Open toolkit for systems modelling


Diagramming languages

A Systo "diagramming language" defines the types of nodes and arcs needed for a particular class of diagram. For example, the system_dynamics language defines 'stock', 'valve' and 'variable' nodes, and 'flow' and 'influence' arcs.

See the language gallery for an example of a model diagram for each Systo language hosted on this site.

Name Description Nodes Arcs
system_dynamics System Dynamics (stock-and-flow) diagramming.
stock - an amount of some substance (e.g. water, carbon...)
variable - a model parameter or intermediate ("auxilliary") variable
valve - a flow rate (always attached to a flow arrow)
cloud - a stock whose value is of no interest (automatically created when dragging a flow to/from the canvas)
flow - a "pipe" between stocks and/or clouds
influence - a link showing that one variable is used to calculate another
biological_pathway A basic language for representing biological reactions.
species - a chemical "species" (element or compound) involved in a reaction
catalyst - a substance which influences a reaction but is not consumed by it
reaction - an actual reaction
stoichiometry - the stoichiometric value of a 'reactant' or 'product' link (always attached to one or other of these arcs)
reactantthe link from a species into a reaction
productthe link from a reaction into a species
modifierthe link from a catalyst to a reaction
wcs_conceptual_modelling An informal language used by various conservation organisations (including WCS - the Wildlife Conservation Society) for mapping the threats to a target species, and the measures that can be taken to counteract these threats.
goal - the overall goal of a conservation project
target - the target species to be conserved
direct_threat - direct threats to this species
indirect_threat - indirect threats to this species
intervention - intervention measures that managers can take
link - a generalised connection between any of the above nodes