PostTrajectory : Querying and Managing GPS and Trajectories on PostgreSQL/PostGIS

KiHyun Yoo

E-mail: khyoo1221@gmail.com

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

Thank you

Any Questions?

khyoo1221@gmail.com