Phasor measurement units (PMUs) are beginning to be deployed widely in the power system, which gives system controllers the ability to directly measure phase angles. However, at present PMUs are only deployed at a small percentage of buses. This presents a challenge: how to get useful information from the small number of data points. This paper discusses work that has been done on visualizing the new data provided by PMUs. The paper begins by introducing the problems associated with visualizing PMU data in a wide area sense. It continues by discussing the application of equivalent circuit theory to arrive at equivalent injections. Next, difference contours are introduced as a way to alert operators to important changes without a cluttered display. Then, these ideas are applied to a large example system. Finally, conclusions and future work are discussed.