Scales and Maps

Scales and Maps

A scale on a map is the relationship between the physical object and the feature that represents it on a map.  An example of this would be the length of a road on the ground and the way that the road is represented on a map. 

Image 1: The road on the left could be identified as the Upper Glen Road on the right in the Map. 

If, for example, the length of a road is 1cm on a map and it measures 2500cm (or 0.025km) on the ground, the scale of the map is 1:2500.This would be called a large scale map as it can be represented as a very large fraction i.e. 1/2500.  A smaller scale map would be 1:450,000 as its fraction is much smaller 1/450,000.  1cm on this map would represent 4.5km on the ground. 

If two cakes were divided up which of the following slices would you prefer to eat because it is large. 

Cake A is divided into 3 pieces and cake B is divided into 15 pieces. 

If you wished to get a large slice of cake then a slice from Cake A would be the best option.  This is because 1/3 is a larger fraction than 1/15.  Using this kind of thinking it makes sense to call maps with a large scale fraction large scale maps and the maps with small fractions are then naturally called small scale maps.  Large scale maps also contain more map detail than the small scale map. 

The small scale map contains less detail than a large scale map.  The small scale maps contains a summary of the detail found in a large scale map.  For instance the centre of a town on a small scale map would be coloured in a complete grey block to represent all the buildings in the area whereas the large scale map would have distinct outlines of the buildings.  Also the avenues and minor roads to residential dwellings may be left out of a small scale map. 

The small scale map above shows the town of Killarney and the surrounding area.  It is an ideal map for somebody who wants to travel through and outside the town.  However if you wanted to stop off at a known location, like a train station, in the town the large scale map would give a more precise information as to the name of the street it is on etc. 

As can be seen from the layout above the town of Killarney is displayed in large scale. 
The large scale map looks very hard to read as it contains an awful lot of detail and information.  Large scale is best for concentrating on a small area like Killarney.  Once zoomed into the map the level of detail can be appreciated. 

This type of map would be ideal if you wanted to see how to get from High Street to the train station.  So, it is a good scale map to use if you wanted to have a lot of detail for a local neighbourhood.  Imagine what this large scale map would look like if you showed the entire country of Ireland at once!  It would be messy!  There would be too much information and the map features, like the Estate-Names and the outlines of each house, would overlap on top of each other. 

In review small scale maps are ideal for showing a summary of map detail for a vast area whereas the opposite can be said for large scale data. 

It is important to note the following:

Large fraction=”large” scale=”covering” a small area. 
Small fraction=”small” scale=”covering” a large area.