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 This
section explains the differences between Bitmap-based
image files and Vector-based
image files.
All image files
can be categorized into two kinds, Bitmap-based
and Vector-based files.
The two differ in the way computers analyze their content.
Vector-based
images generally contain well-defined elements such as curves and
shapes of various colors. These elements can either be pure graphics,
western alphabets or Asian characters. Each element is defined mathematically
by the computer. For example, if a vector-based image contains a
red dot, then information such as the location of the circle's center
point, the length of its radius, and the color, red, would be the
essential information for this image file.
File names
for vector-based images usually consist of extensions such as *.EPS,
*.AI, *CDR, or *.DWG.
Vector-based
files are more suitable for illustrations that require precise measurements.
They are also easily scalable due to their mathematical nature.
However, the vector-based file format has its drawbacks as well.
It is not good for displaying photo-realistic images such as a photograph
because images of this type generally do not contain well-defined
shapes and curves.
Bitmap-based
images, on the other hand, do not rely on mathematical formulas
to define their various elements. Each bitmap-based image is mapped
into a grid. The size of the grid is based on the image's resolution.
For example, a bitmap-based image of 1 inch x 1 inch with a 600
dpi resolution would be defined by a grid of 600 x 600 pixels. Hence,
a bitmap-based image is like a mosaic of pixels with each pixel
holding a specific color value.
Bitmap-based
files are more suitable for photo-realistic images that require
complex color variations. They are, however, not easily scalable
because each bitmap-based image is mapped to a non-flexible grid.
If a bitmap-based image were to be enlarged, it would lose its sharpness.
All edges within the image would appear to be jagged.
File names
for bitmap-based images usually consist of extensions such as *.PSD,
*.JPG, *GIF, *.TIF, or *.BMP.
In general,
bitmap-based files require more computer memory for file storage
than vector-based files. The former contains all information for
every single pixel of the image while the latter contains only the
defining mathematical formulas for each element within the image.
For
more information on image file format click here.
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