Bitmap vs. vector

QUESTION: What is the difference between a bitmap graphic format and a vector graphic format?

ANSWER: The terms "bitmap" and "vector" refer to the two basic methods of describing graphics digitally.

A bitmap description describes a graphic as a grid with thousands or millions of dots.

(Another word for bitmap is raster.)

In the simplest kind of bitmap description, some of the pixels are "on" (black) and some of them are "off" (white). Things get a little more complicated when you are talking about a color graphic as opposed to a black-and-white graphic, but the principle is the same.

A very simple bitmap description of a rectangle outlined in black might look something like this:

Each digit "1" represents a pixel that is black, and each digit "0" (zero) represents a pixel that is white.

GIF, TIFF, JPEG and BMP files are all bitmap-format files. Some applications that can create bitmap-format files are Adobe Photoshop, Windows Paint, and Windows Paint 3D.

A vector description uses a programming language to describe a graphic in geometric terms. For example, a vector description of a square might say: "At a point three inches in from the left edge of the paper and four inches up from the bottom edge of the paper, draw a rectangle four inches wide and two inches tall and outline it with a line 1/4 inch wide." In programming language, this vector description might look something like the following:

HPGL files and CAD files are vector-format files. Some applications that can create vector-format files are AutoCAD, Adobe Illustrator, and CorelDRAW.

Some types of files can be bitmap-format files, vector-format files, or both. For example, an EPS file or a PDF file can contain descriptions of text and graphics in both bitmap format and vector format.

See also What is raterization?