One of KNIME's great features is that it allows you to set certain properties of the views in advance. So, you need not remember how you set them in one view and how it is set in another, you just have to connect them to the same table. This is a big step towards reproducible experimental results and figures with the ease of graphical configuration. Each property is applied to the rows based on column values, so changes in column values will affect (remove) the property and each kind of property is exclusive (a new node with the same kind of properties replaces the original property). When you want to reuse the properties in another place of the workflow, you can use the appender nodes.
The three supported properties are: color, size, and shape.
With the Color Manager node, you can set the color for different rows. The colors can be assigned either to a nominal or a numeric column.
In the case of the nominal columns, each value can have a different color. This can be useful when you want to compare the actual or the predicted labels/classes of the rows.
When you assign colors to the numeric columns, the color of the minimal and the maximal value (as it is available in the column specification: Lower Bound, Upper Bound) should be specified. The remaining shades are linearly computed.
The Color Appender node allows you to use the same color configuration for other tables. Be careful when there are values outside the domain. The nearest extreme value is used in case of numeric columns and the black color is used for nominal columns. It is also possible to set an incompatible format to the column, but in that case, it will not be used.
The size of the points can be really a good indicator of the nonvisible attributes. It allows you to have larger or smaller dots for the different data points in views. The size is computed by the Size Manager node as a function of the input from the minimal value to the maximal value, similar to the numeric color property. (Based on the domain bounds, outside them the nearest extreme is used.)
The following are the supported functions:
- LINEAR: It is a linear function between the bounds
- SQUARE_ROOT: It is useful when you want a less increase in the higher values, but want more details of the lower values
- LOGARITHMIC: It is ideal when there is large difference between the bounds and more details near the lower bound is interesting
- EXPONENTIAL: The exponential function will make even small differences large
The Size Appender allows you to use the same size configurations in different places of the workflow, even for other columns.
The last property you can set is the shape of the points. For this purpose, you have the Shape Manager node, which allows you to set the shape based on a nominal column's values. Together with the Color Manager, you can visualize both the predicted and the original class of the training dataset. This can give you a better idea when the data is not properly learned and clustered, and might give you ideas to improve the settings.
Similar to other properties, the Shape Appender can bring the shape configuration to other parts of a workflow.