# What is a Vector Graphic?

M.R. Anglin

A vector graphic is a type of a computer graphics that uses mathematical relationships between points on an image to describe that image. Vector graphics are more flexible and clear than raster, or bitmap, graphics, which are computer images that are made up of individual colored dots called pixels. There are a limited number of pixels in raster images, which means that a larger image needs more pixels and a smaller image fewer pixels. A vector graphic does not have that limitation because can be reduced or enlarged easily, based on the mathematical relationships between points “A” and “B." The mathematical relationship between the points is depicted as a path, or the line or curve that connects the two points.

Clarity, no matter the size, is one of the advantages of a vector graphic. Since a raster image, also known as a bitmap image, uses a limited amount of pixels to make up a picture, it cannot usually be enlarged without a loss of clarity. For example, if an image with 100 pixels needs to be enlarged to one with 1,000 pixels, the computer will have to add information in order to fill up the 900 extra pixels, often resulting in loss of clarity. Vector graphics do not have this limitation. Since a vector graphic uses math to express the relationship between two points in paths, enlarging and reducing the picture will not usually result in a loss of clarity.

This clarity often makes a vector graphic ideal for use in typeface, line art, and illustrations. As a business logo, for example, a vector graphic’s size can be decreased to be printed on letterheads and envelops, and can be enlarged for billboards with no loss of quality. Vector graphics are usually small files because the math describing the image is the only thing that needs to be stored. In addition, different people can edit the picture using the appropriate software by simply moving the dots around, which changes the path between the dots. These advantages allow it to be used in applications such as business logos, page layouts, fonts, and text art, among other uses.

Unfortunately, vector graphics are not usually ideal for photographic pictures. These details are often reserved for raster images. A vector graphic can be rasterized, however, which means it can be converted to a raster image by assigning pixels to the image, rather than using mathematical relationahips to describe it. A raster image can also be converted into a vector image, but it usually takes more work to make a clean vector graphic. Once rasterized, a vector image — now a raster image — can be edited as a regular raster image.

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Vincenzo

@Markerrag -- and the Internet has simply made that problem worse. Some people don't understand that an image that looks great on the Internet might not look so hot when it is printed on paper, a tee shirt or something else. The thing about Internet graphics is that they are compressed and made small so that pages will load faster. They are great for speed, but tiny raster graphics don't reproduce well at all.

It is a shame that vector graphics have to be simple. It would be great if photos could be converted to vector and manipulated, but we're not quite there yet.

Markerrag

@Soulfox -- you said it. Just ask any graphics artist about the kind of small, raster graphics that get sent to them and how hard it is to get a usable, professional image from them.

Here is a great trick for corporate logos and other simple items that are sent as small, raster graphics. There are plenty of packages out there that will convert them to vector so they can be scaled up quite large and still look great. That little trick can be just the thing a designer needs if he or she gets a logo that is too small to use and the client doesn't have a larger one available.

Soulfox

Graphic artists who don't work with vector graphics had better do some homework. Those are becoming more and more common for simple images because it is easy to make a small file and ship it all over.

The problem with raster images has everything to do with resolution. Let's say you've got a corporate logo that looks great on a tee shirt or scaled down to fit a letterhead? That is all well and good, but people run into trouble if they want to use it on a billboard unless the image is huge to begin with.

Vector graphics solve those problems. What is interesting is that vector graphics have been around for a long time but they are probably more popular now than they have ever been thanks to the scalability and portability of them.