GIS Files 1: Getting to grips with GIS

1.5: The significance of scale (2)

Scale of capture

All GIS packages enable you to zoom in and out on the map data as much as you like. Again, this means that you cannot say that the map data has a particular scale. However, all topographic data has a scale of capture – that is the source data was captured at a particular scale, whether this was a paper map or an aerial photo.

It is important to understand the source scale of your data for two fundamental reasons:

1. Data from a particular scale should only be viewed within a certain range of magnification for it to make sense visually.

2. Combining two or more datasets together is only appropriate if they have an equivalent scale of capture.

< 1.5: The significance of scale (1) | 1.5: The significance of scale (3) >