Maps showing the locations of language homelands are available for most countries of the world. Most of the maps make use of polygons to show the approximate boundaries of the language groups. No claim is made for precision in the placement of these boundaries, which in many instances overlap with those of other languages. Reference numbers are used on some maps where space does not allow the placement of language names. For some maps where the language boundaries are not known, the names or numbers appear alone.
The earliest maps in Ethnologue were hand drawn. Maps of Central and South America were commissioned for the 10th edition, and some maps of Africa were added in the 11th. For the 12th edition computer-generated maps were developed as part of the Language Mapping Project carried out jointly with Global Mapping International (GMI). For the sixteenth edition, all of the maps were redrawn with a new and clearer design. The current maps are drawn using ArcGIS® software published by Esri®. The capabilities afforded to us by a new generation of software have made it possible to improve the way that we show the family association of each language and the overlap of languages. We continue to increase the level of geographic detail included in the maps to aid in the location of languages within countries.
Current maps are drawn against the backdrop of the Seamless Digital Chart of the World (SDCW) published by GMI. The SDCW has a finer level of resolution than the base map used in editions prior to the 16th. In that edition, all the language polygons were repositioned to fit the greater detail of geographic features offered by that new database. This is an ongoing process and we continue to improve the accuracy and precision with which the language areas are plotted, particularly with the increased use of location data collected by GPS units and satellite imagery.
The introduction of GPS data has also meant that the data is becoming increasingly detailed. Smooth generalized curves are being replaced by more complex features and, in some countries, we are now able to provide a more accurate representation of the complexity where speakers from several language groups live in the same area. We continue to look for ways to improve the depiction of the language groups on the maps. The change to a primarily online format and multiple print volumes has given greater freedom to increase the number of maps. We have taken advantage of this to redesign the maps of some countries at larger scales. Also we continue to add to the maps the changes in the ISO 639-3 inventory of languages.
We acknowledge use on some maps of national park data adapted from the International Union for Conservation of Nature (IUCN) and United Nations Environment Program - World Conservation Monitoring Centre (UNEP-WCMC) (2015), The World Database on Protected Areas (WDPA), is available at www.protectedplanet.net.
The maps use a variety of map projections: African equatorial countries use the Sinusoidal projection; other equatorial countries use the Mercator (cylindrical) projection; maps of countries in higher latitudes use the Lambert Conformal Conic projection.
As with all of the content of the Ethnologue, no political statement is intended by the identification of any territory separately in a map or in the language listings nor by the placement of any boundary lines for any languages or countries on any map.