All the world's cropland is a difficult task. Yet the competition for land among developers, growers and other parties makes getting an accurate count of the world's arable acres especially important as the planet's population grows.
The new global cropland map shows the extent of land dedicated to farming in 2005, and the field-size map illustrates different approaches to farming. It turns out that medium and large fields dominate in North America, central South America, Europe and Australia, while small fields pepper the farming regions in Africa, India, Southeast Asia and China.
The first map shows global cropland percentages at 1 kilometer resolution for the year 2005. It was developed by the International Institute for Applied Systems Analysis (IIASA) and the International Food Policy Research Institute (IFPRI) using a hybridization of multiple data sources contributed by many other institutes and organizations, combined with crowdsourcing validation data where volunteers used high-resolution data to check the accuracy of larger-scale maps.
The new global cropland map is more accurate, by virtue of increased agreement between different datasets on cropland cover. The researchers used a likelihood method to quantify the level of uncertainty, using agreement between maps to assign a likelihood to each area. See explains, "Where all maps agree there is cropland, there is a higher likelihood that cropland is present."
