Vector vs. Bitmap

What exactly is a bitmap? Why is it different than a vector graphic? What is 'rasterization'? This post will help clear up some confusion about these digital formats.

Vector Graphics (SVG)

Scalable Vector Graphics (SVG) or more commonly 'vectors' are digital images that use mathematical and geometric formulas to control how the image is displayed on a computer screen. Basically a vector graphic uses points and curves instead of pixels when rendering an image. The advantage of vector graphics are that they can be scaled down or up to any size desired without loosing any integrity or producing artifacts like seen in raster images. Vector graphics can only be created and resized in programs that support it. Common programs include Adobe Illustrator and Inkscape.

Use of Vector Programs:

• Create an image to be viewed and printed at different sizes. (Bussiness logos, Website banners)
• Create a poster or other large scale image to print for smooth crisp edges.
• Create a 3D image. (MAYA, 3ds Max)
• Create sprites for flash animations.

Some Vector File Formats:

• .svg
• .ai - Adobe Illustrator
• .pdf (If created using a vector program)
• .cdr - CorelDRAW
• .odg - OpenOffice Spreadsheet
• .swf - Shockwave/Adobe Flash

Bitmap/Raster Graphics

Bitmap/Raster images are based on pixels rather than mathematical or geometric formula. Because bitmaps are based on pixels, they cannot be scaled without loss of integrity. Remember when you last zoomed in on a .jpg image it just looks like a bunch of squares? That is because the image is made of squares originally formed by pixels on a grid. When the image is displayed at 100% it may be hard to see because the pixels are small, but when scaled up to 400% it is easy to see. This shows that resizing an image does not rasterize (pixelate) an originally lossless image, but rather it has always been like that. I like to compare it to a painting, when viewed at a close distance you can see the brush strokes and small nuances, but when viewed stepping back a considerable amount you just notice the image painted and not the small details and marks.

Use of Bitmap/Raster programs:

• Edit bitmap images. (Adobe Photoshop)
• Create images to be viewed at one size. (Digital paintings)
• Scan and save document files for quick and easy use.

Some Bitmap/Raster File Formats:

• .jpg or .jpeg
• .png
• .tiff or .tif
• .gif
• .bmp
• .RAW

Useful Links and Additional Information:

http://en.wikipedia.org/wiki/Vector_graphics

http://en.wikipedia.org/wiki/Raster_graphics

http://en.wikipedia.org/wiki/Image_file_formats

http://www.webopedia.com/TERM/V/vector_graphics.html

http://www.webopedia.com/TERM/B/bit_mapped_graphics.html