This document summarizes a seminar on visualizing data presented by Professor Donna Gitter. It defines what data is, including numbers, dates, statistics, interviews, and photos. It discusses primary and secondary sources for collecting data and explains how to visualize data through charts, graphs, maps, timelines and infographics. Finally, it lists some tools for visualizing data, such as Excel, Dipity, Google Custom Maps, Social Explorer and infographic creation websites.