Veronica Poplawski has posted a nice blog essay on Topic Modeling and Gephi: A Work in Progress : Digital Environmental Humanities. She walks through a project she did on 358 Environmental Humanities documents related to a workshop I was part of in the Fall (see my conference report here.) First she used Mallet to generate topics and then she created an XML file to bring the topics and associated words into Gephi for visualization. Nice work!