This is Gary Gallagher and Edward Ayers giving the keynote address at the 2010 meeting of the Society of Civil War Historians in Richmond, Virginia. Dr. Ayers presents some outstanding maps graphically depicting data and demonstrating the power of digital history. There’s an excellent discussion at the end during the Q&A.
From the video description: “The Society of Civil War Historians opened their second biennial meeting with a keynote address by Edward Ayers and Gary Gallagher at the Richmond Marriott. Their presentation was called “Fighting and Freedom: United States Military Forces and the Geography of Emancipation.” First Professor Gallagher discussed “fighting and freedom.” Then Mr. Ayers used illustrations while he discussed “mapping the emancipation.” They then jointly answered questions. Professor Gallman, the conference program chair, moderated.”