For some of the monitoring data, the combination of options (monthly or yearly data, one or several locations, different categories like crop type and/or irrigation technology) make a rather complex pattern, and only certain combinations can be displayed in two-dimensional tables.
The possible combinations are shown the user in so-called table-options. They are displayed in list-boxes. The content is only descriptive, as the user has only the choice to select option no. 1, 2 etc. The content of the list boxes is stored in tables: