Land cover derived from remotely sensed products is an important input to a number of different global, regional and national scale applications including resource assessments and economic land use models. During the last decade three global land cover datasets have been created, i.e. the GLC-2000, MODIS and GlobCover, but comparison studies have shown that there are large spatial discrepancies between these three products. One of the reasons for these discrepancies is the lack of sufficient in-situ data for the development of these products.
In 2009 IIASA, the University of Applied Sciences Wiener Neustadt, and the University of Freiburg developed and set up a geospatial Wikipedia based on the Google Earth platform to address this issue; a crowdsourcing tool called Geo-Wiki has been developed. Geo-Wiki development has been financed by the European Commission via framework funding and an Austrian Funding Agency project called LandSpotting.
Geo-Wiki has two main aims:
Geo-Wiki is part of a growing trend to reverse the usual top-down flow of data by allowing Internet users from any region of the world to be involved in a global land cover validation exercise.
IIASA has combined existing cropland data sets from sub-Saharan Africa to create a new map with higher accuracy than existing maps. The cropland map, which has an estimated 83% accuracy, is available for review.
Working with the TU Vienna, we are developing a series of games linked to Geo-Wiki as an incentive to volunteers to provide information.
IIASA is developing a robust methodology to improve the quality of the validations provided by volunteers.
Volunteers are asked to indicate the land cover type of a given area based on what they can see on Google Earth. Their input is recorded in a database, along with uploaded photos, to be used in the future for the creation of a new and improved hybrid products.
Once in the system, Google Earth is displayed with the in-built functionality to rotate the Earth and to zoom into any land surface to begin land cover assessment. The user can also plot any of the global land cover maps (GLC-2000, MODIS, GlobCover) on top of Google Earth, or the user can display the disagreement maps between any pair of land cover products . These disagreement maps highlight the critical areas where further validation is needed.
It is these large areas of disagreement that Geo-Wiki is targeting in its crowdsourcing efforts.
Click here for more information on how to assess land cover.
COMPETITION.Geo-Wiki.org: Owing to the large amount of disagreement among global land cover products, the creation of a global hybrid land cover product is seen as a major step towards improvement. In that regard, the goal of this competition is to focus on the areas of greatest disagreement among the existing products.
Last edited: 25 August 2015
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