# 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

At times it is interesting to study the propagation of a disease model on a simple lattice instead of the more complex geograhical administrative divisions. STEM now supports user creation of custom lattices via the New Graph wizard, shown in the Figure below. The wizard makes use of "Graph Generators," a new concept. A graph generator is a pluggable component that is 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. To create a custom square lattice:

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