Abstract: The present application provides indexing methods and systems for indexing spatial data objects of a data space, and methods and systems for performing an operation on an index of spatial data. One of the methods includes: associating each spatial data object with one of a plurality of separations according to a size of the respective spatial data object; and mapping each spatial data object to an index key based on the separation with which the spatial data object is associated. The methods and systems for performing an operation on an index of spatial data can facilitate efficient selection or manipulation of the spatial data objects.