Spatial Database Types of Spatial
in a multidimensional space
Raster data such as satellite imagery, where each pixel stores a measured value
Feature vectors extracted from text
have spatial extent with location and boundary.
typically uses geometric approximations constructed using line segments,
polygons, etc., called vector data.
Types of Spatial Queries
Ø Spatial Range Queries
all cities within 50 miles of Madison Query has associated region (location,
includes ovelapping or contained data regions
the 10 cities nearest to Madison Results must be ordered by proximity
Ø Spatial Join Queries
all cities near a lake
join condition involves regions and proximity
Applications of Spatial Data
Ø Geographic Information Systems (GIS)
ESRI‘s ArcInfo; OpenGIS Consortium
classes of spatial queries and data are common
spatial objects such as surface of airplane fuselage Range queries and spatial
join queries are common
Images, video, text, etc. stored and
retrieved by content First converted to feature vector form; high
dimensionality Nearest-neighbor queries are the most common
trees are fundamentally single-dimensional indexes.
we create a composite search key B+ tree, e.g., an index on <age, sal>,
we effectively linearize the 2-dimensional space since we sort entries first by
age and then by sal.
Consider entries: <11, 80>, <12, 10>
<12, 20>, <13, 75>