1. A method for determining a scale used in estimating a path of a computing device in motion, the method comprising: receiving a plurality of pairs of points along the path based on inertial sensor data from the computer device; determining which of the plurality of pairs of points along the path are constrained, each constrained pair of points comprising a first point and a second point, the first point being associated with a first constraint having a first radius, the second point being associated with a second constraint having a second radius, the first point and the second point being separated by a distance; determining for each constrained pair of points a first bound and a second bound based on the first radius, the second radius, and the distance; determining a first intersection of the first bounds of the plurality of pairs of points and a second intersection of the second bounds of the plurality of pairs of points; and setting the scale as an intersection of the first intersection and the second intersection.