In a proper design, the sprinklers are placed so that the spray patterns overlap by as much as 50 percent to ensure even coverage. The sprinkler manufacturer can recommend how much the patterns should overlap. A slow precipitation rate applies water very slowly and is ideal for sloping lawns or areas where the soil absorbs water slowly. The controller is really the timer system, which tells the control valves when to open and close. Controllers are usually solid-state with electronic components.
Controllers are safe and easy to install.
A controller really makes your life easier because it can Water different parts of your lawn on different days and times. Water only the lawn and not the trees and shrubs. Water early in the morning before you get up. Water for a short period, shut off to let the water soak in, and then water again. Water more in hot summer weather than in cool spring weather.