On runlength-based approaches for achieving high-speed compression of map images

Many low bit-depth images, like map images, are more compactly expressed in terms of runlength-representations. Some image formats can utilize such representations to speed up image compression. It will be shown that both image standards basing compression on context formation, like JPEG2000, and standards performing compression scanline by scanline, like PNG, can utilize runlength-based optimisations. GIF is used as an example where runlength-based optimisations already have been established