Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for characterization of a physical site. One of the methods includes obtaining, for each of one or more physical locations corresponding to a respective coordinate at a surface of a growing medium at the locations, sensor data comprising a sensor profile generated from measurements taken by each of a plurality of sensors on a sensor unit passing through the respective coordinate at a plurality of different depth levels within the growing medium at the location; providing the sensor data as input to one or more probabilistic models configured to receive the sensor data comprising the respective sensor profiles to predict one or more characteristics of the growing medium at each of the physical locations; and obtaining, as output from the one or more probabilistic models, the one or more predicted characteristics for each physical location.