However, needing to pan around the screen in order to view the map causes a new sensation in perception and effectiveness of the map. The alternatives are making the file size smaller, thereby reducing the quality of the image and making it unusable because of illegible cartographic marks. This reduces the load time, but breaks apart the map, which was intended to be viewed as one unit. When file sizes are too large or a map image needs touch up, tools are available to alter the image. Ideally, a reduction in file size would not have a subsequent result in reduced image quality.
Quality here is defined as legibility of text, distinguishing colors, and legibility of fine lines.
Compression options, such as lossless GIF and lossy JPEG, were used by the Oversized Color Images Project with varying success. Color images remained quite large. A second processing tool are arithmetic algorithms which actually reduce the amount of data. Using a GIS, the operator can generalize the map by using a data point reduction algorithm. Eliminating data points is necessary when the scan produces a rough line instead of the desired clean line.