Читать книгу Statistical Approaches for Hidden Variables in Ecology - Nathalie Peyrard - Страница 34

The recorded data for the boobies were provided in the form of latitude and longitude measurements, that is, in terms of angles with respect to an origin point on the Earth’s surface. The methods presented earlier use a notion of distance (such as step length). While it is possible to calculate distances traveled over the Earth’s surface using latitude and longitude coordinates, this requires the use of specific formulas for movement on a sphere. Instead, data are often projected onto a plane, enabling the use of Euclidean distance. Due to the spherical nature of the globe, the actual projection used depends on the zone of interest². In this case, projection is carried out using UTM coordinates for zone 25 – south. In R, the sf library may be used to facilitate geographical data processing (and, notably, projection).