PostTrajectory : Querying and Managing GPS and Trajectories on PostgreSQL/PostGIS KiHyun Yoo E-mail:...
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Transcript of PostTrajectory : Querying and Managing GPS and Trajectories on PostgreSQL/PostGIS KiHyun Yoo E-mail:...
PostTrajectory : Querying and Managing GPS and Trajectories on PostgreSQL/PostGIS
KiHyun Yoo
E-mail: [email protected]
Introduction
In modern cities, many people drive the vehicles that equipped with the GPS devices It is easily being collected and stored the GPS data
Many applications for location-based services(LBS) and moving object have been studied using these GPS data
Moreover, we can use a large-scale GPS data Because it is easily collected from the vehicles Recently it is increasing studies for mining a meaningful and a valuable information
from the large-scale data
Motive
The trajectory is the set of information of the location by the time Unfortunately traditional spatial database systems do not support data types and
functions for trajectory data
PostgreSQL is probably one of the best solutions for trajectory data It is an open-source ORDBMS(Object-Relational Database Management System) Supports objects, classes and inheritance in database schemas and query language
Large-scale trajectory data is useful By analyzing and predicting the trajectory data, it provide a new opportunity to
understand the city dynamics and economic phenomena
Framework
GeoContentsClient(Phone)
PostgreSQL DB
PostGIS
PostTrajectory
GeoContentsClient(Tablet)
GeoContentsClient(Web)
Data Types
Functions
Server
PostTrajectory
Data Types
Function_1
Function_2
Function_3
….
PostTrajectory
Type Functions
Temporal TP_Equals, TP_Before, TP_Meets, TP_Overlaps, TP_During, TP_Intersects, ....
TrajectoryTR_IsEmpty, TR_Append, TR_Update, TR_Delete, TR_AtInstant, TR_Passes, TR_At,
TR_AtPeriods, TR_Inside, TR_Length, TR_Distance, ....
Data Types
INSTANT, PERIOD, MPOINT, MREAL, MBOOL, ....
PostTrajectory (Cont.)
Q1) What is the longest distance that was travelled by a vehicle during the periods?
SELECT Max(TR_Length(TR_AtPeriods (traj.Trip, ‘PERIOD(5005, 5008)’))) AS Dist
FROM Trajectory traj
WHERE TR_Present(traj.Trip, ‘PERIOD(5005, 5008)’);
Q2) Which vehicles travelled within one of the regions from City's Table during the periods?
SELECT c.Region AS Region, traj.car AS car
FROM Trajectory traj, City c
WHERE NOT (TR_IsEmpty(TR_At(TR_AtPeriods(traj.Trip, ‘PERIOD(5005, 5008)’), c.Region)));
PostTrajectory (Cont.)
Applications