Up to now, the subset selection for transit lines allowed only to select either all lines, lines corresponding to a given subset of transit modes, or a selection by line names. This old selection mechanism has now been replaced by a new one, which is very similar to the subset selection for nodes and links. It allows selecting subsets of lines by using multiple criteria which may involve all available transit line attributes by the use of associated keywords. Individual criteria can be complemented using the special operator not, and can be combined using the special logical operators and, or, and xor. Special operators are also provided to list existing transit lines and to display those lines that are currently selected. The following example shows the selection of all lines with mode b, and not vehicle type 2, which have a headway between 12 and 13 minutes:
Enter: Selected transit lines or attributes (from, to)
=mod=b
=and not veh=2
=?
Current set contains 55 lines, selected by:
1: mod=b
2: &!veh=2
=and hdwy=12,13
Continue line selection:
=&??___
line 12 : crescent
line 33 : mcgregor-academy
line 34 : mcgregor-stafford
Current set contains 3 lines, selected by:
1: mod=b
2: &!veh=2
3: & hdw=12,13
Continue line selection:
=
Besides the usual line attributes, an index variable is also available. It refers to a consecutive numbering of the lines in the order in which they are stored in the data bank (i.e. sorted according to the line names). This is very useful in macros, when a certain operation has to be performed on all lines. Without having access to this index variable, the macro would have to know explicitly the names of all transit lines, in order to select one line after the other. With the index variable, on the other hand, it suffices to set as a counter one of the registers x, y or z, and to increment its value by one at each step, until all lines have been treated.
Refer to section III-5.2.3 of the User Manual for a detailed description of the new transit line dialog.