1. Choropleth Maps

3. Definition
Maps where areas are shaded according to a prearranged key, and each shading colour represents a range of values.

4. Advantages Useful at any scale, from global to local
The data can be used in many different ways at many different levels of analysis, from general overall patterns to the detection of details.
Helpful for finding intriguing hot spots,
Detecting relationships between the encoded variable and geographic location (and the many variables entangled with location), or
Comparisons between areas.

5. Disadvantages
They give a false impression of abrupt change at the boundaries of shaded units.
Choropleths are often not suitable for showing total values.
It can be difficult to distinguish between different shades.

6. Volunteering Rates Across NSW