The minimum bounding rectangle, also known as bounding box or envelope, is an expression of the maximum extents of a 2-dimensional object within its 2-D coordinate system, in other words min, max, min, max. The MBR is a 2-dimensional case of the minimum bounding box. MBRs are frequently used as an indication of the general position of a geographic feature or dataset, for either display, first-approximation spatial query, or spatial indexing purposes.