When working with spatial/geographic data, Tableau has nine built-in functions: area, buffer, distance, intersects, makeline, makepoint, length, outline and shapetype. These functions relate to spatial objects such as points, lines, and polygons.
These functions fall into two categories: those that create spatial objects based on your specifications, and those that give information about existing spatial objects.
Four fit into the first category: makepoint, makeline, buffer, and outline. Makepoint takes latitude and longitude inputs and creates a spatial point object - two of which can then be inserted into makeline to create a spatial line object. Buffer takes a location (a point) and a distance, and creates a spatial polygon object, representing the 'buffer' around that post, with the distance as the buffers diameter. Outline converts a polygon input into a simple line, representing the outline of that polygon.
In the information category are five functions: distance, area, length, intersect, and shapetype. The first three output a numeric value, respectively measuring the distance between two points, the length of a line, and the area of a polygon, each in a specified unit. Outputs are geodetic, meaning they take into account the curvature of the Earth. Intersect gives a boolean output, saying whether a spatial object (point, line or polygon) overlaps with another polygon object. Shapetype takes a spatial object and returns the type of object as a string (e.g. "point").