DOI: 10.5061/dryad.hqbzkh1jm
title: The biome inventory – standardizing global biogeographical land units

description: The subdivision of the Earth's terrestrial surface into different
 biomes, ecozones, bio-climatic realms or other large ecological land units
 is an essential reference for global biogeographical and ecological
 studies. Various classification schemes exist. They differ significantly
 in terms of the considered criteria for classification and the underlying
 methodology of class assignments. Evident divergences between global biome
 concepts are elusive, weakening hereon based analyses and assumptions.
 Compilation and standardization are essential for obtaining a framework
 that enables the comparison of different products. To address this need,
 we created a catalogue of standardized categorial maps comprising 31
 different global products based on various methodological approaches.
 Those were processed individually to facilitate their use in large-scale
 biogeographical and ecological analyses.
description: Spatial data of the selected
 classifications were retrieved from original sources depending on their
 availability. Certain concepts were manually digitized and geo-referenced
 as ESRI shapefiles based on scans of latest available map representations
 extracted from literature. Those classifications and others presented in
 vector format were transformed to grid data. A template raster file was
 created to serve as a reference for grid processing. All concepts were
 harmonized with this standard format at a spatial resolution of 10 km x 10
 km, over a global extent from 180°W to 180°E and 90°N to 90°S and with the
 coordinate reference system set to equal-area Mollweide projection. Any
 undefined classes were excluded. The values of all raster cells we
 transformed to numbers by interchanging the names of classes that are
 commonly character strings with distinct values (e.g., values
 "1" and "2" were assigned to "Tropical
 rainforest" and "Savanna"). Classes were sorted according
 to their centre's latitudinal deviation from the equator in ascending
 order from 1 until the count of different classes. Inland water bodies,
 oceanic islands, mountains and urban areas were defined as azonal classes;
 thus, consistent values were assigned (inland water bodies=95, oceanic
 islands=96, mountains=97, urban=98). All processed classifications were
 combined into one RasterStack object with 31 layers in chronological order
 from the most recent to the oldest classification. Legends of all maps
 were harmonized for consistency. They are provided in an ancillary text
 file in the same order like the RasterStack.
description: This data set contains a RasterStack
 object with 31 layers of standardized global biome and land-cover
 classifications (Biome_Inventory_RasterStack.tif). Legends of all maps are
 provided in an associated text file (Biome_Inventory_Legends.txt). They
 are presented in the same order like the layers in the RasterStack
 object. The data set can be
 processed with RStudio. Exemplary
 code to open and visualize the RasterStack of the biome inventory from the
 file "Biome_Inventory_RasterStack.tif" with legend data from the
 file "Biome_Inventory_Legends.txt" is presented in the
 associated README-file (README_biome_inventory.txt).