Radius Indicator?

[hard night]

What is a radius indicator? The tutorial tells me to pay attention to its color when placing a farm but I don't know where to look.

[dry cedar]

they're all the dots on the floor, its the spots where you can place plots, you need to pay attention because if its on the brown (mud), you cant plant crops, and if its next to buildigns you cant place crops ofc where the building is