text: Hierarchies Many data sets, such as spatial entities of countries or common structures for governments, can be organized into natural hierarchies.  Node-link diagrams, adjacency diagrams, and enclosure diagrams are all types of infographics that effectively communicate hierarchical data. Node-link diagrams are a popular method due to the tidy and space-efficient results. A node-link diagram is similar to a tree, where each node branches off into multiple sub-sections. An alternative is adjacency diagrams, which is a space-filling variant of the node-link diagram.  Instead of drawing a link between hierarchies, nodes are drawn as solid areas with sub-sections inside of each section. This method allows for size to be easily represented than in the node-link diagrams. Enclosure diagrams are also a space-filling visualization method. However, they use containment rather than adjacency to represent the hierarchy. Similar to the adjacency diagram, the size of the node is easily represented in this model.
  Networks
  Network visualization explores relationships, such as friendships and cliques. Three common types are force-directed layout, arc diagrams, and matrix view. Force-directed layouts are a common and intuitive approach to network layout. In this system, nodes are similar to charged particles, which repel each other. Links are used to pull related nodes together. Arc diagrams are one-dimensional layouts of nodes with circular arcs linking each node. When used properly, with good order in nodes, cliques and bridges are easily identified in this layout. Alternatively, mathematicians and computer scientists more often use matrix views. Each value has an (x,y) value in the matrix that corresponds to a node. By using color and saturation instead of text, values associated with the links can be perceived rapidly. While this method makes it hard to view the path of the nodes, there are no line crossings, which in a large and highly connected network can quickly become too cluttered.