A bounding box is a rectangle that defines the spatial extent and position of a geometric object or area in two-dimensional space. It encloses geometries such as points, polygons, and line segments. section 10.6
Geospatial indexes store bounding boxes rather than complete coordinates or shapes. During a search, the database quickly identifies boxes within or intersecting a target area and skips unrelated geometries. section 10.6
GiST uses bounding boxes hierarchically:
- Groups geometries into large boxes, recursively splits them into smaller boxes, and reaches leaf boxes containing references to the actual geometries. section 10.6
- SP-GiST divides space into non-overlapping quadrant boxes around selected centroids, then subdivides those quadrants. section 10.6
