The Surface Deformation Prediction System (SDPS) program has been developed as an engineering tool for the prediction of subsidence deformation indices through the implementation of an influence function. SDPS provides reliable predictions of mining induced surface displacements, strains, and tilt for varying surface topography. One of the key aspects in obtaining reliable ground deformation prediction is the determination of the edge effect offset. The value assigned to the edge effect corresponds to a virtual offsetting of boundary lines delineating the extracted panel to allow for roof cantilevering over the mined out area. The objective of this thesis is to describe the methods implemented in updating the edge effect offset algorithm within SDPS. Using known geometric equations, the newly developed algorithm provides a more robust calculation of the offset boundary line of the extracted panel for simplistic and complex mining geometries. Assuming that an extracted panel is represented by a closed polyline, the new edge offset algorithm calculates a polyline offset into the extracted panel by the user defined edge effect offset distance. Surface deformations are then calculated using this adjusted panel geometry. The MATLAB® program was utilized for development and testing of the new edge effect offset feature.