1. A method for providing coordinate geometry augmented reality for visualizing a 3D digital model in a real environment, the method comprising: capturing, using a camera of a mobile device, an image of a physical marker placed on or around a physical structure in the real environment, wherein the physical marker is placed at a predetermined set of coordinates, determined by surveying equipment, at or around a tie-in location for an unbuilt element to be added to the physical structure according to a design; analyzing, using a processor, the image of the physical marker to determine a supplemental digital model that represents the unbuilt element associated with a digital marker, which corresponds to the physical marker; retrieving, from data storage, a data file comprising the supplemental digital model associated with the digital marker and relation data between the supplemental digital model and the digital marker; providing, on a display screen of the mobile device, an augmented reality image comprising a real view of the physical structure seen through the camera in real-time, overlaid with the supplemental digital model in relation to the physical marker according to the relation data so that the supplemental digital model representing the unbuilt element is seen in a geometrically correct orientation with respect to the physical structure according to the design.