings in catalogue form or to brokers, resellers and clearing houses.
• Accessible metadata records help to avoid duplication of effort by ensuring awareness of the existence of datasets, and promotes the availability of geospatial data beyond the traditional geospatial community
• Users can locate all available geospatial data relevant to an area of interest or study. There is increasing pressure from customers for easier and quicker access to the right information, at little or no charge.
• Data providers are able to advertise and promote the availability of their data via online services.
• Metadata cataloguing goes some way towards compliance with Government directives relating to easier access to information - Information Age Government, Data Protection and Freedom of Information Acts, Public Records Act, Crown Copyright, etc.

What is Discovery Metadata?
There are three different levels of Metadata: Discovery metadata - which answers the question, "What datasets hold the sort of data I am interested in?"; Exploration metadata - "Do the identified datasets contain sufficient information to enable a sensible analysis to be made for my purposes?"; and Exploitation metadata - the process of obtaining and using the data that are required.

Standards regulated discovery level metadata is the minimum amount of information that needs to be provided to convey to the user the nature and content of the data resource. This falls into broad categories to answer the what, why, when, who, where and how questions about geospatial data.

• What - title and description of the dataset.
• Why - abstract detailing reasons for the data collection.
• When - when the dataset was created and the update cycles, if any.
• Who - originator and data supplier.
• Where - the geographical extent based on lat/long, co-ordinates, geographical names or administrative areas.
• How - how to obtain more information or order the datasets, formats, media access, constraints.

These broad categories are limited in number to reduce the effort required to collect the information, whilst still conveying to the user the nature and content of the data resource.

Click here for information on current metadata standards...