Data Biosphere GNV8

  Summary Preview - Download 

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. Global Biochemical Cycles, volume one, pp. 61-86". Another recent article which is also useful is "Matthews, E. 1993. Global geographical databases for modelling trace gas fluxes. International Journal of Geographical Information Systems, volume seven, number two, pp. 125-142."

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/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). GRID LEGEND FOR NATURAL WETLANDS TYPES (MATTHEWS AND FUNG)

Class # Wetland Types ______ ____________

1 Forested bog

2 Non-forested bog

3 Forested swamp

4 Non-forested swamp

5 Alluvial formations

6 Tropical/Subtropical forest/Woodland

7 Temperate forest/Woodland

8 High-latitude temperate/Boreal forest/Woodland/Shrub

9 Shrubland; Xeromorphic foundations; Desert

10 Wooded grassland

11 Nonwooded grassland

12 Tundra

250 Water

251 Other (non-wetland)

GRID LEGEND FOR NATURAL WETLANDS "DATA SOURCES"

Class # Data Sources ______ __________

1 UNESCO + FAO + ONC

2 UNESCO + ONC

3 UNESCO + FAO

4 UNESCO

5 ONC + FAO

6 ONC

7 FAO

250 Water

251 Other (non-wetland)

GRID LEGEND FOR NATURAL WETLANDS "FRACTIONAL INUNDATION"

Class # Inundation ______ __________

0-100 = Percentages

250 Water

251 Other (non-wetland)

  PreviewSummary - Download






 DownloadSummary - Preview
http://www.grid.unep.ch/data/download/gnv8.tar.Z