Definition
In the context of geographic information system (GIS), scale is an important term that depicts a mathematical relationship between a map's size and the size of the area it represents on the Earth's surface. Scale quantifies the relationship between distances on maps and the corresponding distances in the real-world, allowing users to calculate distances and areas of features or phenomena represented on the map.
The scale is often represented as a ratio, such as 1:1000, which means that one unit (such as an inch or centimeter) on the map represents 1000 of the same units in the actual world.
What is Scale?
Scale in GIS is fundamentally the degree of detail represented by the geographical data. In simpler terms, it is the degree to which a map 'zooms in' on geographic features.
There are two types of scales used in GIS: map scale and analysis scale. Map scale, as mentioned above, refers to the degree of reduction between the real-world and the map. Analysis scale, on the other hand, refers to the geographical area for which data is analyzed, such as the global, regional or local scale.
Scale is a critical concept in GIS because it impacts both the precision and accuracy of spatial data and analysis. The scale determines the level of detail in the collection, representation, and analysis of geospatial data.
FAQs
What are the different forms of scale representations in GIS?
The scale in GIS is generally represented in three ways: ratio or representative fraction (1:1000), verbal statement (one centimeter equals ten kilometers), and bar scale or graphical scale (a graphic that relates map distance to ground distance).
Why is the concept of scale important in GIS?
Scale is vital in GIS because it influences the level of detail of the information captured from the real world. Variables may look different and lead to different analytical results depending on the scale.
Does the scale affect the resolution of the geographic data?
Yes, the scale directly impacts the resolution of the geographic data. Larger scales contain more detail and have higher resolution, while smaller scales contain less detail and have lower resolution.
What is the impact of scale on spatial analysis?
The scale impacts the type and extent of spatial analysis that can be performed. For example, data at a local or property scale could be suitable for detailed engineering design, while data at a continental scale would be appropriate for broad environmental planning.
What is meant by "changing the scale" in GIS?
Changing the scale in GIS refers to altering the level of detail or geographical extent of the view or analysis. It could mean zooming in (increasing the scale) for more detail or zooming out (decreasing the scale) for a broader view.
