In order to give an idea how Enif presents itself on the screen, a typical Enif window is shown in Figure 2. It shows the zonal productions and attractions colored according to the corresponding mode share of the auto mode.
The main part of the Enif window shows the current view of the network plane. Located above it, the tabbed mapper control dialogs are used to access the configurable parameters of the current plot configuration. At the left side of the window, the view controls can be used to change the current view or to send the current plot to the printer. A menu bar on the top gives access to the various available tools and options, and, finally, the status bar on the very bottom of the window is used to display transient messages.
Since one important goal of Enif is to remain 100% compatible with existing EMME/2 application data, the network structure is essentially given by EMME/2. However, the internal network representation is completely different from the one used in EMME/2 [2,3]. The access and interpretation of EMME/2 network data is completely encapsulated in a separate modular network I/O interface.
Internally all network elements are represented using a common base class. This allows the implementation of many functionalities in a uniform way, independent of the actual type of network elements. This includes functionalities such as data access, handling of network attributes, expression evaluation and the definition of sub-networks by element selection.
