Development of a Data Exchange Protocol between EMME/2 and ArcInfo

  ich one to establish first depending on the objectives of the applications and timing considerations. In that case, one sees the importance of submitting guidelines to build one and the other.

Case four: Both the EMME/2 data bank and the ArcInfo workspace exist but have been built separately. This is the most complex case. The integration of these two networks can be done by using techniques such as rubber sheeting (stretching the coordinates of the elements of one network to match the elements of the other), conflation (aligning two coverages and transferring the attributes from one to the other), etc.

The modeling process represents the transformation of the user network in the master GIS into the EMME/2 coverage. This can be complex or simple depending on the design of the database. In order to create the EMME/2 coverage from an existing master GIS, the planner has to take a road network coverage and convert it into an aggregate representation by removing unnecessary details, merging some arcs together and reevaluating attributes. Also, if the transportation network includes a transit network, the planner has to take the route-system representing transit lines and split underlying arcs at bus stops to create a node. This process must include a procedure to keep the correspondence between the user network and the base network of the EMME/2 coverage. The modeling process is specific to the organization where it is implemented.

E) Data structure of the EMME/2 coverage

Figure 2 - Entity-Relationship Diagram
The EMME2.AAT table stores information related to the arcs of the EMME/2 coverage, and its definition follows the NETWORK data model of ArcInfo. This implies that, since one arc

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