Figure 1 from: Mesibov R (2013) A specialist's audit of aggregated occurrence records. ZooKeys 293: 1-18. https://doi.org/10.3897/zookeys.293.5111

Figure 1 - Illustration of 'uncertainty', 'distance' and 'offset'. In MoA, spatial uncertainty is defined using the point-radius method, where a site is assumed to be at the centre of a circle whose radius is the uncertainty u. In both diagrams, d is the Euclidean distance between the MoA estimate of the site's location (blue cross) and the aggregator estimate (red square). The offset o is the distance d minus the uncertainty u. In diagram 1 the aggregator site is within the circle of uncertainty surrounding the MoA site, and the offset is negative. In diagram 2 the aggregator site is outside the circle of uncertainty and the offset is positive