Transcript SpatioTemporal

Research Issues in Spatiotemporal Database Systems
Timos Sellis
Presented by
Handy Patriawan
Fall 2000
CS 599 – Spatial and Temporal Databases
Introduction
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Common techniques and tools
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R-Tree for both Spatial and Temporal
Join Spatial and Temporal into one
Proposed name: STDBMSs
 Spatio-temporal DBMSs
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Current application
Geographic Information Systems (GIS)
 Environmental Information System
 Multimedia
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Fall 2000
CS 599 – Spatial and Temporal Databases
Introduction (cont’d)
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Examples:
Fall 2000
CS 599 – Spatial and Temporal Databases
Introduction (cont’d)
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CHOROCHRONOS
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http://www.chorochronos.com
Issues to be addressed:
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Ontology, structure and representation of
space and time
Data model and query language
GUI
Query processing, storage and indexing
techniques
Architecture
Fall 2000
CS 599 – Spatial and Temporal Databases
Introduction (cont’d)
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Extension of Spatial or Temporal
DBMSs is not enough
Adding Temporal support to SDBMSs
 Adding Spatial support to TDBMSs
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Final frontier: unified Spatiotemporal DBMS
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Spatio-temporal data structures,
operators and user-interfaces
Fall 2000
CS 599 – Spatial and Temporal Databases
Issues…
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Ontological Issues
Ontology: the study or concern about what
kinds of things exist – what entity there are
in the universe (http://www.whatis.com)
 Including Structure and Representation
 Finding a common framework
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• E.g. common structure and representation
Fall 2000
CS 599 – Spatial and Temporal Databases
Issues…
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Ontological Issues (cont’d)
• Ontology of spatial entities: life and motion
Fall 2000
CS 599 – Spatial and Temporal Databases
Issues…
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Ontological Issues (cont’d)
• Spatial objects are located “somewhere” in
space
Region
Object
Part Location
Fall 2000
CS 599 – Spatial and Temporal Databases
Issues…
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Models and Languages for STDBMSs
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Focus on 3 topics:
• Language for spatio-temporal relations
• Models and languages for STDBMSs
• Design and techniques for STDBMSs
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Research is divided into 2 categories:
• Tight integration of spatial & temporal
• Adding spatial support to temporal
Fall 2000
CS 599 – Spatial and Temporal Databases
Issues…
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Different classes of applications
Events in space & time, Moving region,
etc.
 See [4] for more details
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Different data structures &
operations has been defined as well
(see [4])
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E.g. mpoint x mpoint -> mreal:distance
Fall 2000
CS 599 – Spatial and Temporal Databases
Issues…
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Constraint database models
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Development in spatio-temporal constraint-based
database model
Example: DEDALE
• Prototype of a constraint DBMS for spatio-temporal
information
• See http://www-rocq.inria.fr/verso/dedale/
• See http://sikkim.cnam.fr/dedale.html
• Still based on SQL
• Display the parts of roads which is inside the rectangle RECT
drawn on the screen
• Select SELECT(r.geometry, RECT)
From r in Roads
Where Satisfy(SELECT(r.geometry, RECT))
Fall 2000
CS 599 – Spatial and Temporal Databases
Issues…
Extending current SQL
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STSQL
Allowing relations to have attributes that are
spatial or temporal
Not intended for movement of continuously
moving or changing objects
Y
t=n
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t=n+1
t=n+2
CS 599 – Spatial and Temporal Databases
X
Proposed Indexing for
Moving Object
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“Indexing the Positions of Continuously Moving
Objects”
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Simonas Saltenis, Christian S. Jensen, Scott T.
Leutenegger and Mario A. Lopez
Issues: How can we index a moving object (and or
changing object) during time periods?
Proposed solution:
• R*-Tree with time as parameter (boring….)
• Function…
Fall 2000
CS 599 – Spatial and Temporal Databases
Function for Indexing
Moving Objects
Y=X
Y
Y=3
t=n+1
t=n
Fall 2000
Y=X-2
t=n+2
Time
Function
n
Y=X
n+1
Y=X-2
n+2
Y=3
CS 599 – Spatial and Temporal Databases
X
Storage, Indexing and
Querying
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Storage and Indexing:
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Support for motion
Benchmarking
Indexing: R-Tree, Quadtree, etc.
Benchmark:
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Make sure to include everything needed
Test access method, data generation, query
processing and result analysis
---> Common platform for benchmarking the
STDBMS as a whole
Fall 2000
CS 599 – Spatial and Temporal Databases
Storage, Indexing and
Querying
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Query processing and optimization:
Efficient access for spatial, temporal
and spatio-temporal
 Simple cost model for query
optimization
 Study of spatial and temporal
constraint database
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Fall 2000
CS 599 – Spatial and Temporal Databases
Conclusion
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Good progress… still more work is
needed:
Devising clean and complete semantics
for data models and operators
 Efficient implementation
 Indexing and query optimization
 Alternatives architectures for building
STDBMSs
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Fall 2000
CS 599 – Spatial and Temporal Databases