1. Visualization
   1. Know your network
   2. Five principles
      1. Show the data
      2. Maximize data-in ratio
      3. Erase non-data ink
      4. Erase redundant data-ink
      5. Revise and edit
   3. In practice
      1. What is interesting in the data
         1. Geography
         2. Communities
         3. Special significan nodes
      2. Criteria
         1. Minimize edge crossing
         2. Uniform edge lengths
         3. Avoid nodes overlap
      3. The smaller and the sparser
2. Metrics
   1. Degree
      1. Edges
         1. Directed
            1. indegree
            2. Non 0 entries
            3. On a given column
            4. Sum
            5. Outdegree
            6. Non 0 entries
            7. On a given row
            8. Sum
         2. Undirected
            1. How many edges are incident on a node
      2. Examples
         1. Who is the most popular?
         2. Coauthoring
      3. Centrality
         1. Examples
            1. Who your friends are
            2. Quality friends
            3. Well connected friends
         2. Inmediate network
      4. Degree sequence
         1. Degree of each node
         2. Degree distribution
   2. Other attributes
      1. Weight
         1. Possitive
         2. Negative
      2. Ranking
      3. Type
      4. Graph structure
   3. Is everything connected?
      1. Overall connectivity of the network
      2. Is everyone reacheble?
      3. Sparse
      4. Connected components
         1. Directed networks
            1. Strongly connected components
            2. Weakly connected components
         2. Undirected networks
            1. Connected components
      5. Giant component
         1. Significant portion of the graph
3. Data representation
   1. Adjacency matrix
      1. Outgoing edges
      2. Positions
         1. Rows
         2. Columns
         3. nr. of Node
      3. Values
         1. Aij=1 ->i has an edge to j
         2. Aij=0 -> i has no edge to j
         3. Aij=Aji reciprocy
         4. Aii=0 unless self-loops
            1. Diagonal=0
   2. Edgelist
      1. Edges to
   3. Adjacency list