providing methods for the capture and analysis of dynamic phenomena through a postgresql extension
DESCRIPTION
52°North Innovation Prize for Geoinformatics 2013 winner Peter Broßeit presents his concept and prototype of a PostgreSQL extension for time.TRANSCRIPT
Providing methods for the capture and analysis ofdynamic phenomena through a PostgreSQL extension
Peter Broßeit
2
Is the time still an issue in geoinformatics?
3
Capabilities for spatio-temporal analyses in today‘s GIS are at best vestigialData storage through existing data types –> No unified modelling in the time dimension
Where and when did the most tornados happen during the
last 10 years in Europe?
Which land use features are the predecessors of a particular nature reserve?
Are there temporal overlappings between
various data sets or features?
Is the time still an issue in geoinformatics?
4
Concept
• Modelling the valid time dimension withone user defined data type
• Instants, periods of time and temporal complexes• Based on ISO19108
Actual Purpose:
Unified modelling -> homogeneous queriesExplicit modelling of periods of time and temporal complexes
5
Temporal Schema - ISO19108
Schema to describe the temporal characteristics of geographic information
Feature attributes, feature operations & feature associations
• Temporal objects• Various reference systems• Combination with features
6
The Temporal Objects
TM_Primitive
ISO19108
7
The Temporal Objects
MultiPrimitive
TM_Primitive
ISO19108
8
The Temporal Objects
TemporalPositionISO19108
9
The Temporal Objects
TemporalPositionISO19108
10
The Temporal Objects
Only one internal system
TemporalPositionISO19108
11
Textual Representation
• Necessary for the information exchange-> The user’s view on the database level
• Some terms are set by the Temporal Schema (ISO19108)
The concerning standardisation does not go far enough-> Requires arbitrary specifications-> Only restrictedly suitable for a general information exchange
Actually needed: WKT for time
?
12
Operations
Basic functionsOperating only in the time dimensione.g. Simple queries, Boolean operations, ISO19108-Functions
Spatio-temporal analysisIntegrated processing in the spatial and temporal dimensione.g. ISO19108-Feature Successions
13
Relative Position
14
ISO19108 – Feature Successions
Feature SubstitutionFeature DivisionFeature Fusion
May be derived trough a combined use of temporal and spatial operations
15
Why PostgreSQL?
Standard compliance and far-reaching possibilities in configurationSpatial functionality provided by PostGIS -> OGC compliant
Implementation with PostgreSQL
User defined base type in PostgreSQL
Current capabilities:The six object typesExemplary the three types of reference frameVarious basic functionsExamples for spatio-temporal analysis
16
What are the predecessor and successor associations between several countries?
Shapefile: WEIDEMANN, N. B.; DOREEN, K.; GLEDITSCH, K. S. (2010): The Geography of the International System: The CShapes Dataset, http://nils.weidmann.ws/projects/cshapes/shapefile (2013-03-07).
17
For each time step: In which state did the most tornados take place?
Shapefile: NATIONALATLAS.GOV (2011): nationalatlas.gov – Map Layers, http://nationalatlas.gov/maplayers.html (2013-03-07).
18
Perspective
Purpose: From the proof-of-concept to the first release
• Extend the range of functions• Decent documentation• Extensive testing• Validation of the concept
Particular:
Managing the various reference framesSyntax for the information exchangeUser defined reference frames
Documentation with Doxygen
