# New Graph

The world wide administrative data built into STEM is represented as a graph. It is also possible for users to create their own custom graphs using the new graph wizard. The New Graph wizard supports user creation of custom lattices based on a set of "Graph Generators". A graph generator is a pluggable component able to generate a graph (a collection of nodes and edges) either algorithmically or from an external file. Currently, we have implemented an abstract Lattice Graph Generator with a Square Lattice Implementation. A user can specify the size of the lattice as well as several options for how the nearest neighbor (Common Border) are organized. In the future we plan to also support creating a New Graph From File.A graph generator can also be used to create a collection of edges (or other graph components) that an be optionally added to another graph. To use this feature, begin by launching the new graph wizard.

Button to launch the New Graph Wizard

## Creating a Square Lattice Graph

This wizard makes it possible to study the propagation of a disease model on (for example) a simple lattice instead of the more complex geographical administrative divisions.

1) Click on New Graph

3) Click on TestSquareLattice

4) Specify the size of the lattice

5) Select from the options available how you want the nearest neighbor mixing edges to be organized

6) Click "Finished"

save your work at this point by hitting <ctrl>S

In the future we plan to also support creating a New Graph From File.

Figure 8. A disease spreading on a square lattice
Figure 7. The New Graph Wizard

## Creating a Graph of Migration Edges

Given an existing graph, another graph generator allows a user to create a graph of components that may be (optionally) added to the existing graph. For example, the Migration Edge Graph Generator will create a graph of migration edges. If these are then added to a model containing the original graph, migration of a population will be enabled. Migration edges are created for a specified population and, at the current time, with a single migration rate. If no location is specified, a migration edge is created for every physically adjacent region of node within a graph. If a location is specified, migration edges are created for every physically adjacent region the selected node contains. For example, give a graph of the United States, specifying California would create migration edges for every county in California. In the future we will provide a graphical editor to allow creation of specific edges.

Migration Edge Graph Generator