Raster and vector are used for storing and manipulating images and graphics data on a computer. All of the major CAD software and GIS (Geographic Information Systems) packages available today are primarily based on either of the two- raster or vector graphics.
A raster image uses a framework of colors known as pixels to represent images. A specific location and color value is assigned to each pixel. When editing objects or shapes, in a bitmap image, you edit pixels. Because, raster images are resolution dependent they tend to lose quality when enlarged. A raster image has pixels associated with it for all spatial locations, it is strictly limited by how big a spatial area it can represent. The total size of a two-dimensional raster image will increase by 4 times, when the spatial resolution is increased by 2 times as the number of pixels are also doubled in both X and Y dimensions.
How to overcome the problem of lose quality when enlarging the image? This is where raster to vector conversion need comes in! Vector images are generally made of lines and curves defined by mathematical objects called vectors. These vector points allow the computer to connect the dots using straight and curves lines and strokes. The vector file that is produced has no jaggedness, no loss in detail and can be printed at any resolution or any size. This vector images can be scaled up or down without any loss in quality. Vector data is geometrically and mathematically associated and comes in form of lines and points. Points are stored using the coordinates, such as a two-dimensional point is stored as (x, y).
Application areas for vector image formats include:
1.Company Logos
2.3D and CAD programs
3.Specialized text effects
4.GIS systems
5.Plumbing design and detailing
6.HVAC
7.Electrical Drawings
Advantages of using a vector image formats include:
1.Resolution independent
2.No jaggedness when enlarged
3.Smooth curves
4.Small file sizes