Zone Group Enhancements

The possibility of defining zone groups and ensembles is one of the important concepts that render EMME/2 the powerful and general planning tool it is.

With Release 8, many enhancements and improvements related to ensembles and zone groups are introduced, which will make their use even more attractive:

• The old limit of a maximum of 1000 groups per ensemble has been lifted. Group numbers can now range from 0 to 9999, making it possible to define arbitrary zone aggregations in a single ensemble even for large applications having more than 1000 zones.
• A description of up to 40 characters and a time stamp recording the time and date of the last modification is stored along with each zone group ensemble. With the description, the rather cryptic ensemble identifiers gX can be complemented by a textual information, which will also appear in the header of all reports referring to ensembles. As it is already the case with matrices and extra attributes, each time the contents of an ensemble is modified, its time stamp is updated and the user has the possibility of modifying the ensemble description.
• In addition to the traditional way of defining zones by the specification of the corresponding nodes, module 3.01 has been enhanced to also allow defining and listing groups by node. This alternate format, in which a node is specified along with the groups it belongs to, is particularly useful when group memberships are defined in the form of zone attributes.
• The groups of an ensemble can be listed or punched in terms of the groups of a second ensemble. This allows the logical mapping of one ensemble onto another, independently of the underlying zone numbering scheme.
• A new option has been added to the matrix calculator, module 3.21, in which the result of matrix expressions can be used to define zone group memberships. Given that the zone group information can also be accessed within the matrix expressions via ``gX(p)'' and ``gX(q)'', new zone groups can now easily be constructed from any existing matrix and zone group information. E.g, storing the result of the expression ``int(ga(p)/10)'' in the new ensemble gb will create new aggregated zone groups in which the last digit of the original group numbers are dropped.