Web Data Visualization

9.2 Summary

In this chapter, we have motivated the need for the data visualization operators and introduced some operators such as web nest, web unnest, web coalesce, web expand, web pack, web unpack, and web sort that provide different flavors of visualizing web tables. The web nest and web coalesce operators are similar in nature. Both of these operators concatenate a set of web tuples over identical nodes and produce a set of directed graphs as output. The web pack and web sort operations produce a web table as output. The web pack operator enables us to group web tuples based on the domain name or host name of the instances of a specified node type identifier or the keyword set in these nodes. A web sort, on the other hand, sorts web tuples based on the total number of nodes or total number of local, global, or interior links in each tuple. Web unnest, web expand, and web unpack, however, perform the inverse functions of web nest, web coalesce, and web pack, respectively.