Graph elements

The following is a complete list of the visual elements, including nodes (vertices) and edges, that can be encountered in a process graph.

Vertices

Name	Visual	Description
Resource		An input or output resource.
Atomic Process		An atomic process.
Composite Process		A composite process.
Copy node		A process with a single input and multiple parallel outputs of the same type is assumed to be a copy process that makes multiple copies of its input.
Join node		A special node used when the output of a composite process does not have a single or clear source.
Merge node		A special node used when an optional input/output combines resources from multiple component processes.

Edges

Edges can be solid or dashed as shown below:

one solid and one dashed grey arrow pointing to the right

Dashed edges are used to indicate that the corresponding resource (or group of resources) is optional, i.e. part of an optional tree of resources where only one of the branches can be provided.