  In this paper, we propose the mqr-tree, a two-dimensional spatial access
method that organizes spatial objects in a two-dimensional node and based on
their spatial relationships. Previously proposed spatial access methods that
attempt to maintain spatial relationships between objects in their structures
are limited in their incorporation of existing one-dimensional spatial access
methods, or have lower space utilization in its nodes, and higher tree height,
overcoverage and overlap than is necessary. The mqr-tree utilizes a node
organization, set of spatial relationship rules and insertion strategy in order
to gain significant improvements in overlap and overcoverage. In addition,
other desirable properties are identified as a result of the chosen node
organization and insertion strategies. In particular, zero overlap is achieved
when the mqr-tree is used to index point data. A comparison of the mqr-tree
insertion strategy versus the R-tree shows significant improvements in overlap
and overcoverage, with comparable space utilization. In addition, a comparison
of region searching shows that the mqr-tree achieves a lower number of disk
accesses in many cases
