See the complete article: Publicly available global environmental layers

  • Edited by: T. Hengl

The current global geological map approved by the Commission for the Geological Map of the World is the 1:25M Geological Map of the World (Bouysse, 2009; maps not available publicly). The world geological maps are now being integrated via the OneGeology project which aims at producing a consistent Geological map of the world in approximate scale 1:1M (Jackson, 2007); progress can be followed via the interactive portal. USGS has several data portals, e.g. that allow browsing of the International Surface Geology (split into South Asia, South America, Iran, Gulf of Mexico, Former Soviet Union, Europe, Carribean, Bangladesh, Asia Pacific, Artic, Arabian Peninsula, Africa and Afganistan). Hartmann and Moosdorf (2012) have assembled a global, purely lithological database called GLiM (Global Lithological Map). GLiM consists of over 1.25 million digital polygons with classified in three levels (a total of 42 rock-type classes).

USGS jointly with ESRI has released in 2014 a Global Ecological Land Units map at 250 m resolution. This also includes world layer of rock types. This data can be downloaded from the USGS site.

Geological ages based on the surface geology.

Soil and geology maps are especially important for spatial prediction of distribution of vegetation and species. One harmonized global soil-type map is the USGS Global Soil Regions map at resolution of 60 arcsec, and which is based on the FAO-UNESCO soil map. The USDA global soil data is also available via ftp. USDA Soil Survey Division also distributes the global map of wetlands (includes: upland, lowland, organic, permafrost and salt affected wetlands).

FAO, IIASA, ISRIC, ISSCAS, JRC have produced in 2007 a 1 km resolution gridded soil-class map, produced by merging various national soil maps. This product is also known as the Harmonized World Soil Database (v 1.1). Global HWSD-derived soil property maps for top- and sub-soil can be download as geotifs here.

Major FAO soil groups based on the Harmonized World Soil Database.
Top-soil pH (H2O) based on the HWSD.

Fisher at al. (2008) maintain a global map of Global Agro-Ecological Zones (GAEZ). From the IIASA website you can download global maps of soil terrain and climate constraints to rain-fed agricultural production, suitability results for 27 crops under rain-fed conditions, and land with cultivation potential. The GEAZ product can be used jointly with the HWSD and corresponds to about the same scale.

A list of seven gridded soil property maps (at resolution of 5 arc-minutes) — soil-carbon density, total nitrogen density, field capacity, wilting point, profile available water capacity, thermal capacity, and bulk density — is available via the IGBP-DIS data set. Some additional soil property maps such as pH and soil moisture, can be also obtained from the Atlas of Biosphere project. Global Carbon storage in soils is available from the WRI website. Status of the soil information in the world can be also followed via David G. Rossiter's compendium of On-Line Soil Survey Information.

ISRIC — World Soil Information maintains a global soil profile database with over 12,000 profiles and over 50 analytical and descriptive parameters (Batjes, 2009). In 2013 ISRIC has released the SoilGrids1km product — a gridded soil information system at 1 km resolution produced using automated mapping (statistical and geostatistical models). The predictions are based on a compilation of over 110,000 soil profile data and some 80+ covariate layers available on this data portal. GeoTiffs of SoilGrids1km are available for download from www.soilgrids.org.