The amount of groundwater exploited is estimated in m³/year. Groundwater usages are classified in four categories: agricultural, industrial, domestic and energy. Typically, groundwater usage should be represented as a series of sub-polygons or points fitting inside the boundary of the hydrogeological unit. The scope and method used to estimate the amount of water are described in the metadata associated with the dataset. The dataset identifies the main usages for the hydrogeological unit. It features numbers and percentages describing groundwater usages for a predetermined scope. The groundwater usage is frequently compiled by municipalities or counties. It could then be possible to display the usage by superimposing a series of pie charts depicting the groundwater usages over multiples administrative areas.