Launch

Start directly with the "Assistant for Thematic Maps"".

Select type

Select "Pie" and click Next

Layer & Data Fields

Select the layer "Cables" and add the data field "Usage".

Note: Only number fields are offered!

Now click on Expression to define a formula.

Formula

Define a formula for the difference between the load and 100.

Click OK

Click Next.

Define styles

Remove the "Graduated" check mark. All cake digrams are displayed with the same size.

Now define a color for each piece of cake.

Value Usage

Value 100-Usage

Size of the pie chart

Position of the pie chart

Label

Switch to the "Legend" tab.