First Advisor

Ric Vrana

Term of Graduation

Winter 2000

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Geography






Trauma centers -- Oregon -- Portland Metropolitan Area, Emergency medical services -- Oregon -- Portland Metropolitan Area, Geographic information systems -- Oregon -- Portland Metropolitan Area



Physical Description

1 online resource (vi, 77 pages)


The allocation of trauma patients to one of two trauma centers based on multiple criteria presents significant challenges in modeling network-based solutions for Emergency Medical Services (EMS). Capabilities in a desktop Geographic Information Systems (GIS) include spatial analysis and map visualizations that contribute to improved understanding of EMS and the trauma allocation. Using a common desktop GIS application and a statistical analysis application, key spatial and temporal characteristics of both penetrating and blunt trauma are described, and the EMS allocation system is analyzed.

As a sub-group of all emergencies, trauma-system patients represent the most severely injured. Understanding the spatial-temporal distributions of traumas are paramount in the planning and management of such a system. Concentrations of trauma vary widely over the study area. The highest concentrations are not necessarily associated with the highest residential population densities.

The two-center system is highly balanced in terms of both overall allocation and in type of trauma. Average travel times to each center are nearly equal overall. However, analysis shows there is no correlation between predicted and observed travel times.

Spatial modeling of address-matched trauma calls, discriminating by the nature of the trauma (penetrating or blunt), shows that penetrating traumas are concentrated in certain hours of the day (peaking around midnight) and in certain areas of the region, with highest concentrations in and near Oldtown and close-in Northeast neighborhoods. Blunt traumas also demonstrated varying concentrations with clustering in the Downtown and Old Town areas, but were more related to the street network and traffic along arterials.


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