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Geo-Wiki to enhance accuracy of global land cover maps

Laxenburg, Austria: Researchers at the International Institute for Applied Systems Analysis (IIASA), Austria, developed Geo-Wiki, an interactive web tool. It aims to improve the accuracy and extent of global land use and forest cover information. It uses Google Earth and information provided by a global network of volunteers to fill in ‘data gaps’ and to verify existing land cover information. In addition, researchers also launched a Geo-Wiki competition to raise awareness of the tool and to encourage community involvement in environmental monitoring.

The project aims at producing a hybrid land cover map which is more accurate than any current individual product can provide. Whenever a volunteer registers on Geo-Wiki portal, information is collected on where they live, their profession, and their local knowledge. They are asked to review locations – or ‘hotspots’ – where data is missing or where there is disagreement over the land cover. The data inserted by a volunteer is ‘quality assessed’ via control points.

This involves the use of an internal scoring mechanism which compares known validations with those provided by the volunteers and hence allows the Geo-Wiki team to identify those users that are able to provide high quality validations. Data is also systematically compared with input from other users as another way of assessing data quality. Volunteers are encouraged to submit photographs of the location to help in the validation of the land cover. The majority of registered volunteers to date have some professional association with remote sensing.

Once submitted the land cover information recorded in Geo-wiki is freely available for decision makers, land managers, or any member of the community anywhere in the world.

“Global land cover information available to policymakers and the research community today is derived from remote sensing,” said Dr Steffen Fritz, leader of the Geo-Wiki development team and research leader from the International Institute for Applied Systems Analysis (IIASA). “While there are several excellent regional and national land cover datasets already available that capture some basic information, there are still many regions where the information derived from satellite sources is conflicting, or inconsistent, across the datasets.”

“This means we cannot be certain of the spatial distribution of deforestation, how much land is being used for cropping or, for example, the extent of urbanisation. This has implications for how regions assess such things as their carbon storage potential, how much land could be available for food production or biofuel expansion, decisions that are becoming increasingly important as climate change and food security concerns escalate,” added Dr Fritz.

It is pertinent to mention here that several additional Geo-Wikis have also been developed. An agriculture Geo-Wiki aims to provide the most detailed coverage to date of the type and extent of agriculture, while urban Geo-Wiki helps users to better understand the percentage of the earth’s surface under urbanisation. Current estimates of the total land surface classified as urban vary from between 0.05 percent to 3 percent of the earth’s surface, a significant disagreement that the Geo-Wiki team hope to reduce. Other Geo-Wiki ‘branches’ currently developed include biomass cover, human impact, archaeology and regional Geo-Wiki.

To maximize the value of Geo-Wiki the developers are encouraging people to get involved. In a similar way to the immensely popular bird watching ‘eBird project’ (ebird.org) – which has some 48 million records of bird sightings globally – the value of Geo-Wiki will be realized through the involvement of the global community.

Geo-Wiki is a collaboration between the International Institute for Applied Systems Analysis, the University of Applied Sciences Wiener Neustadt and the University of Freiburg.

Source: IIASA