A Global Transformation for Generating an Orthoimage

This paper introduces a new approach for generating an orthoimage known as Global Transformation. This transformation relies on a polynomial function and specific factors such as a building's height and density of tie points. A modified form of polynomial is first considered and is subsequently applied for selected control points from a digital surface model and an aerial photograph. Then, the polynomial model of these control points is established. During the process of transformation, all pixels of an aerial photograph are transferred to a digital surface model with a positional accuracy of 2 and 8 pixels at control points and tie points, respectively. However, when height and density of tie points are included in the transformation, the accuracy increases to 1 and 2 pixels at control points and tie points, respectively.