Comparison Between Raster and Vector

Comparison Between Raster and Vector

Often the question arises: what should be used raster of vector format? We hope the following comparison between the two systems gives you some common information about this question.

Raster – image formed as a sum of pixels. At present it is a dominating method of resulted presentation of graphic information (on raster displays and printers). Also it is used a close notion of bit map (bitmap) – raster saved on memory or disk. The raster image feature is in fact that size of uncompressed file and consequently the loading rate are independent of image complexity. The advantage of raster is a simple method and therefore rapid way of the image bit plane representation on the raster imaging devices or viewers. The limitation of this type of image is in fact that it can’t be intentionally scaled because the decreasing of image size may lead to loss of some pixel rows, but increasing accompanied with enlargement of pixel sizes. Raster type of image is useful for pictorial graphics storage, at the same time quite effective shrinking algorithms have been developed for storage of raster data.

Vector – image formed with aid of separate lines, straight or curved. Quality of vector imaging is due to an accuracy output (it is demanded the devices supported vector imaging plotters or vector displays) and nomenclature of supported basic graphic primitives (lines, arches, curves, ellipses, etc.). The main advantage of vector graphic is a scaling convenience with possibility of working on the details of elements of different sizes on the one image. Besides, the advantage of vector graphic is in the fact that a form, spatial location and color of objects describe by mathematical formulas. It provides comparatively small sizes of image file and independence of resolution of print device or display. For representation of vector image it is usually demanded quite complicated software that understands and correctly carries out all nontrivial protocols of drawing commands saved in file of vector graphic format. At the same time the more complicate image is the larger size of respective file and the longer time the image drawing takes.

Vector image has a range of advantages over raster drawing. The main advantages are:

  • possibility of accurate creating and description of object;
  • possibility of scaling and editing of object without loss the image quality.

Vectorisation – conversion from raster image to vector representation. In the most cases this operation involves loss of information about separate image elements which the program can’t correctly describe (mainly quantity of curves is intentionally minimized). Respectively reverse operation is raterisation. Technically this operation is simpler than vectorisation, but we lose possibility of intentional scaling of created image.