Dot maps or dot distribution map (also known as dot density map) is a map type that uses a dot symbol to show the presence of a feature or phenomenon. Dot maps rely on a visual scatter to show spatial patterns.
The following are advantages of dot maps:
- If well constructed it shows the distribution and comparative densities
- It is easier to show variation in the distribution of a wide variety of commodities if it is presented using different colors.
- Dot maps are used to represent a wide range of items like population, the value of minerals, crops, and so forth
- They are very easy to construct compared to proportional circles
- It is very easy to compare the distribution of items considering the concentration of dots.
- It is easy to interpret by counting the number of dots multiplied by the dot value to get the total value of the given area
The following are disadvantages of dot maps :
- It is time consuming especially when marking dots on maps
- When the scale is small many dots are drawn which cause overcrowding and present difficult in counting them to get the actual value
- In case even distribution of dots is displayed on the map, false impression that the distribution is the same in represented area is perceived. This perception may be false
- Locating dots on map is to the certain extent a personal and subjective decision and two dot maps done by two people using the same data will rarely be identical
- Construction of dot maps involves tedious calculation especially when determining number of dots