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The Global Administrative Unit Layers (GAUL) is an initiative implemented by FAO within the EC-FAO Food Security Programme
funded by the European Commission (http://www.foodsecinfoaction.org/News/news_06_06.htm). The GAUL aims at compiling and
disseminating the most reliable spatial information on administrative units for all the countries in the world, providing
a contribution to the standardization of the spatial dataset representing administrative units.
The GAUL always maintains global layers with a unified coding system at country, first (e.g. regions) and second administrative
levels (e.g. districts). In addition, when data is available, it provides layers on a country by country basis down to third,
fourth and lowers levels.
The overall methodology consists in a) collecting the best available data from most reliable sources, b) establishing validation
periods of the geographic features (when possible), c) adding selected data to the global layer based on the last country
boundaries map provided by the UN Cartographic Unit (UNCS), d) generating codes using the GAUL Coding System and e) distribute
data to the users (see GAUL Doc01 Ver17.pdf)
Because the GAUL works at global level, controversial boundaries can not be ignored. The approach of the GAUL is to maintain
disputed areas in such a way to preserve national integrity for all disputing countries (see GAUL Doc01 Ver17.pdf and
disputed_areas.dbf).
The coastal line of the GAUL is mostly compliant with the coast of the International Boundary map delivered by UNCS except
for some countries (e.g. Viet Nam, India, Bangaldesh, etc.) where it has been updated according to the satellite images
(e.g. Landsat ETM). For the next releases of the GAUL, the updating process of the coast-line will go on, country by country,
through a comparison with the satellite images.
The GAUL is released once a year and the target beneficiary of the GAUL data is the UN community, the Universities and other
authorized international and national institutions/agencies. Data might not be officially validated by authoritative national
sources and can not be distributed to the general public. A disclaimer should always accompany any use of the GAUL data.
About 21 countries have been updated respect to the previous release (see countries_updated.dbf).
The GAUL keeps track of administrative units that has been changed, added or dismissed in the past for political causes.
Changes implemented in different years are recorded in the GAUL on different layers. For this reason the GAUL product is
not a single layer but a group of layers, named "GAUL Set" (see Gaul_Set.pdf).
The GAUL 2009 is the fifth release of the GAUL Set, which now includes the following files:
- G2009_2008: These layers have to be used to link all the datasets that refer to year 2008
- G2009_2007: These layers have to be used to link all the datasets that refer to year 2007
- G2009_2006: These layers have to be used to link all the datasets that refer to year 2006
- G2009_2005: These layers have to be used to link all the datasets that refer to year 2005
- G2009_2004: These layers have to be used to link all the datasets that refer to year 2004
- G2009_2003: These layers have to be used to link all the datasets that refer to year 2003
- G2009_2002: These layers have to be used to link all the datasets that refer to year 2002
- G2009_2001: These layers have to be used to link all the datasets that refer to year 2001
- G2009_2000: These layers have to be used to link all the datasets that refer to year 2000
- G2009_1999: These layers have to be used to link all the datasets that refer to year 1999
- G2009_1998: These layers have to be used to link all the datasets that refer to year 1998
- G2009_1997: These layers have to be used to link all the datasets that refer to year 1997
- G2009_1996: These layers have to be used to link all the datasets that refer to year 1996
- G2009_1995: These layers have to be used to link all the datasets that refer to year 1995
- G2009_1994: These layers have to be used to link all the datasets that refer to year 1994
- G2009_1993: These layers have to be used to link all the datasets that refer to year 1993
- G2009_1992: These layers have to be used to link all the datasets that refer to year 1992
- G2009_1991: These layers have to be used to link all the datasets that refer to year 1991
- G2009_1990: These layers have to be used to link all the datasets that refer to year 1990
The GAUL project does not implement changes dated before 1990.
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