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STANDALONE FRAMEWORK FOR MOBILE GIS Mohamed Eleiche∗, Béla Márkus∗ A mobil GIS önálló környezete – A mobil eszközök egyre gyorsabban terjednek, a felhasználóik száma exponenciálisan növekszik. Az eszközbe építetett digitális kamera mellett, a GPS vevő és a drót-nélküli kommunikáció jelentik a fő komponenseket. A mobil felhasználói tábor igényli a GIS szolgáltatásokat. A tanulmány elemzi a kliens/szerver környezetre alapuló mobil GIS jellemzőit, és fogalmi szintű javaslatot tesz egy új önállóan is működő mobil GIS szolgáltatásainak kialakítására. Kulcsszavak: mobil GIS, helyfüggő szolgáltatások The mobile devices are expanding, and their user base is increasing exponentially. The GPS receiver and wireless communications in addition to hardware architecture and digital camera are the main components of mobile devices. The GIS functionalities are required to mobile users for many purposes. This paper analyzes the current framework of mobile GIS based on client/server architecture and proposes a new conceptual framework for the implementation of GIS functionalities on mobile devices. Keywords: mobile GIS, location-based services 1 Introduction In 1980, when IBM established the first Personal Computer (PC) from different hardware components, a new page in the history of human innovation started, and triggered a new technological revolution by creating the machine that according to Thomas Freidman made the world flat. Little bit earlier, the first trial for commercial cellular network started in Chicago (Wikipedia) and even earlier in 1971, Ray Tomlinson sent the first email. These actions triggered the information and communication technology (ICT) revolution and shaped our present and will shape our future. Many experts agree that the exponential evolution of mobile devices and mobile networks (up to 4th Generation in 2008) will trigger a similar revolution to PC impact in the early eighties (BernersLee 2007). The traditional PC is vanishing, notebooks and laptops are replacing traditional PCs, as published by MAIT (Manufacturers Association for Information Technology) in 2007, 114% growth in the sales of laptops compared to 1% growth in the sales of desktops. Notebooks have smaller shapes, powerful capabilities, and most notably cheaper price. The expectation is that the mobile device and the notebook will converge to a degree creating a new machine in the size of mobile device and with notebook capabilities or closer. Maps and geospatial date are essential information for everyone, and GIS provides the required technology for enabling them digitally. GIS invaded also the mobile market, and the mobile GIS is known as the GIS technology used for displaying and manipulating geospatial data on mobile devices. The purpose of this paper is to present and analyze the current framework of mobile GIS technology, and how it works. Also, the paper proposes a new framework for mobile GIS where the user can use GIS functionalities offline when the internet connection is lost or while working outside coverage area. A definition for mobile GIS is proposed, and the mobile device is introduced. 2 Definition of mobile GIS The mobile GIS does not have a concrete definition, the same thing happened to GIS many years ago. There are many disciplines and technologies that can be related to mobile GIS, such as LBS (Location Based Services), and telegeoinformatics (Li et al. 2002, Karimi and Hammad 2004, *
University of West Hungary, Faculty of Geoinformatics Nyugat-Magyarországi Egyetem, Geoinformatikai Kar 8000 Székesfehérvár, Pirosalma u. 1-3. E-mail:
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Fangxiong and Zhiyong 2004). The same issue is similar to mobile device, which has many characteristics that differ from one device to another. Assuming that a mobile device is a portable device with mobile communication capabilities, processor, RAM, and local storage hard disk, can surf the internet and be connected to GPS device. Smartphone, PDA (Personal Data Assistant) and Pocket PC are samples of mobile devices. Mobile GIS will be defined as the ability of mobile device to display geospatial data, and receive, process, and retrieve the GIS requests of mobile user. The most common framework for mobile GIS is to be considered as an extension to Web-GIS, where the GIS requests of the mobile user are processed via internet web browser. This framework was extended and tailored to display geospatial data and perform GIS operations on mobile device. The comparison between laptop and mobile devices are given in Table 1. 2.1 Characteristics of mobile device The mobile device is similar to small notebook, as some experts like to call it mini-laptop. This new device is a mix between mobile phone device, which is used for GSM communication, and in the same time it has its own processor, RAM and hard disk which are the main components of the PC. Usually, the mobile device has a GPS-receiver attached to it, which provides its positional awareness and a digital camera. In the past, the mobile device was used as mobile phone and as advanced organizer, and with advancement in technology development, it became an important device that links to databases, perform transaction operations, browse the internet, and display geospatial data. The mobile device is similar to small notebook, as some experts like to call it mini-laptop. This new device is a mix between mobile phone device, which is used for GSM communication, and in the same time it has its own processor, RAM and hard disk which are the main components of the PC. Usually, the mobile device has a GPS-receiver attached to it, which provides its positional awareness and a digital camera. In the past, the mobile device was used as mobile phone and as advanced organizer, and with advancement in technology development, it became an important device that links to databases, perform transaction operations, browse the internet, and display geospatial data. Table 1. Comparison between laptop and mobile device
Item RAM Hard Disk Processor Screen Size Screen Resolution User Interface
Laptop 2 – 4 GB 100 – 700 GB 2000 – 2700 MHz 10" – 17"
Mobile Device 16 – 384 MB 0.5 – 16 GB 400 – 800 MHz 2" – 5"
600 x 800 – 1920 x 1200 Mouse – standard keyboard – camera – voice – remote control
240 x 320 – 352 x 800 Small size keyboard – pen stylus – voice – camera High competing market, changing dynamically main OS: Symbian OS, Windows mobile, RIM Blackberry, iPhone, Linux, and many others Wireless only Battery only 120 millions unit (Information Week) (increase 60% than 2006) Available via Web-GIS and limited number of GIS softwares with limited capabilities
Operating System
Matured established OS: Microsoft, Apple, Linux
Communication Power Market Sales (2007)
Wire, wireless Electricity/Battery
GIS Functionalities
18 millions unit (PC magazine) Many free and commercial GIS software and tools
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The main characteristics of GIS mobile device are wireless communication to the internet, GPS equipments, and its hardware. The GIS mobile device has to connect to GIS server where the geodatabase that interests the user resides. 3. Current mobile GIS framework The mobile GIS is used for many purposes. Two major purposes can be identified as geospatial data entry and GIS operations. The data entry use of mobile GIS allows the GIS user/operator to collect geospatial data and store it on the mobile device, to be edited/retrieved/analyzed later on the mobile device or stored on GIS server. The second major use is the GIS operations, where the GIS user displays the geospatial data on his mobile device then selects a GIS operation to be performed on a set of geospatial data. The current mobile GIS is practically an enhanced version of Web-GIS, where the GIS users can explore and process GIS operations through an internet browser or via a special tailored application such as the famous Google Earth. As shown in Fig. 1. the current mobile GIS framework is a client/server architecture based on wireless communication between the mobile device and GIS server where the geospatial database is resident. In this framework, the GIS user displays the geospatial data, commonly in georeferenced raster format with low resolution to be suitable to the limited hardware capabilities of mobile device. The GIS user initiates a GIS operation using the GUI (Graphical User Interface) on the mobile device and the displayed data. The request is sent to the GIS server via wireless communication, and then the GIS server provides the required geospatial data and processing power for the request. After the request is processed, the results are sent to the mobile device for display. 3.1 Analysis of current framework The current framework is characterized by: – The framework is defined as Client/Server architecture. – The full dependence on the wireless communications, once disconnected the mobile GIS user cannot perform GIS analysis. – The wireless communication of the mobile device consumes the battery power and reduces its working time.
Fig. 1. Current Framework for Mobile GIS
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– – – – – –
The communication server is exhausted by dedicating the required bandwidth to transmit the mobile GIS requests in both directions. All the client requests and server replies can be monitored. The GIS server should supply the required processing power for each GIS request. The GIS functionalities available for the user are limited and controlled by the server side. The cartographic output is out of control the user of mobile GIS. The performance of this framework is slow, and depending on many elements and parties such as mobile device itself, wireless communication, working environment, and GIS server.
4 Proposed conceptual framework for standalone mobile GIS The proposed mobile GIS framework is designed to overcome the limitations of the current framework, and extend the functionalities of GIS to mobile users even in offline mode when the mobile user is outside the coverage area or when the GIS server is down. The proposed framework is based on sending the part of interest from the geodatabase to the mobile device where it will be stored, and then the second thing is to build GIS applications for mobile device to access the local stored partial geodatabase in the hard disk of mobile device. As shown in Fig. 2., the proposed mobile GIS framework is designed to extract the part of interest from the geodatabase and send it to the mobile device to be stored on its local hard disk, the part is extracted from geodatabase (1), then sent to internet server (2), then moved to communication server (3), then finally stored on the hard disk of mobile device (4). The mobile device will have mobile GIS application to perform GIS operations on the part of geodatabase resident on mobile device. 4.1 Advantages of proposed mobile GIS framework The proposed conceptual framework for mobile GIS has several advantages, first it allows the Mobile GIS user to work in offline mode, which impacts on reducing the bandwidth load on the com-
Fig. 2. Proposed Framework for Standalone Mobile GIS Geomatikai Közlemények XII., 2009
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munication network and decreases the operation cost. Secondly, the performance of the GIS operation will increase, due to its dependence on RAM-Processor-Hard Disk only rather than depending on the performance of both the communication and GIS servers in the current framework. Thirdly, the GIS user can perform the required analysis, edit the geospatial data, and runs the required tailored GIS applications according to his needs more precisely than the limited GIS functionalities enabled from GIS server to the mobile client. The security of the mobile GIS user is achieved in the proposed framework, since only the transmission of data from server to client can be monitored not the requests nor the results of mobile GIS operations. It is evident that the proposed framework will provide for mobile GIS users in case of emergency and loss of wireless communications with servers a valuable tool for navigation and decision support, especially if it is equipped with GPS receiver. 4.2 Requirements for Proposed Framework –
Re-engineer GIS applications to accommodate the limited hardware capabilities of mobile device such as limited RAM, small processor and limited hard disk space. Mobile GIS applications should perform the same functionalities of traditional GIS applications but based on the limited hardware resources of the mobile device. – Implement mobile cartographic methodology to display geospatial data on the small size screen of mobile device with its limited resolution. – Dense and compact geospatial data models to reduce its storage size on the mobile device and increase processing performance. – Interoperability for geospatial data between GIS server and mobile device. – Sophisticated update techniques and versioning capabilities for main geodatabase on GIS server due to receiving several versions of the same data from several mobile GIS users. – Standards to enable the re-use of data and applications for the immense and heterogeneous base of mobile device users. The possible GIS functionalities for mobile device are summarized in table 2. Table 2. Possible GIS functionalities for mobile device
GIS Functions Geospatial data collection Indoor navigation Pedestrian navigation Bicycle navigation Mobile tracking Car navigation Emergency Trip planning
Description Bottom-up geospatial data collection including multimedia and position can be performed using mobile devices with GIS functionalities for geospatial data editing and update Navigation in large buildings such as universities campus, malls, airports, railway stations is a challenge, where spatio-temporal actions are critical, and GNSS signals are not available Pedestrian navigation is different than vehicle navigation, and it has its own characteristics and algorithms Bicycle navigation is different than vehicle navigation, and it has its own criteria and routes Tracking people is important in mobile and real time operation, for example children in a trip or tourists in foreign place Car navigation is related to online traffic data, which changes the chosen route and requires online update for the new path Emergency cases where servers are not available and fast decisions based on spatial data are necessary Planning of trips or change of plans is a decision based on geospatial data and needs special GIS functionalities
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5 Conclusion The proposed conceptual framework for standalone mobile GIS is conforming to the future vision of the convergence between mobile devices and notebooks, and establishes a basis for the future implementation of GIS with a wide range of users equipped with mobile device enhanced with a GPS-receiver. The GIS applications based on immense amount of hardware resources is not applicable to the proposed framework. A new design of GIS applications for mobile devices is required to perform selected GIS functionalities using limited hardware resources and reduce size of geodatabase. Also, the mobile geospatial data model needs to be compacted for reducing the required bandwidth while data transmission and to accommodate the limited hard disk space on the mobile device. References Li L, Li C, Lin Z (2002): Investigation on the Concept Model of Mobile GIS. Symposium on Geospatial Theory, Processing and Applications, Ottawa. Karimi H A, Hammad A (2004): Telegeoinformatics: Location-Based Computing and Services, Chapter 10, Taylor & Francis CRC Press, Florida, USA. Fangxiong W, Zhiyong J (2004): Research on a Distributed Architecture of Mobile GIS based on WAP, XXth ISPRS Congress, Istanbul, Turkey Berners-Lee T (2007): The Mobile Web, Mobile Internet World conference, Boston.
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