1. A method for detecting a change in a field of view from a first point in time to a second point in time, the method comprising: receiving, at a mobile unit in real time, current imaging data at a first point of reference on a travel route from a stereo pair of imaging receivers mounted on the mobile unit traveling along the travel route; generating, by the processor of the mobile unit in real time, a current three-dimensional dataset of the field of view from the first point of reference based on the current imaging data; determining a location of the first point of reference based on geo-spatial data; accessing a stored three-dimensional dataset of the field of view at the mobile unit, wherein the stored three-dimensional dataset is generated from imaging data previously captured at a second point of reference, and wherein the current three-dimensional dataset has a resolution lower than the resolution of the stored three-dimensional dataset; comparing, by the processor of the mobile unit, the current three-dimensional dataset of the field of view to the stored three-dimensional dataset of the field of view; identifying, by the processor of the mobile unit, the change in the field of view based on the comparison; and providing one or more alerts signifying the change in the field of view between the current three-dimensional dataset and the stored three-dimensional dataset.