Map Layers and Data Products
In the Land Cover branch, several different global land cover maps can be visualized on top of Google Earth. These include the GLC-2000, MODIS v.5 (2005, 2010-2012), GlobCover 2005, the ESA CCI land cover products for 2010 and 2015, GlobeLand30 for 2010 and a hybrid land cover product created by the group (See et al., 2015a). In addition, Hansen’s global forest change maps, the JRC water extent layer and the Global Human Settlement Layer (GHSL) can be viewed. Each of these global land cover products has a link to information about that dataset.
In addition to the global land cover maps, users can also view maps of spatial disagreement on Geo-Wiki. An example is provided in Figure 1. The disagreement was determined by examining the amount of definitional overlap between legend categories as described in Fritz et al. (2011) and expressed in the form of lookup tables. The lookup tables were then applied to each pair of land cover products to create maps of disagreement in forest, cropland and combined domains. These maps were created to highlight those areas where the global land cover products currently disagree and to then target our crowdsourcing efforts towards validating these areas using Google Earth. These disagreement maps have been registered in the Global Earth Observation System of Systems (GEOSS) portal so users can display them using a Web Map Service (WMS) or Web Coverage Service (WCS).
Figure 1: An example showing the disagreement between the GLC-2000 and MODIS in the cropland domain.
The Biomass Geo-Wiki branch contains numerous above ground live biomass and forest woody biomass layers as well as a hybrid forest mask for 2000 created by Schepaschenko et al. (2015) while the Cropland branch contains the IIASA-IFPRI hybrid cropland map for 2005 and a global field size map (Fritz et al. 2015) along with crop type distributions for 2005 produced using SPAM by IFPRI.
Another data product available on Geo-Wiki is the set of validations provided by the users along with photos uploaded via geo-wiki.org or the Geo-Wiki Pictures mobile app. The data provided by the users are stored in a Postgresql database along with their registration information. These contributions have been used in a number of different ways including the development of the global hybrid cropland map (Fritz et al. 2015), which can be viewed and downloaded from the Geo-Wiki Cropland branch, the validation of a map of land availability for biofuel energy production (Fritz et al. 2013) and the creation of a map of wilderness, among others (See et al. 2015b). Users can download their own validations as well as the validations of all other users from the site, which they can use for their own purpose. The data are also available from the Pangaea repository (Fritz et al. 2017).
