Final answer:
The main difference between heat maps and tree maps is that heat maps utilize color variations to represent numerical data on a 2D surface while tree maps use nested rectangles to display hierarchical data with size proportions.
Step-by-step explanation:
The biggest difference between heat maps and tree maps lies in the type of data they are used to represent and the method of visualization. Heat maps are graphical representations of data where individual values contained in a matrix are represented as colors. They are often used to show the variation in data across a two-dimensional surface, where colors can indicate, for example, the intensity or density of a particular phenomenon, such as population density or temperature fluctuations.
On the other hand, tree maps are a method for displaying hierarchical data by using nested rectangles, where each branch of the hierarchy is given a rectangle, which is then tiled with smaller rectangles representing sub-branches. A tree map can be used to represent data such as disk space usage or organizational structures where the size of the rectangle is proportional to some numerical value, making tree maps useful for comparing proportions within the hierarchy.
In summary, heat maps focus on representing continuous numerical data through color variations across a two-dimensional space, whereas tree maps are suited for visualizing hierarchical data in a proportionally structured manner through the size of nested rectangles.