AN INFORMATION SYSTEM FOR THE SHORTEST

ORIGEN-DESTINATION ROUTE IN A TRANSPORTATION

NETWORK

Jos

e Raymundo Marcial Romero, Oscar S

anchez Flores

Facultad de Ingenier

ıa, Universidad Aut

onoma del Estado de M

exico, Toluca, Edo. de M

exico, M

exico

ector A. Montes Venegas, Luis Nu

nez V

azquez, Israel Hern

andez S

anchez

Facultad de Ingenier

ıa, Universidad Aut

onoma del Estado de M

exico, Toluca, Edo. de M

exico, M

exico

Keywords:

Information systems, Transportation systems, Shortest origin-destination algorithms.

Abstract:

There exist several information systems to ﬁnd and display the shortest origin-destination route in a trans-

portation network. Usually these systems are created by organizations purchasing expensive software aiming

to build them easily, quickly and correctly. This goal, however, still remains elusive. In this paper, an in-

formation system that ﬁnds and displays the shortest origin-destination route in a transportation network is

presented. The system is mainly built using free software. In the literature, there were found at least three fast

algorithms to obtain the shortest route in a given network. From these three, one was selected for being more

efﬁcient and less memory consuming according to the experimental analysis carried out. The functionality of

the system is showed using Toluca’s transportation network, one of the largest cities in Mexico.

1 INTRODUCTION

The widespread use of Information and Communica-

tion Technologies has increased the interest in new

developments in computing. One of such devel-

opments are the Geographical Information Systems

(GIS). GIS technology has been extensively used to

deal with issues such as crime analysis (Chainey and

Ratcliffe, 2005), meteorology (Dyras et al., 2005),

transportation (Wu, 2007; Mitra, 2007), urban plan-

ning (Easa and Chan, 2000), among other applica-

tions.

Nowadays, a desirable and often necessary fea-

ture of a GIS is the presentation of geographical in-

formation in real time over the internet. There is

a huge amount of software both commercially and

freely available to design such applications. The wide

variety of applications supported by commercial soft-

ware has been one of the strong advantages over free

software which is often limited to the level of tech-

nical support available and to what the free software

group is interested in. However, commercial soft-

ware for GIS applications has been characterized for

its high licensing costs (Newham and Field, 2001).

A common use of a GIS is the cartographi-

cal presentation of a required place. For example

GoogleMaps (http://maps.google.com) is well known

for presenting the cartography of a vast number of

cities in the world. The design of a GIS for other

applications such as calculating and displaying the

shortest Origin-Destination (O-D) route over a trans-

portation network has not been widely carried out

over the world. One of the limitations to develop

this kind of applications is the necessity of an accu-

rate database with the required information. In differ-

ent continents around the world there are well known

applications. One of such applications is MapQuest

(http://www.mapquest.co.uk) developed in the United

Kingdom. Even though we can search in MapQuest

for maps of almost every country around the world,

the O-D route is limited to European and North Amer-

ican countries. GoogleMaps, Map24, among others

are not the exception.

In this paper, an Information System (IS) is pre-

sented which integrates: Geographical information,

database information and freely available software.

The IS ﬁnds and displays the shortest route between

two different places in a transportation network. One

of the relevant characteristics of our IS is that it can

be used freely in any city or country provided the re-

quired database information is available. Our IS is

tested in the transportation network of Toluca, one of

409

Raymundo Marcial Romero J., Sánchez Flores O., A. Montes Venegas H., Nuñez Vázquez L. and Hernández Sánchez I. (2008).

AN INFORMATION SYSTEM FOR THE SHORTEST ORIGEN-DESTINATION ROUTE IN A TRANSPORTATION NETWORK.

In Proceedings of the Tenth International Conference on Enterprise Information Systems - HCI, pages 409-412

DOI: 10.5220/0001722304090412

 SciTePress

the main cities of Mexico.

The paper is organized as follows. In Section 2,

the algorithm used to implement the shortest O-D

route is described. In Section 3, the components used

to build the GIS are presented. In Section 4 the func-

tionality of the GIS is shown. In Section 5, the inter-

face and the answers given by the GIS are presented.

Finally, in Section 6 conclusions and future perspec-

tives are given.

2 ALGORITHMS FOR THE

SHORTEST ROUTE PROBLEM

The analysis of network and transportation systems

within a GIS has become a common practice in many

applications areas. A key problem in network and

transportation analysis is computing the shortest path

between two different locations, especially when the

number of total locations in a real network is of con-

siderable size. Zhan and Noon (Zhan and Noon,

1998) study most of the algorithms for the shortest

route ﬁnding a set of three algorithms that perform

efﬁciently on real road networks. The algorithms

are: 1) the graph growth algorithm implemented with

two queues (TQQ), 2) the Dijkstra’s algorithm imple-

mented with approximate buckets, and 3) the Dijk-

stra’s algorithm implemented with double buckets.

Later on, Zhan (Zhan, 1999) presented the data struc-

tures and some implementation strategies related to

the algorithms. Pallottino (Pallottino, 1984) showed

that the TQQ algorithm performs better than the other

two, running in O(n

m) time in the worst case. For

this reason, we use the TQQ as part of the IS pre-

sented in this paper. The algorithm used to compute

the shortest O-D route is at the core of our IS in order

to provide proper and efﬁcient responses to user re-

quests. Similarly, a number of other important com-

ponents were used to build the system as an integrated

and independent application. We discuss those in the

next section.

3 COMPONENTS OF THE IS

The great variety of applications to design a GIS leads

to employ a criterion to select those that offer the best

functionality for the system to be built. In this Sec-

tion the major software components used to build the

Information System are described.

Amongst the open source operating systems con-

sidered, the Linux CentOS distribution was cho-

sen. CentOS is a freely available linux distribution

based on the popular Red Hat Enterprise Linux (Jang,

2004). It supports 64 bits processors, is stable, is safe

and it offers sufﬁcient user support.

PostgreSQL (Douglas and Douglas, 2005) is a

well known SQL compliant, open source object-

relational Database Management System. Since the

realease of 7.4.8 version, module PostGIS (Michell,

2005) is included, which gives support for geo-

graphic objects. This new module allows to design

an object-relational database inside PostgreSQL. The

use of this feature as a backend for the GIS, al-

lows the manipulation of spatial data, such as ESRI

SDE (http://www.esri.com) the spatial extension from

Oracle

(Rahayu, 2005).

Tomcat (http://www.apache.org) was used as a

web container coupled with the web server Apache

to support applications using the Java Development

Kit (JDK). Both Tomcat and Apache are conﬁgured to

work in a virtual host architecture in order to receive

the income requests at the port 8080 and only those

requiring the execution of Java Server Pages (JSP)

are sent internally to Tomcat.

MapServer (Kropla, 2005) is an open source

development environment for designing and im-

plementing spatially-enabled internet applications.

MapServer allows to create ”geographic image

maps”, that is, maps that can direct users to content.

MapServer is an interpreter for spatial data. The pow-

erful capabilities and support that MapServer brings,

was the best option for our Information System.

In Addition to the software described above, some

packages were added to improve interaction and func-

tionality for users and developers. Among this soft-

ware MapScript, Proj4, GDAL, QGIS, pgAdmin III

and JDBC were used.

4 THE IS AT WORK

The objective behind our IS is to integrate both a

friendly to use and a friendly to manage system.

This involves enabling diverse hardware an software

components to work together, sharing maps and data

throughout a common communication channel. It is

expected, thus, that having an IS like this available in

real time over the Internet, requires to solve a large

number of technical details. This section provides an

overview of the way the system works both internally

and under the command of the end user.

4.1 The System Internals

The diagram depicted in ﬁgure 1 shows the main com-

ponents of our IS. The Database Management System

ICEIS 2008 - International Conference on Enterprise Information Systems

410

PostgreSQL (9 in ﬁgure 1) heavily interacts with sta-

tistical and cartographical information coming from

different sources. The statistical information is orig-

inated from a number of databases provided by gov-

ernmental organizations and private companies (1 in

ﬁgure 1). Additional information also comes in the

form of simple tabular data (2 in ﬁgure 1) and is pro-

vided by several vendors and also collected by des-

ignated staff. This two pieces of information need to

be validated, integrated and standardized according to

the format of our database design (4 in ﬁgure 1). Car-

tographical information is also originated in formats

similar to those of statistical information (5 & 6 in

ﬁgure 1) and also goes through a validation and stan-

dardization process using QGIS (7 in ﬁgure 1). The

subsequent step is to use PostGIS (8 in ﬁgure 1) to

add the cartographical data to the central database (9

in ﬁgure 1). This is the core of the entire IS.

The remaining components provide the user in-

terface and create a communication link between the

central database and the end user. Throughout any

web browser (14 in ﬁgure 1), users can make a query

to the IS. The response to a certain query might al-

ready be predeﬁned and stored (15 in ﬁgure 1), so

the answer can be given with no delay in the form

of either statistical reports and graphs (16 in ﬁgure 1)

or with cartography and thematic maps (17 in ﬁg-

ure 1). Finally, communications are properly handled

by Apache and Tomcat (13 in ﬁgure 1) to alow the

GIS software MapServer (12 in ﬁgure 1) to gather

data from the central database and present it to the

user in the form of statistical information and maps

(10 &11 in ﬁgure 1).

4.2 The User Interface

The GIS is the central part of the whole Information

System. The sequence of steps taken to give a re-

sponse to any given query are as follows:

1. The user introduces a pair of streets representing

the origin point, i.e., the intersection of the streets

must exists. Similarly, the user introduces a pair

of streets representing the destination point.

2. If the data entered is correct, a search in the data-

base is performed in order to ﬁnd the nodes that

represent the streets given by the user. The re-

sult may be more than one intersection depend-

ing on the number of streets with the same name

found. This is not a database inconsistency. The

existence of duplicate street names often occurs

among different areas of large cities.

3. The algorithm described in Section 2 is executed

in order to get the shortest routes of the given

nodes.

Figure 1: Diagram of the main components of the Informa-

tion System.

4. As a result, for each O-D route found, the se-

quence of nodes, which has to be traversed in or-

der to get the proper direction, is obtained.

5. From the sequence of nodes, the SQL query

is built to obtain the appropriate map from

MapServer.

6. The sequence of nodes is transformed to the cor-

responding sequence of streets names by means

of a query to the database.

7. The set of results is displayed to the user. The user

has then to choose one of them to build the map.

8. Mapserver is initialized and the corresponding

map is drawn with the route calculated.

5 A SAMPLE OF TEST RESULTS

The Information System described in this paper was

tested using the geographical data from the city of

Toluca (www.toluca.gob.mx). Toluca is the state cap-

ital of the State of Mexico in central Mexico. It

is located 63 kilometers from Mexico City and is a

very successful industrial and commercial center. The

municipality of Toluca, which includes several com-

munities, has a geographical extent of 420.14 km

In the 2005 census (INEGI, 2005) 467,713 people

were reported living in the city of Toluca, 747,512

AN INFORMATION SYSTEM FOR THE SHORTEST ORIGEN-DESTINATION ROUTE IN A TRANSPORTATION

NETWORK

411

living in the municipality of Toluca, and 1,610,786

in the twelve municipalities that make up its entire

metropolitan area.

Table 1 shows a small sample of various query

instances and the time taken by the IS to give a re-

sponse. It is worth noting that each instance is evalu-

ated in real time. The tests were carried out in a 64-

bits Server with 2GB in RAM and 1.8 Hz dual core

processor.

Table 1: Time and routes found in several instances.

Instance O-D routes found Time taken

23611.06 m

18769.40 m

17123.91 m

13330.05 m

8675.97 m

13364.39 m

1715.93 m

36.94 s

2 16594.72 10.95 s

3 2715.31 m 13.6 s

2464.52 m

2528.62 m

2450.52 m

8.7 s

6 CONCLUSIONS

In this paper we have described an Information Sys-

tem built using free software to compute and display

the shortest origin-destination route in a transporta-

tion network. GIS technology and Internet commu-

nications are used to manipulate spatial data and to

respond to user requests in real time.

In a large number of instances, the information

delivered provides effective and attractive results, but

they still remain expensive to integrate and to deploy.

In this sense, free software offers a cost-effective al-

ternative to counteract the economic burden of imple-

menting large scale IS.

Nevertheless, implementing GIS technology us-

ing free software should not be taken as a univer-

sally proven proposition. While the economic ben-

eﬁts could be sufﬁcient to opt for a free software en-

semble, the recognized problems associated with non-

commercial software should not be ignored. There-

fore, the potential costs and beneﬁts must be under-

stood in the context of the particular environment in

which the Information System is implemented.

Finally, before deciding which Information Sys-

tem should be used for a particular need, it is essen-

tial to realize and accept the numerous costs associ-

ated with the technology to be implemented. Hard-

ware needs, permanent staff and maintenance costs

must be taken into account. In addition, the often for-

gotten time cost must also be considered, for in many

cases, a couple of years is required to start seeing sig-

niﬁcant and palpable results. Nevertheless, the costs

of implementing GIS technology are lower than ever,

and before looking for expensive solutions is always

advisable to learn from previous experiences.

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