Approaches for indexing and retrieving spatial data with a quadtree index in database management systems are described. In an embodiment, data objects are stored without decomposition within a linearized quadtree stored within a B-tree index. In another embodiment, a method determines an optimal execution plan for a spatial query by parsing it to determine a query type and geometry object associated with the query. The method tessellates the query object by recursively decomposing the quadtree blocks that cover it. Cost-based decomposition decisions are made by consulting a cost model furnished by the database management system to minimize the cost of the resulting index range plan on the B-tree storage. Thus, data-directed query decomposition enacted by the method results in the optimal cost index range plan for the current data distribution and system context. In another embodiment, a system identifies and displays an optimal index range plan in a user interface.