Many factors, like growing population, deforestation, changing diets, and urbanization, are putting unprecedented pressure on land resources, particularly land for agricultural production. Estimates regarding the extent of cropland areas range between 1.22 and 1.71 billion hectares—a wide margin of uncertainty. Achieving food security will depend on establishing the facts “on the ground,” to optimize future land use planning.
Ecosystem Services and Management Program (ESM) in 2011 continued its initiative to collect and improve data on land use. A 2011 ESM study on uncertainty in global land cover maps, published in Environmental Research Letters, was downloaded more than 500 times, putting it in the top 3% of downloads from the IIASA Web site.
ESM is leading the drive among research and national map-making communities to share data and products to cover medium-term needs until new and improved remote-sensing products start coming on stream in a few years’ time. In 2011 five existing data sets for Africa—GLC-2000, MODIS Land Cover, GlobCover, MODIS Crop Likelihood and AfriCover—were combined by ESM and partners into a “synergy map” at 1 km resolution, where every pixel was compared or ranked to assess the likelihood or probability that it is cropland. The resulting cropland map has a proven accuracy of 83%, higher than the accuracy of the single individual maps, but still leaving a 17% gap that ESM are attempting to narrow by involving the global scientific and lay community in data gathering and verification of land cover through the Geo-Wiki crowd sourcing and visualization tool, hosted at IIASA.
In Geo-Wiki, volunteers review hotspot maps of global land cover disagreement and, based on local knowledge and what they see on Google Earth, determine whether the land cover maps are correct. Inputs are recorded in a database and photos uploaded, so that a new, improved global land cover map can be created in the future. In 2011 ESM were appointed to lead the GEO sub-task on agricultural mapping which will lead to the next-generation global hybrid cropland map.
Last edited: 19 July 2013
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