World Reference Base for Soil Resources (4th Edition, 2022)

[brownag]

• Adds source data, data-raw script, and dataset/documentation for wrb_4th_2022

A list containing three data.frame elements "rsg", "pq", and "sq" providing information on the 'Representative Soil Groups', 'Principal Qualifiers,' and 'Supplementary Qualifiers,' respectively.
Each element has the column "code" which is a number (1-32) referring to the position in the Reference Soil Groups, and the column "reference_soil_group" which is the corresponding group name.

• The data.frame "rsg" has column "criteria", describing the logical criteria for each Reference Soil Group.
• The data.frame "pq" has qualifier names in column "principal_qualifier" and "sq" has column "supplementary_qualifier". The "pq" and "sq" qualifier names may be single qualifiers, or several related qualifiers separated with a forward slash " / " Both data.frames containing qualifiers have a qualifier_group column which can be multiple related qualifiers separated with a forward slash.

IUSS Working Group WRB. 2022. World Reference Base for Soil Resources. International soil classification system for naming soils and creating legends for soil maps. 4th edition. International Union of Soil Sciences (IUSS), Vienna, Austria. https://wrb.isric.org/files/WRB_fourth_edition_2022-12-18.pdf

[brownag]

Related qualifiers are character strings currently separated with a "/". This might make re-use of this part of the dataset difficult. I was thinking it would be good to keep track of the related qualifiers this way, but probably need a separate column for grouping and only one qualifier name per record in qualifier name column