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Track: Transportation, Logistics Planning
Stephen Perone
METRO
600 NE Grand Avenue
Portland, OR 97232-2736
Telephone: 503-797-1771
Fax: 503-797-1794
E-mail: perones@metro.dst.or.us
Using Dynamic Segmentation to Integrate Transportation Modeling Networks with GIS
Defining Issue: Merging transportation modeling data from software packages, such as EMME2 with ArcView and ARCINFO, can benefit many planning activities besides transportation. The data can be useful for planning and analysis of activities involving land use, air quality, nonmotorized transportation such as bicycle planning, emergency management, and so forth. GIS Solution: An ArcView extension allows an analyst to import and export transportation modeling data between EMME2's transportation modeling software and ArcView ArcInfo. Also, a supporting ArcInfo AML is used to implement a street route system on top of itself with an accompanying EMME2 linear event system representing the modeling network allowing sharing of data between the two systems. Background: Because transportation modeling networks are generally never identically matched to their true spatial form, merging data between the two systems can present numerous challenges. Besides the general mismatch of shape between the two networks,
modeling networks also contain links for centroids (to represent network loading points) and subnetworks for pedestrians or fixed guideway transit systems. Most transportation modeling software packages use a "sketch" network to perform multimodel assignments. While oftentimes quite detailed, these networks generally don't reflect the true shape of the street infrastructure. These packages use nodes and links to represent networks, not bothering with vertices to give an arc its shape. By adding more nodes to the modeling networks it is possible to "shape" the network to more closely resemble it true representation. However, this can also add to the burden of the assignment models without producing any better results. This technique overcomes these inherent problems. Software: M2View, an ArcView extension, was developed to translate data between ArcView ARCINFO and EMME2. AML was used to facilitate data transfer between a modeling network and base street network, such as TIGER, through the use of
dynamic segmentation. NOTE: Assuming ArcView Network Analyst supports the same dynamic segmentation processes used with ArcInfo the routine, will be included as an ArcView extension.
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