1. Members’ geographic distribution
of Infectious diseases network

2. Targets
• Locate EIN members’ geographic locations (in
Zipcode level)
• Find the potential coverage of each EIN member
location by Thiessen method1
• Add new member location iteratively to calculate
potential coverage and weight index of each EIN
member location by Greedy Adding Algorithm2
(GRIA)
• Rank potintial new member location by the
weight index
• Identify locations in order of the index (to be
considered for recruit new members)

3. Locations of members of EIN

4. Locations of members of EIN and Population
based on Primary Care Service Area (PCSA) for
main continent Member counts
Population by PCSA
0 250 500 1000
miles

5. Notes
1:Thiessen (Voronoi) polygons define individual areas of
influence around each of a set of points. Thiessen
polygons are polygons whose boundaries define the
area that is closest to each point relative to all other
points. They are mathematically defined by the
perpendicular bisectors of the lines between all points
2:A greedy algorithm repeatedly executes a procedure
which tries to maximize the return based on examining
local conditions, with the hope that the outcome will lead
to a desired outcome for the global problem. In some
cases such a strategy is guaranteed to offer optimal
solutions, and in some other cases it may provide a
compromise that produces acceptable approximations.

6. Notes
1:Thiessen (Voronoi) polygons define individual areas of
influence around each of a set of points. Thiessen
polygons are polygons whose boundaries define the
area that is closest to each point relative to all other
points. They are mathematically defined by the
perpendicular bisectors of the lines between all points
2:A greedy algorithm repeatedly executes a procedure
which tries to maximize the return based on examining
local conditions, with the hope that the outcome will lead
to a desired outcome for the global problem. In some
cases such a strategy is guaranteed to offer optimal
solutions, and in some other cases it may provide a
compromise that produces acceptable approximations.