This function sets the geographical extents used in global analysis. See also geoscale_param() to set the geographic extent of an analysis that is not global.
Each geographic extent should be in the form of c(Xmin, Xmax, Ymin, Ymax). Geographic extent must be specified by four values in degrees that represent the geographic limits of the area for analysis, following the order: minimum longitude, maximum longitude, minimum latitude, and maximum latitude. Degrees are in decimal notation and have a negative sign for the southern and western hemispheres.