NodeMatlab Plot


This node executes a snippet/script using a local Matlab desktop instance to produce a plot (graph). The Matlab script can be coded manually or templates can be selected from a snippet template repository. Templates can be used as such or they can be modified to the users liking.

RGG (R GUI Generator) is used to configure the Matlab code using a graphical user interface in a way that the user does not need to know scripting in Matlab.

Script Editor:
Copy, cut or paste and Matlab code to the editor and/or select the columns from your data table. If a template is loaded used the GUI to adapt the script to the input data.

Select a plot template from the template repository (double-click or "Use this template") to use that script and see the GUI. The description shows you an example plot than can be done using this template. Then configure the GUI according to your input data.

Output Options:
Specify the image dimensions of the plot and the type and location where to save that image.

This node needs a Matlab installation on the local machine!
If Matlab is not running, the node launches an instance of the Matlab desktop. It is recommended to let KNIME launch Matlab. The node can detect open Matlab instances, but this is not foolproof.


  • Snippet input variable name: kIn
  • Snippet output variable name: mOut
  • Supported Matlab types: dataset, table, struct or container.Map
  • While the script input type is defined by the preferences, the output type will be inferred from the output variable
  • The column names for dataset and table Matlab data types are taken from the object properties (VariableDescriptions/VarDesription). For the other types, they will be the same as the input as long as the header does not change.
  • Templates repositories are controlled via the preferences (Menu > KNIME > Preferences > KNIME > Matlab Scripting).

Further reading:
Further documentation can be found on the wiki.
To understand how to use flow variables in the script, please consult RGG XML.

Input Ports

  1. Port Type: Data
    A table which should be visualized with Matlab.

Output Ports

  1. Port Type: Image
    The generated Matlab plot as image column