Earth observation can be defined as the collection of information about physical, chemical or biological systems using remote sensing technologies such as satellite sensors or airborne instruments, but complemented by field observations and other recording techniques. Earth observation is used in the agricultural sector because it can assess and visualise over time and at multiple scales, usually using indicators, crop processes and properties. These indicators are derived through modelling processes, using data from sensors, field measurements and records describing farming activities at farm level. These models need to be tested over time in order to make the necessary corrections and check their adequacy for the specific crop type, variety, soil type and microclimate conditions.