Walking a neighborhood, study subjects wear a Galvanic Skin Response (GSR), which is a simple indicator of the emotional arousal in conjunction with their geographical location.
Z. Toups, A. Kerne, W. Hamilton, and N. Shahzad. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 1959--1968. New York, NY, USA, ACM, (2011)