Network data restructuring is an essential function in Geographic Information
Systems (GIS) when adapted to transportation. Implementing effective data
restructuring models in GIS allows users to collect and maintain data in the format
with which they are most familiar while allowing others to utilize it in a format they
requ ire. Aggregation and disaggregation of network data facilitates storage, display
and plotting times. There could however be important adverse effects. The effects of
generalizing attribute data for aggregation/disaggregation is being researched here.
Milepoint referenced data in road inventory files provides valuable network
information for transportation research. Individual records in these files represent
variable length sections of roads. A new record is created each time a highway
attribute changes. Consequently, a segment of road between two intersections may
be represented by several records in a road inventory file. Further, all attributes in
these records are associated with both directions of travel along a road.
Many transportation analysis models requ ire networks to be represented by a
node-link structure where nodes symbolize an intersection of two or more roads.
Further, if a road is two directional, it is represented by two links each of which has
its own set of attributes. To utilize road inventory data in these analysis models,
network information has to be converted into an intersection/link format. This process involves aggregating· and disaggregating attribute data to represent longer and
shorter road segments and also disaggregating data into bi-directional information.
This thesis describes data conversion efforts needed to produce intersectionllink
network representations. The development of a microcomputer model for data
conversion is detailed and application issues and model sensitivities are addressed.
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