ABSTRACT
Because points, lines and areas are so different from one another, the type of queries they are used for and hence the algorithms developed for them are sometimes different. Some queries are just not meaningful for all vector types. For example, polygons can contain points, but points cannot contain polygons, hence a point in a polygon test is useful, but a polygon in point test is not. Even when queries are meaningful for all types, they may need to work rather differently. For instance, it is possible to measure the distance between any two features. If both are points, this is simple, but if they are areas, then there are several possible distances: the distance between the nearest points on the boundaries, and the distance between the centroids.
