Abstract: A system that allows the remote measurement of the size, geometry, pitch and orientation of the roof sections of a building and then uses the information to provide an estimate to repair or replace the roof, or to install equipment thereon. The system includes an aerial image file database that shows aerial images of buildings in a designated area according to address. The slope and orientation images are typically oblique perspective views and top plan views of the buildings in the area. The system also includes an image analysis and calibration feature that enables the viewer to closely estimate the size, geometry and orientation of the building's roof sections. The information can then be used to prepare a cost estimate for the repair or replacement of the roof or installation of roof equipment.