Heads-up digitizing is a third form of the manual redraw process where the paper drawing is first scanned into a raster image and then displayed on a computer screen. The drawing is redrawn into vector format using software that traces vector lines and arcs on top of the raster image background. The software normally pauses at intersecting lines and waits for the human operator to initiate a command based on the operator's cognitive decision. This method is called heads-up digitizing, tracing or overlaying. With a trained operator it can be faster than other manual redraw methods.