The Tertiary Roads Density raster layer is part of the Global Roads Inventory Project (GRIP) dataset, developed to provide a more recent and consistent global roads dataset for use in global environmental and biodiversity assessment models like GLOBIO.

This map shows to which extent rainfed and irrigated agricultural systems as identified on SOLAW Map 1.3: "Major agricultural systems" suffer from land and / or water scarcity. Land scarcity in rainfed agriculture was assessed by comparing the rural population density, (obtained from GRUMP 2000, adjusted for UN data, excluding the urban areas indicated on the GRUMP dataset) with the suitability for rainfed crops as mapped for the Global Agro-ecological Zones 2000. Since land that is very suitable for rainfed agriculture can sustain more people than land that is not suitable, it was assumed that each suitability class has its own carrying capacity regarding population. On the map, land is considered scarce if the population density is higher that the highest quintile in the density distribution for each suitability class. Land scarce areas in climates with an Aridity Index lower than 0.5 (where the Aridity Index is defined as Yearly Precipitation divided by Yearly Reference Evapotranspiration) are considered both land and water scarce. Water scarcity in irrigated areas was assessed by combining the Map 1.2: Global distribution of physical water scarcity with the Global Map of Irrigation Areas. The areas equipped for irrigation are considered water scarce if already more than 10% of the renewable water resources in the river basin is consumed by irrigated crops.

Land area in km2 per 5 arcminute cell. This layer is part of the Global Roads Inventory Project (GRIP) dataset, developed to provide a more recent and consistent global roads dataset for use in global environmental and biodiversity assessment models like GLOBIO.