The Architecture of a Flexible Querier for Spatio-Temporal Databases

1
The Architecture of a Flexible Querier for
Spatio-Temporal Databases
GeoInformation Group Image Processing Division
DPI

• Karine Reis Ferreira
• Lúbia Vinhas
• Gilberto Ribeiro de Queiroz
• Ricardo Cartaxo Modesto de Souza
• Gilberto Câmara

2
Introduction

• Challenge to GISystems use spatially enabled
  DBMS to build innovative applications which deal
  with spatio-temporal data
• How to address it
• ST Types and their associated Algebra (Gutting,
  2005)
• Conceptual models, E-R models for ST-Data
  (Pelekis et al, 2004)
• ST Query Languages (ISO, 2001)
• ST Predicates (Egenhofer and Franzosa, 1991
  Allen,1983)
• Which is the canonical set of ST Predicates?
• Application specialized subset
• Building blocks that can be combined (Erwig and
  Schneider, 2002)

3
Introduction

• How to design a flexible query processor for
  spatio-temporal data using object-relational
  DBMS?
• Some aspect to be considered
• Applications are different in terms of queries
  and responses
• An unified and flexible architecture is desired

4
Layers

• A geographical database is composed by layers
• Layers contain Spatio-Temporal Objects
  (ST-Objects)
• Static Layers
• ST-Objects do not change along the time, neither
  in their descriptive or geometrical attributes
• Temporal Layers
• ST-Objects change along the time, either in their
  descriptive or geometrical attributes
• ST-Instance represent version in a given time of
  a ST-Object

5
Database Model

• Ex a layer of districts of a city

layers layers
layerId int layerName string
1 Distritos
DistrictsG DistrictsG DistrictsG
geomId int objId string spatialD spatial
1 D1 bbbbbbbbbbbbb
2 D2 bbbbbbbbbbbbb
3 D3 bbbbbbbbbbbbb
representations representations
layerId int geomRelatio string
1 DistrictsG
DistrictsA DistrictsA DistrictsA
CODDIS string NOME string POP int
D1 Agua Rasa 85896
D2 Cangaiba 137442
D3 Capão Redondo 240793
attributesRel attributesRel
layerId int attrRelation string
1 DistrictsA
6
Database Model
Initial State
DistrictsG DistrictsG DistrictsG
geomId int objId string spatialD spatial
1 D1 bbbbbbbbbbbbb
2 D2 bbbbbbbbbbbbb
3 D3 bbbbbbbbbbbbb
DistrictsStatus DistrictsStatus DistrictsStatus
attrInst string geomInst string timeI time timeF time
1 1 01/01/2003
2 2 01/01/2003
3 3 01/01/2003
DistrictsA DistrictsA DistrictsA
CODDIS string NOME string POP int attrInst string
D1 Agua Rasa 85896 1
D2 Cangaiba 137442 2
D3 Capão Redondo 240793 3
7
Database Model
Change in Geometry
DistrictsG DistrictsG DistrictsG
geomId int objId string spatialD spatial
1 D1 bbbbbbbbbbbbb
2 D2 bbbbbbbbbbbbb
3 D3 bbbbbbbbbbbbb
4 D1 bbbbbbbb
DistrictsStatus DistrictsStatus DistrictsStatus
attrInst string geomInst string timeI time timeF time
1 1 01/01/2003 31/12/2003
2 2 01/01/2003
3 3 01/01/2003
1 4 31/12/2003
DistrictsA DistrictsA DistrictsA
CODDIS string NOME string POP int attrInst string
D1 Agua Rasa 85896 1
D2 Cangaiba 137442 2
D3 Capão Redondo 240793 3
8
Database Model
Change in Attributes
DistrictsG DistrictsG DistrictsG
geomId int objId string spatialD spatial
1 D1 bbbbbbbbbbbbb
2 D2 bbbbbbbbbbbbb
3 D3 bbbbbbbbbbbbb
4 D1 bbbbbbbb
DistrictsStatus DistrictsStatus DistrictsStatus
attrInst string geomInst string timeI time timeF time
1 1 01/01/2003 31/12/2003
2 2 01/01/2003 01/06/2004
3 3 01/01/2003
1 4 31/12/2003
4 2 01/06/2004
DistrictsA DistrictsA DistrictsA
CODDIS string NOME string POP int attrInst string
D1 Agua Rasa 85896 1
D2 Cangaiba 137442 2
D3 Capão Redondo 240793 3
D2 Cangaiba 150000 4
9
Database Model
Change in Attributes and Geometry
DistrictsG DistrictsG DistrictsG
geomId int objId string spatialD spatial
1 D1 bbbbbbbbbbbbb
2 D2 bbbbbbbbbbbbb
3 D3 bbbbbbbbbbbbb
4 D1 bbbbbbbb
5 D3 bbbb
DistrictsStatus DistrictsStatus DistrictsStatus
attrInst string geomInst string timeI time timeF time
1 1 01/01/2003 31/12/2003
2 2 01/01/2003 01/06/2004
3 3 01/01/2003 21/09/2004
1 4 31/12/2003
4 2 01/06/2004
5 5 21/09/2004
DistrictsA DistrictsA DistrictsA
CODDIS string NOME string POP int attrInst string
D1 Agua Rasa 85896 1
D2 Cangaiba 137442 2
D3 Capão Redondo 240793 3
D2 Cangaiba 150000 4
D3 Capão Redondo 250000 4
10
ST Data - Examples

• Crime events crime occurrences in a city,
  specifying its time and location
• Which crimes happened on Friday in the
  Humaitá district of Porto Alegre city?

11
ST Data - Examples

• Epidemiological data the weekly counting of
  mosquito eggs in a set of traps arbitrarily
  deployed over a city
• http//saudavel.dpi.inpe.br/
• How many eggs were counted by trap in each month?
  

12
ST Data - Examples

• Land parcels
• For each month, which changes occurred in the
  parcels?

13
The Querier Processor Architecture
Application Program Interface
14
Querier Parameters

• Layer the source of the ST-Instances
• Chronon defines how the time extension of the
  layer should be divided into a set of time
  frames
• second, minute, hour, day, month, year, day of
  week, day of month, day of year, month of year,
  week of year, hour of day, minute of hour or
  second of minute

15
Querier Parameters

• Aggregate functions how to group a set of
  ST-Instances of a time frame in a representative
  one
• average, sum, counting, variance maximum or
  minimum,
• Which time frames will be retrieved
• controls if the Querier should returns either
  every time frame existent in the total interval
  of the data or only the time frames where some
  change occurred

16
Querier Parameters

• Temporal predicate defines a relation between
  the data and the time frames (as specified by the
  Chronon)
• temporal interval predicates equals, before,
  after, meets, during, overlaps, ends or starts
  Allen,1983
• Spatial predicate defines a relation between the
  data and a geometry
• disjoint, touches, crosses, within, overlaps,
  contains, intersects, equals, covers and covered
  by Egenhofer and Franzosa, 1991

17
Querier Examples

• Return all crime events, their location and
  properties

CrimeLayer database-gtgetLayer (Crimes)
18
Querier Examples

• Return all crime events, their location and
  properties

CrimeLayer database-gtgetLayer (Crimes)
Querier-gtsetParams(loadGeometries,
loadAllAttributes) Querier-gtsetParams(CrimeLayer)

19
Querier Examples

• Return all crime events, their location and
  properties

CrimeLayer database-gtgetLayer (Crimes)
Querier-gtsetParams(loadGeometries,
loadAllAttributes) Querier-gtsetParams(CrimeLayer)

Querier-gtloadInstances()
20
Querier Examples

• Return all crime events, their location and
  properties

CrimeLayer database-gtgetLayer (Crimes)
Querier-gtsetParams(loadGeometries,
loadAllAttributes) Querier-gtsetParams(CrimeLayer)

Consume the instances
Querier-gtloadInstances()
while (Querier-gtfetchInstance(sti))
Geometry sti.getGeometry()
Properties sti.getProperties()
Time sti.getTime()
21
Querier Examples

• Which crimes happened in 2003 in the district
  Cabanga of Recife city?

DistrictLayer database-gtgetLayer
(Districts) DistrictGeometry
DistrictLayer-gtgetGeometry(Cabanga)
22
Querier Examples

• Which crimes happened in 2003 in the district
  Cabanga of Recife city?

DistrictLayer database-gtgetLayer
(Districts) DistrictGeometry
DistrictLayer-gtgetGeometry(Cabanga)
Querier-gtsetParams(loadGeometries,
loadAllAttributes) Querier-gtsetParams(CrimeLayer,
year, ChangedTimeFrames) Querier-gtsetSpatialRest
riction(DistrictGeometry,within)
23
Querier Examples

• Which crimes happened in 2003 in the district
  Cabanga of Recife city?

DistrictLayer database-gtgetLayer
(Districts) DistrictGeometry
DistrictLayer-gtgetGeometry(Cabanga)
Querier-gtsetParams(loadGeometries,
loadAllAttributes) Querier-gtsetParams(CrimeLayer,
year, ChangedTimeFrames) Querier-gtsetSpatialRest
riction(DistrictGeometry,within)
TimeFrame Querier-gtgetTimeFrame(2003) Querier
-gtloadInstances(TimeFrame) while
(Querier-gtfetchInstance(sti)) ...
24
Querier Examples

• How many eggs were counted in each trap in each
  month?

TrapLayer database-gtgetLayer (Traps)
25
Querier Examples

• How many eggs were counted in each trap in each
  month?

TrapLayer database-gtgetLayer (Traps)
GroupingAttributes-gtinsert(num_eggs,
SUM) Querier-gtsetParams(loadGeometries,
GroupingAttributes) Querier-gtsetParams(TrapLayer,
month, ChangedTimeFrames)
26
Querier Examples

• How many eggs were counted in each trap in each
  month?

TrapLayer database-gtgetLayer (Traps)
GroupingAttributes-gtinsert (num_eggs,
SUM) Querier-gtsetParams(loadGeometries,
GroupingAttributes) Querier-gtsetParams(TrapLayer,
month, ChangedTimeFrames)
numTimeFrames Querier-gtgetNumTimeFrames() for
(frame0 to numTimeFrames) Querier-gtloadInstan
ces(frame) while (Querier-gtfetchInstance(sti))
...
27
Querier Examples

• Which changes occurred in the land parcels in
  each month?

ParcelLayer database-gtgetLayer (Parcels)
28
Querier Examples

• Which changes occurred in the land parcels in
  each month?

ParcelLayer database-gtgetLayer (Parcels)
Querier-gtsetParams(loadGeometries,
loadAllAttributes) Querier-gtsetParams(ParcelLayer
, month,ChangedTimeFrames, Starts Ends)
29
Querier Examples

• Which changes occurred in the land parcels in
  each month?

ParcelLayer database-gtgetLayer (Parcels)
Querier-gtsetParams(loadGeometries,
loadAllAttributes) Querier-gtsetParams(
ParcelLayer, month,ChangedTimeFrames, Starts
Ends)
numTimeFrames Querier-gtgetNumTimeFrames() for
(frame0 to numTimeFrames) Querier-gtloadInstanc
es(frame) while (Querier-gtfetchInstance(sti))
...
30
The Database Change Observer

• The Querier mechanism is being implemented in the
  TerraLib environment
• TerraLib spatial and temporal structures
• TerraLib Generic Database Application Interface
• Support to MySQL, Oracle Spatial, PostGIS,
  PostgreSQL
• www.terralib.org
• The application shows the status of a
  spatio-temporal database

31
ST Database Observer
32
Observing the crime events
?
33
Observing the crime events
34
Observing the egg traps
35
Observing the egg traps
36
Observing the egg traps
37
Observing the egg traps
38
Observing the land parcels
39
Observing the land parcels
40
Observing the land parcels
41
Observing the land parcels
42
Observing the land parcels
43
Final Remarks

• The proposed architecture of a geographical
  database fulfills the demands of our
  spatio-temporal applications
• The spatio-temporal database model is simple and
  can be implemented in different DBMS
• A Querier Mechanism based on the combination of
  spatial and temporal parameters is a flexible
  alternative to deal with the different
  applications

44
Future Improvements

• The Querier mechanism has to deal with two
  layers
• Ex fire spots and deforestation two different
  data set that is highly related in space and in
  time
• Build a catalog of some well-known operations
  such as trajectory using the Querier mechanism
• Study the possibility of using the Querier
  mechanism as a processor for a ST-Language

45
The Architecture of a Flexible Querier for
Spatio-Temporal Databases

• karine, lubia, gribeiro, cartaxo,
  gilberto_at_dpi.inpe.br
• www.dpi.inpe.br