GIS Files 1: Getting to grips with GIS

1.2: Introducing raster and vector (4)

Raster v Vector

Both types of data are very useful, but there are important differences â€“ the characteristics below are broad generalisations which do not necessarily apply in all circumstances.

Vector	Raster
relatively low data volume faster display can also store attributes less pleasing to the eye doesn't dictate how features should look in a GIS	relatively high data volume slower display has no attribute information more pleasing to the eye inherently stores how features should look in a GIS

The image displays a simple comparison between vector and raster. What do you notice about the images as you zoom in and out?

In this example the raster data looks nicer but, as you zoom in, the pixel structure becomes obvious. Eventually the image looks like a piece of modern art rather than a detail of a map! The definition of the features is dependent upon the size of the individual grid cells â€“ the resolution. The vector data is more like a graph with a line drawn between points, the width staying the same however close you zoom.

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