1. A computer-implemented method, comprising: identifying, from an index structure stored in memory, a reference minimum bounding shape that encloses two or more minimum bounding shapes, each of the two or more minimum bounding shapes corresponding to a data object associated with a corresponding leaf node of the index structure; and compressing the index structure using the reference minimum bounding shape, the compressing including representing at least one minimum bounding shape of the two or more minimum bounding shapes in a relative representation calculated relative to the reference minimum bounding shape, the representing including associating coordinates of a corresponding point of one or more points of the at least one minimum bounding shape with a first value comprising a first number of significant bits fewer than a second number of significant bits representing a second value associated with absolute coordinates of the corresponding point, the first value being calculated relative to coordinates of a reference point of the reference minimum bounding shape.