Spatiotemporal
Database Models and
Languages For
Moving Objects
A Review
Content
 Motivation
 Spatiotemporal Concepts
 Spatiotemporal Data Models
 Spatiotemporal Query Languages
 Open Issues...
Motivation
 Increasing availability of mobility data
 Existing applications of mobile data
 vehicle trajectories optimi...
Motivation [2]
 Current Geographic Information Systems (GIS)
 conceived to process traditional, static or slow
changing,...
Content
 Motivation
 Spatiotemporal Concepts
 Spatiotemporal Data Models
 Spatiotemporal Query Languages
 Open Issues...
Spatiotemporal Concepts
 Space: framework to formalize specific relationships
among a set of objects
 Spatial data refer...
Conceptual models of space
 Set-based space
 relationships: element/set equality, subset, union,
etc.
 Topological spac...
Modelling approach
 Spatial data models
 continuous: abstract model
 discrete: suitable for relational DBMS
 Field-bas...
Spatial data types
 4 basic abstract data types (Güting et al. , 2000)
 a point is a point in the Euclidean plan
 a poi...
Spatiotemporal data types
 To capture time, Güting et al. (2000) defined two
other basic abstract data types:
 mpoint = ...
Moving Objects (MO)
 Pervasive object that changes position or extend
continuously (Güting et al., 2000):
 trajectory = ...
Dynamic attributes
 Prasad Sistla et al. (1997) classified attributes of
object-class databases as being static or dynami...
Content
 Motivation
 Spatiotemporal Concepts
 Spatiotemporal Data Models
 Spatiotemporal Query Languages
 Open Issues...
Spatiotemporal data models
 Generic spatiotemporal data models were proposed
since early 1990’s
 Worboys et al. (1990) p...
Spatiotemporal data models for MO
 MO means continuously changing data
 MO position and extend could change quickly
 Re...
Spatiotemporal data models for MO [2]
 Sistla et al. (1997) proposed the Moving Objects
SpatioTemporal (MOST) data model
...
Spatiotemporal data models for MO [2]
 Praing and Schneider (2007) proposed the Future
Movements of Moving Objects (FuMMO...
Content
 Motivation
 Spatiotemporal Concepts
 Spatiotemporal Data Models
 Spatiotemporal Query Languages
 Open Issues...
Spatiotemporal query languages
 Spatiotemporal queries are difficult to express using
a usual query language (e.g. SQL)
...
Content
 Motivation
 Spatiotemporal Concepts
 Spatiotemporal Data Models
 Spatiotemporal Query Languages
 Open Issues...
Open Issues
 Dynamic attributes are not yet implemented in
existing data models and query languages:
 track real-time MO...
2010-06-17CISTI.2010@jps 22
Spatiotemporal Database
Models and Languages For
Moving Objects
A Review
Thank You
Joaquim P. ...
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Spatiotemporal Database Models and Languages For Moving Objects - A Review

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A short review about spatiotemporal Database Models and Languages For Moving Objects

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  • Set-based spaces formalize the relationships between elements, sets and membership, such as element‑equality, set‑equality, subset, union, etc. The set-based space model is the foundation of object‑relational databases.
  • Abstract modelling is conceptually clean and simple, but discrete modelling is closer to implementation
  • Spatiotemporal Database Models and Languages For Moving Objects - A Review

    1. 1. Spatiotemporal Database Models and Languages For Moving Objects A Review
    2. 2. Content  Motivation  Spatiotemporal Concepts  Spatiotemporal Data Models  Spatiotemporal Query Languages  Open Issues 2010-06-17CISTI.2010@jps 2
    3. 3. Motivation  Increasing availability of mobility data  Existing applications of mobile data  vehicle trajectories optimization  leisure purposes  location-based systems, …  New applications are expected to emerge  to find mobility patterns of people  to track animals movements  or any kind of moving objects (MO) 2010-06-17 3 CISTI.2010@jps
    4. 4. Motivation [2]  Current Geographic Information Systems (GIS)  conceived to process traditional, static or slow changing, geospatial data  are not suitable to support the MO dynamism  The Database Management Systems (DBMS) market leaders support spatial data applications  However, modern relational DBMS:  are not designed to run spatiotemporal queries  context or semantic issues cannot be considered in the storage process 2010-06-17 4 CISTI.2010@jps
    5. 5. Content  Motivation  Spatiotemporal Concepts  Spatiotemporal Data Models  Spatiotemporal Query Languages  Open Issues 2010-06-17CISTI.2010@jps 5
    6. 6. Spatiotemporal Concepts  Space: framework to formalize specific relationships among a set of objects  Spatial data refers to the  position of objects and the  space occupied by them  Spatiotemporal: spatial data + time dimension.  Most research about spatiotemporal data concerns 2D + T:  2 space dimensions (2D)  time dimension 2010-06-17CISTI.2010@jps 6
    7. 7. Conceptual models of space  Set-based space  relationships: element/set equality, subset, union, etc.  Topological space  relationships: boundary, interior, open, closed, within, connected, and overlaps  Network space  relationships: connectivity among nodes  Euclidean space  transforms spatial properties and relationships in coordinates 2010-06-17CISTI.2010@jps 7
    8. 8. Modelling approach  Spatial data models  continuous: abstract model  discrete: suitable for relational DBMS  Field-based discrete data models  spatial data: collection of spatial functions  Transform space-partition (e.g. raster) to attribute domain (height, rainfall, temp., etc.)  Object-oriented discrete data models  spatial data: collection of discrete, identifiable, spatially referenced entities  The objects are independent of their location 2010-06-17CISTI.2010@jps 8
    9. 9. Spatial data types  4 basic abstract data types (Güting et al. , 2000)  a point is a point in the Euclidean plan  a points value is a finite set of points  a line is a finite set of continuous curves  a region is a finite set of disjoint parts/faces  Discrete data models  Implemented in current GIS as field-based (raster) or object-based representations (vector).  Basic data types: point, line and polygon  To define the polygon, Worboys et al. (1990) added: node, chain and ring. 2010-06-17CISTI.2010@jps 9
    10. 10. Spatiotemporal data types  To capture time, Güting et al. (2000) defined two other basic abstract data types:  mpoint = time  point  mregion = time  region  and a closed system of operations was defined  Based in the fact that abstract models are impossible to implement, Forlizzi et al. (2000) proposed the discrete data types:  ureal  upoint, upoints  Uline,  uregion 2010-06-17CISTI.2010@jps 10
    11. 11. Moving Objects (MO)  Pervasive object that changes position or extend continuously (Güting et al., 2000):  trajectory = moving(point)  line  The trajectory of a MO  the data refers to the past, but  can be useful to get current position and  predict future movements 2010-06-17CISTI.2010@jps 11 (Praing & Schneider, 2007)
    12. 12. Dynamic attributes  Prasad Sistla et al. (1997) classified attributes of object-class databases as being static or dynamic  The static attribute (common database attribute)  needs explicit update to change its value  The dynamic attribute  changes continuously as a function of time  does not require to be explicitly updated  defined by three sub-attributes:  the value  the update time  a time function 2010-06-17CISTI.2010@jps 12
    13. 13. Content  Motivation  Spatiotemporal Concepts  Spatiotemporal Data Models  Spatiotemporal Query Languages  Open Issues 2010-06-17CISTI.2010@jps 13
    14. 14. Spatiotemporal data models  Generic spatiotemporal data models were proposed since early 1990’s  Worboys et al. (1990) proposed an OO design methodology to design GIS  Shekhar et al. (1997) proposed a GIS Entity Relational model (GISER)  continuous fields are associated with discretisation and interpolation models. 2010-06-17CISTI.2010@jps 14
    15. 15. Spatiotemporal data models for MO  MO means continuously changing data  MO position and extend could change quickly  Requires high data update frequency, which could cause performance problems to DBMS  MO database should store predicted data and provide query capability for querying such data 2010-06-17CISTI.2010@jps 15 (Praing and Schneider, 2007)
    16. 16. Spatiotemporal data models for MO [2]  Sistla et al. (1997) proposed the Moving Objects SpatioTemporal (MOST) data model  designed to handle dynamic attributes  to reduce the update frequency  the result of a query will change on time, even if the database is not updated  The project Databases fOr MovIng Objects tracking (DOMINO) had 4 requirements (Wolfson et al., 1999):  location modelling of MO  query language for spatiotemporal data  index of continuously changing data  handle the uncertainly of MO query results. 2010-06-17CISTI.2010@jps 16
    17. 17. Spatiotemporal data models for MO [2]  Praing and Schneider (2007) proposed the Future Movements of Moving Objects (FuMMO) abstract model:  to define the future movement of MO, such as points, lines or regions  considering future evolutionary properties, such as uncertainty and dimensional restrictions. 2010-06-17CISTI.2010@jps 17
    18. 18. Content  Motivation  Spatiotemporal Concepts  Spatiotemporal Data Models  Spatiotemporal Query Languages  Open Issues 2010-06-17CISTI.2010@jps 18
    19. 19. Spatiotemporal query languages  Spatiotemporal queries are difficult to express using a usual query language (e.g. SQL)  Typical queries: MO position or trajectory  Several extensions to SQL were proposed  The Future Temporal Logic (FTL) language allows querying future states of the modelled system  designed to be executed on the top of native DBMS query language (DOMINO Project)  queries are based on two basic future temporal operators: until and nexttime 2010-06-17CISTI.2010@jps 19
    20. 20. Content  Motivation  Spatiotemporal Concepts  Spatiotemporal Data Models  Spatiotemporal Query Languages  Open Issues 2010-06-17CISTI.2010@jps 20
    21. 21. Open Issues  Dynamic attributes are not yet implemented in existing data models and query languages:  track real-time MO position  predict future movement of objects  Uncertainly constraints should be taken in account by data models and languages  Context or semantic issues can cause performance problems to query current DBMS  Need to extend the data models & languages:  4 dimensional applications (3D space + time)  indoor environments (space constraints) 2010-06-17CISTI.2010@jps 21
    22. 22. 2010-06-17CISTI.2010@jps 22 Spatiotemporal Database Models and Languages For Moving Objects A Review Thank You Joaquim P. Silva School of Technology IPCA, Barcelos, Portugal jpsilva@ipca.pt

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