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Home > How to serve a OneGeology WMS > WMS Profile > Layer metadata > Geographic Extent

2.5.1 Geographic extent

2 star accreditation requirement

For a 2 star accredited service, ALL OneGeology layers must conform to these naming protocols.

The first piece of information is the Geographic extent. Geographic extent should begin wherever practically possible with the Country of the layer extent, even if the layer only covers part of a country, or if the layer covers all of one country (use that as the country code) and some of the surrounding landmass or sea area. Country information is codified using the ISO 3166-1 three-letter country codes (

When the layer covers an area such as a defined region, state or province within a country, you should state the country code first and then the provincial information. Provincial information should wherever practically possible be codified using the ISO 3166-2 codes (

For example:

  • The US state of Kentucky would use US-KY
  • The semi-autonomous region of Flanders (Northern Belgium) would use BE-VLG

Note, the ISO 3166-2 codes use a 2 letter country code then hyphen then provincial code.

If you are using your own provincial code (known within your county perhaps but not codified by ISO), you should use the three letter ISO country code, then a space (not a hyphen), and then your provincial code.

The OneGeology Portal divides countries and regions using the United Nations (UN) "World macro regions and components" listing. If you are serving regional data wider than country level, you should use the UN regions ( where possible.

Where the layer coverage doesn’t correspond to a country and/or when no ISO code or UN region exists to describe the coverage, you should use a short geographic name such as "World".

Section last modified: 28 June 2013

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