Natural Wetlands Data Set

Documentation for Natural Wetlands Data Set (Matthews and Fung)  

The Natural Wetlands data set was compiled by E. Matthews at the
NASA/ Goddard Institute of Space Studies (GISS), Columbia
University, New York City, N.Y. USA. It shows the distribution
and environmental characteristics of naturally occurring wetlands
in a total of five data files, which are described as follows:  

a) Wetland Type - total of 12 categories derived mainly from the
UNESCO classification scheme;    

b) Vegetation Type of wetland areas from the UNESCO
classification scheme (178  classes);    

c) Soil Type of the wetland areas from the FAO Soil Map of the
World as modified  by Zobler (1986) in 107 classes;    

d) Fractional Inundation, or the percentage of each one degree
(lat./long.) grid cell  covered by wetlands from 0 to 100%; and   

e) Data Sources used to compile the above, including three
possible sources (FAO,  UNESCO and ONC - the Operational
Navigation Charts), and their various combinations in seven
groups.   

The five were developed to evaluate the role of wetlands in the
annual emission of methane from terrestrial sources, and have
been used as such.  

The reference for these data sets is "Matthews, E. and I. Fung,
1987. Methane emission from natural wetlands: global
distribution, area, and environmental characteristics of sources,
in Global Biochemical Cycles, volume one, pp. 61-86".  

Like the other Matthews data sets, the five Natural Wetlands data
files have a spatial resolution of one degree latitude/longitude,
consist of 180 rows (lines) by 360 columns (elements, pixels, or
samples) of data, and one byte/eight bits per pixel. Their origin
point is at 90 degrees North latitude and 180 degrees West
longitude, and they extend to 90 degrees South latitude and 180
degrees East longitude. At one degree resolution, each of these
data files comprises 64.8 kilobytes (kb).