The HWSD is a 30 arc-second raster database with over 16000 different soil mapping units that combines existing regional and national updates of soil information worldwide (SOTER, ESD, Soil Map of China, WISE) with the information contained within the 1:5 000 000 scale FAO-UNESCO Soil Map of the World (FAO, 19711981).
The resulting raster database consists of 21600 rows and 43200 columns, which are linked to harmonized soil property data. The use of a standardized structure allows for the linkage of the attribute data with the raster map to display or query the composition in terms of soil units and the characterization of selected soil parameters (organic Carbon, pH, water storage capacity, soil depth, cation exchange capacity of the soil and the clay fraction, total exchangeable nutrients, lime and gypsum contents, sodium exchange percentage, salinity, textural class and granulometry).
Reliability of the information contained in the database is variable: the parts of the database that still make use of the Soil Map of the World such as North America, Australia, West Africa and South Asia are considered less reliable, while most of the areas covered by SOTER databases are considered to have the highest reliability (Central and Southern Africa, Latin America and the Caribbean, Central and Eastern Europe).
Further expansion and update of the HWSD is foreseen for the near future, notably with the excellent databases held in the USA: Natural Resources Conservation Service US General Soil Map (STATSGO) http://www.ncgc.nrcs.usda.gov/products/datasets/statsgo, Canada: Agriculture and AgriFood Canada: The National Soil Database (NSDB) http://sis.agr.gc.ca/cansis/nsdb and Australia: CSIRO, aclep, natural Heritage Trust and National Land and Water Resources Audit: ASRIS
The designations employed and the presentation of materials in Harmonized World Soil Database do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) the International Institute for Applied Systems Analysis (IIASA), International Soil Reference and Information Centre (ISRIC), Institute of Soil Science – Chinese Academy of Sciences (ISSCAS) or Joint Research Centre of the European Commission (JRC) concerning the legal status of any country, territory, city or area or its authorities, or concerning the delimitation of its frontiers or boundaries.
© 2008-2009 COPYRIGHT FAO, IIASA, ISRIC, ISSCAS, JRC
All rights reserved. No part of this Harmonized World Soil Database may be reproduced, stored in a retrieval system or transmitted by any means for resale or other commercial purposes without written permission of the copyright holders. Reproduction and dissemination of material in this information product for educational or other noncommercial purposes are authorized without any prior written permission from the copyright holders provided the source is fully acknowledged. Full acknowledgement and referencing of all sources must be included in any documentation using any of the material contained in the Harmonized World Soil Database, as follows:
Citation FAO/IIASA/ISRIC/ISSCAS/JRC, 2009. Harmonized World Soil Database (version 1.1). FAO, Rome, Italy and IIASA, Laxenburg, Austria.