Geographic Information on Computer Maps and LBS--论文代写范文精选

可以从两种不同的方法，通用的服务,在用户明确表示他或她的位置和定位服务,位置的自动获得以透明的方式给用户,而不是使用设备。同时,LBS系统可以划分他们，根据活动的用途。下面的essay代写范文进行详述。

LBS (Location Based Services) are services that based on user’s geographic location, can provide relevant information to his or her geographic position. The main purposes that a LBS system includes are the identification, search and verification of services that are nearly to a user’s position, fulfilling tasks as identifying a user’s location, locate other persons, objects or places, and provide guidance, information or help to find a particular place [11]. The main characteristic from LBS services is that they provide just in time information to the users, considering that the information presented must be from a particular domain of interest to the user and that this information be useful and can be used in the geographic area the user is at. Steiniger [12] presents LBS systems as an infrastructure composed by: users, a communication network, a positioning component (such as a GPS), LBS service provider and data and content providers.

The content provider turns to the service provider in order to obtain the geographic data and information needed to answer the user’s query. LBS design can be considered from two different approaches: generic services, in which a user explicitly denotes his or her location (i.e. giving street names or zip code) and locatable services, in which the location is automatically obtained in a transparent way to the user, using devices instead, as a GPS. Also, LBS systems can be classified under different focuses, according to the activities they are going to be used for. For example, they are classified considering if they are going to be used for gaming, getting information or paying bills [13], meanwhile in [14] they are classified according the consumers.

There have been developed different formats in order to facilitate the managing of POIs information and users visited geo-routes between computer devices. These formats can be used for the representation of geographic location on Web maps, for example: LOC, GPX and KML, which are based on XML. The earlier map applications on mobile devices worked the same visualization that the one used on desktops and on Internet; this presented some troubles due to the different situations that the mobile environment required, because mobile applications have had smaller screen displays in comparison to common desktop applications; also, mobile applications are commonly used on open spaces, making its users’ needs different.

These caused that the first difficulties that the LBS systems confronted, fallen on the type of interaction presented between the user and his or her mobile device, the device itself presented limitations caused by its portability; also on the limited visual representation of the earlier mobile devices, due by the low screen resolution, a limited bandwidth (situation which step by step has been counteracted with mobile technology advances such as the 3G network), and also due to the huge diversity of mobile devices, each one showing different functionalities, causing that it was necessary to develop particular device’s applications.

Actually, the diversity of installed platforms on mobile devices has started to unify, thanks to the apparition of more opened systems, such as Android. Today, the market of locating services is a commercial sector at growth, supported by big companies, such as Nokia (with its Nokia Maps and other services), Google (with services as Googke SMS and Google Maps for Mobile), AOL (with MapQuest) or Ask (with Ask Mobile GPS), among many others. At the same time, on the Web can be found an immense variety of applications focused on services geo-locating and routes guidance, for example GPS navigation services (e.g. amAzeGPS). Research work includes those that combine distinct technologies in order to give a mayor variety of creative applications, for example GiMoDig [15], pedestrian navigational guides [16] and such ones that combine augmented reality techniques with contents from Wikipedia [17], or those that applies these technologies for gaming, as in TikGames site or in [13]. This relevance on these types of applications has motivated the apparition of contests that motive the development of new and creative uses that take advantage of these technologies.

Mashups
Actually, the use of Web maps that combine information from different sources and gives a more complete user’s experience has become common: the so called map mashup. The mashups are a genre of interactive Web applications that enable to retrieve content from external sources and create new services; they are a stamp of the Web 2.0. Mashups are mainly composed of an API / content provider (i.e. Google Maps, MapQuest, among a variety of Web map providers), the Web site in which the mashup is presented and by the client’s Web browser; they involve a diverse set of interrelated technologies, they usually use AJAX and Web protocols as SOAP y REST; some other are also related with the use of semantic Web, ontologíes and the integration of RSS and ATOM feeds [18]. There are different types of mashups, from videos and photos mashups, until those about sales, searches and news.

The case of the digital maps is that they have become a multi purpose centralized tool, used for local business, traffic reports, online dating, among other uses that are related to a specified time and place. The collaborative participation plays an important role in the use of map mashups, as it has been shown in projects such as Wikimapia (www.wikimapia.org) for the collaborative description of world POIs; other case is Tagzania (www.tagzania.com), which is based on the social tagging of places. Considering the previous examples, the map mashups can be used in social searching of places and geo-locatable services in Web maps.

This has encouraged the apparition of APIs that facilitate the creation of mashups, such as the ones developed by Google or Yahoo’s FireEagle API, which can be used for searching of commercial places, such as restaurants or stores (e.g. Yelp.com site); and there is also the inclusion of geolocation components natively inside Web browsers based on W3C Geolocation Specification [19], which can be used to exploit more similar applications and newer ones.

The activity of the users has become an important part in the operation of the mashups; users can participate actively being volunteers that tag their favorite places or by being consumers of these map mashups geo-location services. However, the social collaboration in relation with the geo-locatable information has a bigger transcendence; this has been indicated in the collaborative geographic information systems.

Collaborative GIS
The development of GIS dates back to 60’s, with the apparition of GIS as computational tools for capturing, managing and transforming data of spatial references to be used in planning and decision-taking processes. Other work that followed after these, was trying to provide a support for the integration between groups of people and for the decision-taking based on geo-referential data, studying also the impact of them on its users. The development of these systems continued and took advantages of the Internet era, in which the Web maps has a fundamental situation, as is mentioned in [20]; this evolution has been passed to technological issues and the adoption of open standards and the collaborative use inside the social networks [21]. The use of GIS has shown to impulse the capacity of community groups to recognize their necessities, priorities and knowledge.

It is in this way that the collaborative GIS appeared. Collaborative GIS are an integration of theories, tools and technologies focused on structuring the human participation on group processes of geospatial-decision. Their objective is to use the argumentation, deliberation, the clear structure of maps and the reconciliation between different groups with representative interests [20]. Meanwhile the Web distribution allows freeing of the spatial barriers in the use of GIS, the use of mobile devices helps in the task of recollecting local data. This integration has helped towards a mobility that allows reaching people and places which under other circumstances could not be considered nor contributed to the spatial information of a GIS. The use of GIS interfaces in the form of thin clients over the Internet has made possible to create maps and the download of spatial information without the need of having to install a complete GIS application. This has changed and made easier the way in which the users access and participate in collaborative planning forums; thanks to this, the users of collaborative maps not only receive geographic information, but also let them actively contribute in the process, generating a cycle of mutual feedback between the users and the map service.

Contextual Information
A context-aware system is a system that considers the context in which is immersed, in order to provide relevant information and services to a user, in which the relevance is defined according the user’s task and according to his or her spatial and temporal situation. There are different senses to define what the context is. For example, on one hand, the context is considered to be all the things that allow to determine a possible set of responses, or on the other hand, context is all the things that are necessary to understand a query; some dictionaries define it as a physical or situational environment, should be political, historical, cultural or from other nature, in which a fact is considered. Nivala [22] considers that context is any information that can be used to characterize the situation o fan entity (person, place or object).

In his way, Sun [23] indicates that the context includes from external aspects from the environment of a person (i.e. geographic physical features, cultural events) to interior aspects (personal fitness and healthy). In this way, the context can be considered as a pervasive element, which has been researched under different focuses of use, e.g. the context modeling for geographical applications [24], for intelligent personalized touristic guides [23] and also for places querying and searching, taking advantage on the use of ontologies [25], [26], [27]. In an application, the context-awareness can be active (this is when the application can be adapted automatically to the context in which it is in, this information can be received actively when the user introduces it directly to the application) and can be passive (when the application automatically detects the context, giving to the user the decision of accepting or rejecting the options showed by the application). The same information can be accessed by the users for different purposes and under different contexts; depending on the user, it will be the context of the application. It is for this that ways of identifying different contexts of use for the same information has been searched.（essay代写)

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