15. The GLASOD Digital Database

The Global Assessment of Human Induced Soil Degradation (GLASOD) was conducted by the International Soil Reference and Information Centre (ISRIC) at Wageningen, The Netherlands, as commissioned by the United Nations Environment Programme (UNEP). ISRIC produced a 1:10 million scale wall chart in 1990 and subsequently produced a digital data set.

In essence, the GLASOD data base contains information on soil degradation within map units as reported by numerous soil experts around the world through a questionnaire. It includes the type, degree, extent, cause and rate of soil degradation.

The GLASOD data set as processed by GRID consists of four files. The four files are : GLSDOCO.E00 , CALCAREA.E00 , GLSGEO.E00 , GLSMOLL.E00. The first two files are text files. The next two files are the actual GLASOD ARC/INFO coverages :

• GLSGEO is referenced in geographic coordinates (decimal degrees latitude and longitude) centered over the Greenwich Meridian. This is a very common general reference system which is handled by most GIS and image processing systems.
• GLSMOLL is referenced in the Mollweide equal-area projection (the parameters are listed in the above-mentioned text file).