1. A method of defining a region of interest in a construction document, the method comprising: accessing a stored construction document from a non-transient computer-readable memory, the construction document including a graphical representation of structures included in a building plan; displaying at least a portion of the construction document on a display; receiving an input from a user, the input identifying a point within the region of interest; defining a perimeter of the region of interest by identifying a boundary of the region of interest; identifying one or more notations along the boundary, wherein the one or more notations are protrusions from the boundary and include information about structures in the construction document; determining whether the one or more notations (i) represents part of the perimeter of the region of interest, or (ii) represents a protrusion that is not part of the perimeter; wherein determining whether a first notation from the one or more notations represents part of the perimeter of the region of interest includes determining a contour distance associated with the first notation, wherein the contour distance includes a distance of a line forming an outer boundary of the first notation; determining a straight line distance associated with the first notation, wherein the straight line distance is a distance of a line connecting two points along the boundary of the region of interest that removes the first notation from the boundary; and determining a ratio of the contour distance to the straight line distance, wherein the first notation is determined to be part of the perimeter or not part of the perimeter based on the ratio; adjusting the perimeter of the region of interest by including the notations determined to be part of the perimeter of the region of interest and by bypassing the protrusion that is not part of the perimeter to omit the protrusion from the perimeter; and calculating, by a processor, a quantity associated with the region of interest based on the adjusted perimeter of the region of interest.