permanent storage for example a flash memory or a hard drive may store program instructions for execution by the processor the controller unit 11 can be co located with other units for example with the sensor unit 10 or with the steerable water delivery system 12 alternatively the controller unit 11 can be located in a separate place away from the other units the irrigation system is also provided with the time of the day and its location for example through providing it with the correct latitude and longitude or through its street address from which its latitude and longitude can be determined using this information the system is able to determine the time of day and the location of the sun in the sky to improve the processing of its sensor data and especially to correct for harsh shadows the system may use detection of sharp shadows to aid determination of the slopes and dips of the planted area as the shadow shape sweeps across the area under a normal operating mode the system continually or repeatedly takes images of the planted area and processes the images to determine what locations in the planted area need watering or other types of care the system can then direct its nozzle to the locations in need of water fertilizers or pest control solutions the system may perform image preprocessing before vegetation detection is performed for example the system may perform image geometry.