When using the graph layout package, you need to determine which of
the ready-to-use layout algorithms is appropriate for your
particular needs. Some layout algorithms can handle a wide range of
graphs. Others are designed for particular classes of graphs and
give poor results or reject graphs that do not belong to these
classes. For example, a Tree Layout algorithm is designed for tree graphs, but not cyclic graphs. Therefore, it is important to
lay out a graph using the appropriate layout algorithm.
The following tables can help you determine
which of the layout algorithms is best suited for a particular type
of graph.
- Across the top of the table are various classifications of different types of graphs.
- The layout algorithms appear in the first column of the tables.
- Table cells containing illustrations indicate when a layout algorithm is applicable for a particular type of graph.
By identifying the general characteristics
of the graph you want to lay out, you can see from the tables
whether a layout algorithm is suited for that particular type of
graph.
For example, if you know that the structure
of the graph is a tree, you can look at the column headed
Domain-independent graphs to see which layout algorithms are
appropriate. The Uniform Length Edges Layout, Tree Layout, and
Hierarchical Layout could all be used. Use the illustrations in the
table cells to help you further narrow your choice.
You can use the Recursive
layout to control the layout of nested graphs (containing
subgraphs and intergraph links). This is useful in particular if
different layout styles should be applied to different subgraphs.
The other layout algorithms, such as Tree Layout and Hierarchical
Layout treat only flat graphs (unless otherwise noted); that is,
a specific layout instance is only able to lay out the nodes and
links of the attached graph, but not the nodes and links of its
subgraphs. Recursive Layout allows you to specify which flat
layout is used for which subgraph; it traverses the entire nested
graph recursively when applying the layout. As a result, the
entire nested graph is laid out.
You can use the Multiple
layout to combine several different layouts into one instance.
In this case, they become sublayouts
of the Multiple Layout instance.
This is useful in particular for nested
graphs when used in combination with Recursive Layout. Multiple
Layout ensures that the normal layout, the routing of the
intergraph links, and the layout of labels are applied in the
correct order to a nested graph.
Layout algorithms and common types of
graphs
Layout |
Domain-independent graphs | |||
|---|---|---|---|---|
Trees
|
Cyclic
Graphs |
Any
Graph |
||
Topological
Mesh Layout |
|
Requires (semi)manual refinements |
||
Uniform
Length Edges Layout |
|
Preferable to avoid heavily
interconnected graphs (large number of links) |
|
|
Tree
Layout |
|
|
||
Hierarchical
Layout |
|
|
|
|
Link
Layout |
|
|||
Grid
Layout |
The algorithm does not take into
account the links between the nodes. |
|||
Recursive
Layout |
Nested
graphs. |
|||
Multiple
Layout |
Combination
of multiple different layout algorithms on the same graph (in
particular for nested graphs). |
|||
Telecom-oriented representations
Layout
|
Telecom-oriented
representations |
|---|---|
Bus
Layout |
For bus topologies. |
Circular
Layout |
For interconnected ring/star
topologies. |