1. A method of monitoring human activity using multiple sensors comprising: monitoring accelerations using an inertial sensor; identifying a user activity based on the accelerations; making a first estimation of a user activity statistic associated with the user activity based on the accelerations, the user activity statistic being one of: a distance traveled or a speed of travel; making a second estimation of the user activity statistic based on location information obtained by a location based sensor; and calculating the user activity statistic based on the first estimation and the second estimation, wherein the calculated user activity statistic is a result of a weighted combination of the first estimation and the second estimation.