The theme 'type' is a string with one or more key words to define the theme type

There are two basic theme types:

• CHOROPLETH
• CHART

and different CHART types like PIE, BAR or SYMBOL and the class distributon mode like EQUIDISTANT, QUANTILE or LOGARITHMIC or CATEGORICAL for discrete value like 'type' or 'year'

• for single fields it is either a classification method like EQUIDISTANT, QUANTILE or LOGARITHMIC or CATEGORICAL for discrete value like 'type' or 'year'
• for multiple field charts it can be 'by field' (for bar or pie charts) or 'dominant' or 'significant', if we have single value charts or shapes for the visualisation

('significant' is a value that is most above its own mean value; measured in standard deviation)

Method to define the size of the chart objects by giving the value that should be represented by a 'normal' size of 30 screen pixel.

Higher values lead to smaller charts.

The range scale defines a factor to apply on yaxis compression or complex symbol radius.

• a value > 1 expands the chart/plot
• a value < 1 compresses the chart/plot

The size power defines a factor for a function which calculates the size from the value. Here some examples:

• 1 defines a linear relation between value and size
• 2 defines a relation between the surface of a symbol (circle, square, ...) and the value
• 3 defines a relation between the volume of a symbol (sfere, column,...) and the value
• 0.1 defines a log10 relation between the size and the value
• 0.2 defines a log10 relation between the surface and the value