Graphics Reference
In-Depth Information
"Ben", "Zoe", 3
"Tim", "Zoe", 2
Note the following conventions for CSV files for graph data:
•
Header row
—The top row of each file defines the name of data for
each column.
•
Node column
—The first column of the node file contains the unique
identifier for each node.
•
Link columns
—The first two columns of the link file contain the links.
In a directed graph, the first column indicates the source nodes, and the
second column indicates the destination nodes.
CSV files can be easily opened, edited, extended, and exported in many
programs, including spreadsheets and text editors. CSV files can be
problematic because there is no data quality enforced in their format. For
example, the authors have come across CSV files with embedded tabs,
extremely long fields, invalid numerical values, and so on.
GDF Files
The
GDF
file format began with a graph system called GUESS and is now
commonly used with the graph software Gephi. GDF is similar to CSV files;
however, both nodes and links are defined within the same file, and visual
attributes such as edge widths, node sizes, colors, shapes, visibility, or even
images can be defined in the file as well. The GDF file format is a good
format for people who manipulate their graph data with spreadsheets.
Following is an example using the simple e-mail data set:
EmailGraph.gdf:
nodedef> name VARCHAR, NumEmails DOUBLE, width DOUBLE,
Recency VARCHAR
'Ann',1,2048,'10/31/2014'
'Ben',4,7687,'12/09/2014'
'Tim',2,102,'11/18/2014'
'Zoe',3,4292,'12/09/2014'
edgedef> NodeA VARCHAR, NodeB VARCHAR, weight DOUBLE,
color VARCHAR
'Ann','Ben',1,'0,0,255'
'Ben','Tim',2,'0,255,0'
