Pigale: Open Source Software for Theoretical Graph Research

Pigale (Package for Interactive Graph Algorithms and Layout Engineering) is a specialized open-source software tool designed for the drawing and visualization of planar graphs. It provides a suite of linear-time algorithms to handle planar graph structures and is primarily used for research and application in graph drawing, particularly focusing on connectivity, planarity testing, and drawing methods like straight-line, orthogonal, or visibility representations. Core Features and Capabilities of Pigale

Planar Graph Specialization: Pigale excels in managing graphs that can be embedded in a plane without edge crossings.

Linear-Time Algorithms: Many tools in Pigale, such as those testing 3-connectivity or 4-connectivity in maximal planar graphs, operate in linear time, making them highly efficient.

Connectivity Testing: The software allows for testing if a planar graph is 3-connected, or if a maximal planar graph is 4-connected.

Special Orientations: It utilizes techniques based on special orientations, such as bipolar orientations, which are crucial for solving various graph drawing problems.

Graph Drawing Styles: Pigale provides tools to generate different types of planar drawings, including straight-line and orthogonal layouts, which are critical for visualization. Key Uses in Visualization and Drawing

3-Connectivity Testing: Pigale includes algorithms that can efficiently determine if a planar graph is 3-connected.

4-Connectivity Testing: For maximal planar graphs, the software offers a linear-time routine for checking 4-connectivity.

Visualization of Planar Embeddings: It supports the analysis of graphs by embedding them in the plane, which helps in studying properties like acyclicity and special orientations.

Pigale is notable in the field of graph drawing for its algorithmic efficiency and focus on planar, highly-connected structures. If you’d like, I can:

Compare Pigale to other graph visualization tools (e.g., Gephi, Cytoscape).

Explain the difference between planar and non-planar graph visualization. List other open-source tools used for graph visualization. PIGALE – Brown CS