Note: In the layer names mentioned in this chapter, xx represents the ISO2 country
code, xxx represents the ISO3 country code and xxxx represents a 4-letter
country code. A list of associated country codes is included in the Appendices below.
The Administrative Layers are named to reflect the names of the administrative areas used by the country. The number of layers varies from country to country. For example, Slovenia has only two layers whereas Belgium has six. The Administrative 0 Layer contains the national or international boundaries and rest layers follow the administration hierarchy present in country.