Graph(*) below provides an overview of main GITM fortran files. The branches represent dependencies. Nodes represent files. See the html source and the code page for details. Click and drag the node out of the way as needed.
Or, alternatively, you could put it in a different layout (somehow this is not working interactiely, so go here for a version where you can mouseover and see the connections):
(*) This applet is a modified version of mbostock's code (which is an application of Data-Driven Documents (D3)). This page is a work in progress, but you can see the code by right clicking and selecting View Page Source.