An apparatus and method for manipulating scanned documents using computer aided design (CAD) commands includes a link program which receives the CAD commands and displays all or selected portions of a raster-based image, which is created by scanning a hard copy document. The link program will display the portion of the raster image which fits within a predetermined CAD window and will scale the raster image up or down as necessary to fit within the display window. The raster image is displayed on a computer screen and provides a useful reference for an operator to create a CAD image which is a duplicate of the raster image by tracing directly over the raster image or, alternatively, to implement desired changes in the raster image using CAD commands. An edit program merges the CAD image and the original raster image to create a new, updated raster image, which includes all CAD-generated changes made by the operator. The updated raster image can be reproduced in hard copy form by a raster plotter.