Knowing where agricultural land is located is crucial for regional and global food security planning, and information on field size offers a better understanding of local economic conditions. These are insights from Austrian scientists who produced two global maps that they say provide more detailed information on the world's cropland than has previously been available.

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The first, which has a very high (1Km) resolution, and shows the world's croplands as they were in the year 2005, was developed by the International Institute for Applied Systems Analysis (IIASA) in Austrian and the International Food Policy Research Institute (IFPRI). The mapmakers amassed data from other institutes and international organisations, and used crowd sourcing to recruit volunteers to check the accuracy of the map.

Commenting on the need for such a detailed look at croplands, IIASA researcher Steffen Fritz said, "Current sources of information on cropland extent are not accurate enough for most applications. The global cropland map is a low cost solution to fill this need."

"Getting an accurate crop map is particularly difficult in developing countries, where smallholder plots are tough to differentiate from the surrounding vegetation," commented Liangzhi You, who worked on the project for IFPRI. "Yet cropland information is fundamental to both policymakers and donors so that they can better target their agricultural and rural development policies and investments."

Global Field Size Map

The in-depth work allowed researchers to produce the first ever global field size map, based entirely on crowdsourced data collected through a project run by the Vienna-based institute. The crowdsourcing project created a global network of citizen scientists, who looked at thousands of high-resolution images of land cover to determine whether cropland was present or not, and produce an accurate depiction of field sizes.

Last year, IIASA's Dr Fritz won a Consolidator Grant from the European Research Council to continue and expand his mapping work. He and his colleagues are now working on more detailed field size mapping, in collaboration with Sokoine University of Agriculture in Tanzania.

Dr Fritz said, "Crowdsourcing has incredible potential for gathering this type of information, and it could be particularly valuable in Africa, where future food security is a major uncertainty."