I work as a civil engineer in a paperless office. I have to deal with a lot of construction plans and for me it is important to be able to take measurements from those plans or draw in exact measurements. So I would be very pleased if a ruler, which can be set to a certain scale (e.g. 1:50) could be added to GoodNotes. Currently I have to resort to a pdf-software on my PC, which disrupts the workflow.