An observation is an assertion that an entity (e.g., biological organisms, geographic locations, or environmental features, among others) was observed by an observer. An observation primarily serves to group a set of measurements together into a single "observation event". Observations are often made within a broader context. The context of an observation is given by other observations, implying that an observed entity (and specifically each corresponding measurement) contextualizes another observed entity (and its corresponding measurements). For example, an observation associated with a location may serve as context for an observation associated with an organism. In this case, the observed characteristic values of the location (such as humidity) are assumed constant for the corresponding measurements of the organism.