What is a filter list? A filter list contains a selection of plants that meet particular criteria (e.g., 'Perennials, red, flowering in Apr-May'). You can specify any selection of these criteria (filter criteria) that you wish. The filter criteria describe a description to which the filtered-out plants correspond. In the filter process, all the plants are evaluated with respect to the criteria, and, if in accordance, they are copied to the filter list. You can save lists created in this way on your hard disk and open them again from there.
Defining a selection of criteria. You can define your selection of criteria for a filter list in two different ways: either, very simply, using the 'Filter assistant' (which offers simplified query options), or by using the 'Low level filter', in which you define the filter criteria manually. The 'Low level filter' method is more complicated, but offers almost unlimited possibilities for combining and branching filter criteria. You can switch from one method to the other at any time, even while defining a filter list. Choose the filter method you wish to use by opening the Filter window using the command [File.New filter list] and checking one of the two boxes in the Filter window, i.e., 'Filter assistant' or 'Low level filter'.
Fig.: Choosing between the 'Filter assistant' and 'Low level filter'
In the 'Low level filter', it is possible to specify filter links such as filter blocks. For clarity, these links are not shown in the 'Filter assistant'. Note that not all criteria that are entered in the 'Low level filter', or that are modified there, can be adopted by the 'Filter assistant'. The 'Low level filter' is intended for more experienced program users. An easy and effective approach is to combine both filter methods: you create the basis of the filter using the 'Filter assistant', and then specify the query more exactly using the 'Low level filter'.
