1. A method for analyzing elevation differences between at least a first and second three-dimensional images of a region of interest, the first and second three-dimensional images having been taken at different times, wherein the three-dimensional images are generated based on combining a plurality of two-dimensional images, and the three-dimensional images are stored as a plurality of pixels containing pixel data and X parallax information derived from the plurality of two dimensional images, the method comprising: registering the first and second three-dimensional images for the region of interest so that corresponding overlapping pixels are identified; on a pixel-by-pixel basis, comparing data for corresponding overlapping pixels of the registered first and second three-dimensional images; if compared pixel data is different outside of a predetermined tolerance, then flagging a difference; using the X parallax information, determining elevation differences between compared pixels; and based on determined elevation differences of compared pixels, determining elevation changes that have occurred in the region of interest over time.