An example of a tourist location based service lbs with open source software
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Geospatial World Forum Hyderabad 21/01/11. An Example Of A Tourist Location Based Service (Lbs) With Open Source Software. M. Deidda, A. Pala, G. Vacca University of Cagliari, ITALY DISIG Department of Structural Engineering, Infrastructural and Geomatic [email protected]

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An Example Of A Tourist Location Based Service (Lbs) With Open Source Software

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An example of a tourist location based service lbs with open source software

  • Geospatial World Forum Hyderabad 21/01/11

An Example Of A Tourist Location Based Service (Lbs) With Open Source Software

M. Deidda, A. Pala, G. Vacca

University of Cagliari, ITALY

DISIG Department of Structural Engineering, Infrastructural and Geomatic

[email protected]


Contents

Geospatial World Forum Hyderabad 21/01/11

Contents

  • Introduction

  • Definition of Location Based Service (LBS)

  • LBS Standards

  • Experimentation

  • Conclusions


Introduction

Geospatial World Forum Hyderabad 21/01/11

Introduction

  • Tourism is an economic sector in constant expansion, also due to technologies and services allowing tourists to request specific information in real time, through the Internet, everywhere in the world. Among these services there are Location Based Service (LBS), which are based on the current geographic location of the user.


What is an lbs service

Geospatial World Forum Hyderabad 21/01/11

What is an LBS Service?

  • Some tourists want to go to a restaurant, so they can to search it on the Internet. A better and faster way to locate it is to add further research criteria. A good choice is to add the area where the users are (position), the time when they want to eat (morning or evening) and the specific kind of restaurant they are looking for (e.g. Indian or Italian). This search can be done by using a Location Based Service .

“Great Wall” Chinese Restaurant

Silk Road, 45

Open Fri-Wed

Dinner only

Where?

When?

What?

Position

Information


What is a lbs

Geospatial World Forum Hyderabad 21/01/11

What is a LBS

  • The LBS is composed of 4 components.


Mobile device

Geospatial World Forum Hyderabad 21/01/11

Mobile device

  • A tool for the user to request the needed information to service provider. The results can be given by speeches, pictures, texts and so on.

  • Possible devices can be PDA, Mobile Phones, Laptops......

  • But also car navigation units or tool boxes for road pricing in a lorry.

PDA

Navigator

Mobile Phone

Smartphone

Laptop PC


Communication network

Network technology

Average range

Data Rate(Mbps)

Frequency domain

WWAN

GSM (G2)

Base station distance 100m – 35 Km

0.009 - 0.014

~900 MHz, licensed Spectrum

GPRS

0.160

UMTS (G3)

2.0

WLAN

Ultra Wideband

10 m

100

~2.4 & 5 GHz, not licensed Spectrum

IEEE 802.11a

50 m

54

IEEE 802.11b

100 m

11

~2.4 GHz, not licensed Spectrum

Bluetooth

10 m

1

WPAN

HomeRF

50 m

10

IrDA (Infrared)

1-1.5 m needs line of sight

1 - 16

not licensed Spectrum

Geospatial World Forum Hyderabad 21/01/11

Communication Network

  • The second component is the communication network, which transfers the data from the mobile device to the service provider and vice versa. This can be a Wireless Wide Area Network (WWAN) - GSM or UMTS, a Wireless Local Area Network (WLAN) - IEEE 802.11 or a Wireless Personal Area Network (WPAN) - Bluetooth.


Positioning component

Geospatial World Forum Hyderabad 21/01/11

PositioningComponent

  • The positioning component is used to locate the mobile device. Several positioning techniques are used in LBS; these differ from each other in positioning accuracy, Time To First Fix (TTFF), service coverage, or costs and they are classified as follows:

  • Hybrid

Terminal-based

positioning

Network-based

positioning


Service provider

Geospatial World Forum Hyderabad 21/01/11

Service Provider

  • The service provider offers a number of different services to the user and it is responsible for the service request processing. Thanks to such services it is possible:

  • to calculate the positioning,

  • to find a route,

  • to search in Yellow Pages,

  • to search specific information on objects of user interest


Data provider

Geospatial World Forum Hyderabad 21/01/11

Data Provider

  • Service providers will not usually store and keep all the information requested by users. Therefore, geographical database and location information data will be usually requested by authorities like mapping agencies or business partners like the Yellow Pages or traffic companies.


The lbs standards

Geospatial World Forum Hyderabad 21/01/11

The LBS Standards

  • To perform a Location Based Service a number of different elements, from technology to data providers, have to be included. To ensure that all the different technologies and devices work together, common standards for interfaces and descriptions have to be defined.

  • - The ISO/TC 211 : 19132 (Location based services possible standard), 19133 (Location based services tracking and navigation) and 19134 (Multimodal location based services for routing and navigation).

  • - The Open Geospatial Consortium (OGC): OpenLS .


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

The OpenLS Standard


The experimentation

Geospatial World Forum Hyderabad 21/01/11

The experimentation

  • The experimentation is aimed at:

  • studying the accuracy of the positioning component, in particular in the GPS receivers for LBS applications

  • - performing an Info-tourist LBS application complying with the OpenLS standard and developed with Free and/or Open Source software


Positioning component1

Geospatial World Forum Hyderabad 21/01/11

PositioningComponent

  • The choice of a LBS positioning component depends essentially on two factors:

  • 1.required accuracy of the LBS kind

  • 2.operating conditions, such as outdoor or indoor


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

The receivers used in the test are the following:

• HP iPAQ hw6915: HSGPS, 12 channels.

• GeoXT, Trimble L1, 12 channels

• Juno, Trimble L1, 12 channels


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

  • The tests have been performed in critical conditions by recreating the operating conditions of LBS terminals, such as cities (urban canyons), shopping centers (indoors), under trees, etc.

  • These conditions cause an absence or a degradation of the GPS signals, which affect the position calculation as follows:

  • • The receiver cannot fix the position;

  • • The positioning accuracy is not appropriate for the specific application;

  • • The waiting time to calculate the position is too long.


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

  • In particular, the following parameters have been studied:

  • • Accuracy is the degree of closeness of measurements of a quantity to its actual (true) value. 

  • • Sensitivityintended as a measure of the receiver ability to track the satellites in conditions where the signal is heavily degraded (the ability to perform the pseudo-range measurement)

  • • Consistencyintended as the chipset ability to obtain a consistent positioning in every condition.


The test

Geospatial World Forum Hyderabad 21/01/11

THE TEST

  • To study the parameters a path was surveyed. The path was represented by some parts where the GPS signal was in part attenuated and other where the GPS had full visibility.

  • The path was surveyed with a sampling rate of 1 Hz.


Accuracy

Geospatial World Forum Hyderabad 21/01/11

Accuracy

  • In order to assess the accuracy the path surveyed is compared with the same path surveyed with greater accuracy.

Juno survey

Ipaq survey


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

The charts show the frequency histograms, where the ordinates correspond to the percentage of acquired GPS position within the following accuracy ranges:

  • Under 1 m

  • Between 1 and 2 m

  • Between 2 and 5 m

  • Between 5 and 10 m

  • Over 10 m (and up to a maximum of 100 m)


Sensitivity

Geospatial World Forum Hyderabad 21/01/11

Sensitivity

  • To verify the receiver sensitivity we considered the number of receiver epochs recorded (one per second), also if in some epochs no position was available and these were compared with the acquired positions (independent of error )


Consistency

Geospatial World Forum Hyderabad 21/01/11

Consistency

  • It is the chipset ability to obtain a consistent positioning in every condition for further usages.

  • In order to study this aspect we analyzed the percentages of positions acquired with an accuracy better than 10m (maximum allowable error for stand-alone positioning in these conditions)


The info tourist lbs application

Geospatial World Forum Hyderabad 21/01/11

The Info – Tourist LBS Application

  • The LBS implemented by the Geomatics team of the University of Cagliari simulates an info-tourist service in Cagliari town centre.

  • Infrastructure and application consist of:

  • 1. mobile device with GPS receiver and Internet network access. We used the S8000 Jet smartphone Samsung

  • 2. Client software for the mobile device

  • 3. LBS server

  • 4. WMS (Web Map Service) and WFS (Web Feature Service) server - Geoserver

  • 5. Database of the tourist interest point.

  • The application was developed with Free and/or Open Source software and complies with the OpenLS standard for LBS services.


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

In the Info-tourist LBS developed, the client sends its position and asks to the LBS server the information on the closest tourist point. In OpenLS terms this means to make a ReverseGeocode operation.

The answer is displayed on the mobile device together with a map coming from the WMS and WFS Services


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

THE LBS SERVER

  • xls.py: contains the classes for interpreting the request messages and building the response messages in XLS, the XML format used in OpenLS for client-server communications

  • location_utility.py: implements the Location Utility Service, for the part concerning the Reverse Geocoding operation

  • rgc_xls.py (“Reverse GeoCode”) is a Web Application following the WSGI (Web Server Gateway Interface) standard


The lbs server sequence of operations

Geospatial World Forum Hyderabad 21/01/11

The LBS server: Sequence of Operations

  • The program starts by loading into memory the points of interest as a Feature Collection, and constructing a Locator object (defined in simplefeatures.py) associated to them.

  • Then it passes control to the WSGI server, which waits for requests.

  • When a ReverseGeocodeRequest is received, it is interpreted for extracting the GPS position.

  • The Locator object selects from the Feature Collection the points of interest which are nearer than a predefined search radius to the given position.

  • For each point of interest, a FreeFormAddressobject is constructed and initialized with its attributes.

  • Then the address objects are encapsulated in the ReverseGeocodeResponse which is sent to the client.


The lbs client

Geospatial World Forum Hyderabad 21/01/11

The LBS Client

Based on gvSIG Mini by Prodevelop (http://www.prodevelop.es/)

  • Based on gvSIG (Open Source GIS by the Generalitat Valenciana)

  • Written in Java ME (Mobile Edition)

  • Running on CLDC (Connected Limited Device Configuration) devices


The map

The map used in the Web Map Service is the 1:1000 scale map of the city of Cagliari in Shapefile format.

Originally in the Roma40 national reference system, it was converted to geographic coordinates in the ETRF89 reference system.

Geospatial World Forum Hyderabad 21/01/11

The Map


The database

The associated database contains all the information useful for an info-tourist LBS. In particular, the sites of historical-cultural-architectural importance have been selected, and for each of them the following data were collected:

Name

Short description

URL of a picture

URL of a Website

Address

Visiting hours

Ticket price

Geospatial World Forum Hyderabad 21/01/11

The Database


Conclusions

The LBS service developed by the research group of the University of Cagliari is currently available only to obtain information for sites of tourist interest

The research group is now implementing new functions; in particular, we are now studying the Route Service in order to calculate the route from the user’s current location to a requested point of interest.

The next step will be to develop a client also for Apple devices like IPhone and Ipad.

Geospatial World Forum Hyderabad 21/01/11

Conclusions


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

  • THANK YOU FOR ATTENTION


An example of a tourist location based service lbs with open source software

Geospatial World Forum Hyderabad 21/01/11

Positioning Accuracy

Low cost GPS

(DGPS or stand-alone mode)

Geodetic GPS

(RTK mode)

HSGPS

A-GPS


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