1. Presentazione corso di Fotogrammetria 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 vaccag@unica.it Geospatial World Forum Hyderabad 21/01/11

2. Presentazione corso di Fotogrammetria Contents Introduction Definition of Location Based Service (LBS) LBS Standards Experimentation Conclusions Geospatial World Forum Hyderabad 21/01/11

3. Presentazione corso di Fotogrammetria 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. Geospatial World Forum Hyderabad 21/01/11

4. Presentazione corso di Fotogrammetria 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. Where?When?What?Position “Great Wall” Chinese Restaurant Silk Road, 45 Open Fri-Wed Dinner only Information Geospatial World Forum Hyderabad 21/01/11

5. Presentazione corso di Fotogrammetria What is a LBS The LBS is composed of 4 components. Geospatial World Forum Hyderabad 21/01/11

6. Presentazione corso di Fotogrammetria 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. Laptop PC Navigator Mobile Phone Smartphone PDA Geospatial World Forum Hyderabad 21/01/11

7. Presentazione corso di Fotogrammetria 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. Geospatial World Forum Hyderabad 21/01/11

8. Presentazione corso di Fotogrammetria Positioning Component 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 Network-based positioning Terminal-based positioning Geospatial World Forum Hyderabad 21/01/11

9. Presentazione corso di Fotogrammetria 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 Geospatial World Forum Hyderabad 21/01/11

10. Presentazione corso di Fotogrammetria 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. Geospatial World Forum Hyderabad 21/01/11

11. Presentazione corso di Fotogrammetria 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. Geospatial World Forum Hyderabad 21/01/11

12. Presentazione corso di Fotogrammetria The OpenLS Standard Geospatial World Forum Hyderabad 21/01/11

13. Presentazione corso di Fotogrammetria 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 Geospatial World Forum Hyderabad 21/01/11

14. Presentazione corso di Fotogrammetria Positioning Component 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 Geospatial World Forum Hyderabad 21/01/11

15. Presentazione corso di Fotogrammetria Geospatial World Forum Hyderabad 21/01/11

16. Presentazione corso di Fotogrammetria 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 Geospatial World Forum Hyderabad 21/01/11

17. Presentazione corso di Fotogrammetria 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. Geospatial World Forum Hyderabad 21/01/11

18. Presentazione corso di Fotogrammetria In particular, the following parameters have been studied: Accuracy is the degree of closeness of measurements of a quantity to its actual (true) value. Sensitivity intended 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) Consistency intended as the chipset ability to obtain a consistent positioning in every condition. Geospatial World Forum Hyderabad 21/01/11

19. Presentazione corso di Fotogrammetria 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. Geospatial World Forum Hyderabad 21/01/11

20. Presentazione corso di Fotogrammetria Accuracy In order to assess the accuracy the path surveyed is compared with the same path surveyed with greater accuracy. Ipaq survey Juno survey Geospatial World Forum Hyderabad 21/01/11

21. Presentazione corso di Fotogrammetria 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) Geospatial World Forum Hyderabad 21/01/11

22. Presentazione corso di Fotogrammetria 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 ) Receiverexpected positions acquired positions % JUNO183109265 GeoXT10303316030.7 iPAQ hw6915207141252660.5 Geospatial World Forum Hyderabad 21/01/11

23. Presentazione corso di Fotogrammetria 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) Receiver% of accuracy < 10m JUNO90 GeoXT96.4 iPAQ hw691574.5 Geospatial World Forum Hyderabad 21/01/11

24. Presentazione corso di Fotogrammetria 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. Geospatial World Forum Hyderabad 21/01/11

25. Presentazione corso di Fotogrammetria 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 Geospatial World Forum Hyderabad 21/01/11

26. Presentazione corso di Fotogrammetria 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 Geospatial World Forum Hyderabad 21/01/11

27. Presentazione corso di Fotogrammetria The LBS server: Sequence of Operations 1. 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. 2. Then it passes control to the WSGI server, which waits for requests. 3. When a ReverseGeocodeRequest is received, it is interpreted for extracting the GPS position. 4. The Locator object selects from the Feature Collection the points of interest which are nearer than a predefined search radius to the given position. 5. For each point of interest, a FreeFormAddress object is constructed and initialized with its attributes. 6. Then the address objects are encapsulated in the ReverseGeocodeResponse which is sent to the client. Geospatial World Forum Hyderabad 21/01/11

28. Presentazione corso di Fotogrammetria The LBS Client Based on gvSIG Mini by Prodevelop (http://www.prodevelop.es/)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 Geospatial World Forum Hyderabad 21/01/11

29. Presentazione corso di Fotogrammetria 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

30. Presentazione corso di Fotogrammetria 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

31. Presentazione corso di Fotogrammetria 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

32. Presentazione corso di Fotogrammetria THANK YOU FOR ATTENTION Geospatial World Forum Hyderabad 21/01/11

33. Presentazione corso di Fotogrammetria Positioning Accuracy Geodetic GPS (RTK mode) Low cost GPS (DGPS or stand-alone mode) HSGPS A-GPS Geospatial World Forum Hyderabad 21/01/11