B. Murgante et al. (Eds.): ICCSA 2014, Part II, LNCS 8580, pp. 532–546, 2014. © Springer International Publishing Switzerland 2014

ClickOnMap: A Framework to Develop Volunteered Geographic Information Systems with Dynamic

Metadata

Wagner Dias de Souza, Jugurta Lisboa-Filho, Jean Henrique de Sousa Câmara, Jarbas Nunes Vidal Filho, and Alcione de Paiva Oliveira

Departamento de Informática, Universidade Federal de Viçosa (UFV) Viçosa, MG, Brasil

wagnerdiasdesouza@gmail.com, jugurta@ufv.br, jean.camara@ufv.br, jarbasfito@hotmail.com, alcione@dpi.ufv.br

Abstract. Volunteered Geographic Information (VGI) features a specific type of “user-generated content" that involves spatial data. Geobrowsers are envi-ronments that present spatial data dynamically and can be accessed through a compatible browser. A Geobrowser can own a collaborative Web system to col-lect VGI. This paper presents the ClickOnMap, a framework to develop colla-borative environments in Geobrowsers in a quick and standardized way. The framework has an architecture to document VGI and supports the generation of metadata following the rules of a dynamic metadata template for VGI called DM4VGI. Thus, the data can be interoperable with other systems that do not use ClickOnMap. CidadãoViçosaMG is a system to collect VGI about Viçosa city that was developed from ClickOnMap. The VGI collected in this system was documented using the DM4VGI template. The paper presents a quantitative analysis of VGI collected and of dynamic metadata generated to assess the usa-bility of ClickOnMap along with DM4VGI.

Keywords: VGI, Geobrowser, framework, dynamic metadata.

1 Introduction

Topographic mapping reached its peak as a government-sponsored activity in the 1950s and 1960s, but has been declining over the years because it is a costly and time consuming activity [7]. Governments have been gradually reducing use and invest-ment in mapping to reduce costs. Researchers and government agencies from many countries seek alternatives to reduce costs and increase production of spatial data [2], [4].

The evolution of Web 1.0 to Web 2.0 allowed the development of Web Collabora-tive Systems, including systems that use spatial data. A Web phenomenon known as user-generated content [9] is increasing and diversifying the creation of data provided

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via collaborative environments [13], [19]. The free encyclopedia Wikipedia1, the global volunteer mapping OpenStreetMap2, Wikimapia3 and even customer reviews about the quality of a product (e.g. Ebay4) are examples of this phenomenon.

Collaboration involving geographic data, so-called Volunteered Geographic Infor-mation (VGI) [7], characterizes a specific type of user-generated content. VGI com-bines three key elements, the Web 2.0 [11], the concept of Collective Intelligence [10] and what has been defined as Neogeography [16].

Geobrowser is a system that allows the user to access, in a simple and intuitive way, a data set and dynamic geospatial information [12]. It also can provide a colla-borative module that allows search, access, visualization and integration of geospatial data interactively. However, the lack of standards for collecting and documenting VGI has been a huge barrier to recovery and interoperability of volunteers’ data be-tween different Geobrowsers.

By using volunteers interoperable data is possible, for example, to cross data from a system that collects information about infrastructure problems of a city with a sys-tem that maps diseases in that city. Based on VGI, the public authority can act using information provided by the population or the population may carry out actions inde-pendent of the government. Souza et al. [14] proposed the DM4VGI template for documenting VGI via dynamic metadata, i.e., metadata automatically captured during a voluntary contribution.

This paper presents the ClickOnMap framework designed to enable the rapid de-velopment of VGI collection systems, with support for documentation of dynamic metadata using the template DM4VGI. It also presents quantitative analyses of a set of VGI collected in the collaborative Web system CidadãoViçosaMG5 that was im-plemented from the ClickOnMap framework.

The rest of the paper is structured as follows: Section 2 lists the top Web map ser-vices that currently exist, a review on VGI and discusses some related works; Section 3 introduces the framework ClickOnMap, its functionalities and structure; Section 4 describes a case study developed from ClickOnMap; Section 5 presents the conclu-sions of the study and proposes future research.

2 Volunteered Geographic Information

VGI, according to Elwood et al. [4], represents a dramatic shift in content, feature and mode of creation of geographic information, as well as sharing, dissemination and use of these data. In a VGI environment, the user can constantly collaborate to increase the database, and help in the collection, validation and analysis of data quality, reduc-ing costs of production and data management.

1 https://pt.wikipedia.org/ 2 http://www.openstreetmap.org/ 3 http://wikimapia.org/ 4 http://www.ebay.com/ 5 http://www.ide.ufv.br/cidadaovicosa

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Citizen participation as a ‘human sensor’ to collect, edit and update data in a Geo-browser has been discussed and analyzed in the scientific community [1], [7]. These users are also seen as ‘helpers for validation of information’, as they may provide ratings or reviews of the collaborations, besides describing the experience of VGI post-use [6].

VGI can be used to approximate citizens to political and administrative sectors, for instance, helping to map infrastructure problems or crime occurrences in a city, which is called e-Government [5].

2.1 Web Map Services

There are a number of web map services; Table 1 lists some of them. Google Maps API was chosen as the basis of the framework of this work because of the following factors: (1) greater compatibility with most browsers6, thus covering a larger number of users; (2) Street View assists in identifying sites at the moment you collaborate; (3) access speed as fast or faster than competitors. Nevertheless, several other Web Map Services on Table 1 can be used in the replication of this work without impairing the results.

2.2 Related Works

Davis Junior et al. [3] proposed a framework for developing collaborative environ-ments to collect and make VGI available in the Web and mobile device applications. The structure includes all components required to implement various VGI applica-tions. The objective of this framework is to reduce the effort of developing and pub-lishing new VGI topics. Therefore, it is possible the creation and the quick customiza-tion of VGI environments to collect data from current events.

Another environment available is the Ushahidi Platform [17]. It originated from the site Ushahidi that means ‘testimony’ in Swahili (official language of Kenya, Tanzania and Uganda). This site used VGI to map, expose and process information of crime, violence and peace efforts during the post-election period in the early 2008 in Kenya, based on reports submitted via the Internet and mobile phones. Later, the site turned into the computing platform Ushahidi Platform that can be used by people worldwide for collection of information, visualization and interactive mapping. It is based on dynamic maps that receive voluntary cooperation through markers associated with information balloons, where the user can click a point on the map and make a contri-bution, characterizing, in this way, a framework for developing collaborative systems.

These two systems do not provide functions for documentation (metadata) and va-lidation of VGI quality. There are no tools with extra functionality for analyzing vo-lunteer data. They do not provide methods to improve VGI quality and do not allow Wiki revisions on collaborations such as is proposed by this work.

6 http://en.wikipedia.org/wiki/Comparison_of_web_map_services

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Table 1. Web Map Services and their APIs

Service Name Official Website API and Libraries

Apple Maps http://www.apple.com/br/ios/maps/ https://developer.apple.com/library/ios/

documentation/userexperience/conceptual/ LocationAwarenessPG/MapKit/MapKit.html

Bing Maps http://br.bing.com/maps/ http://www.microsoft.com/maps/ choose-your-bing-maps-API.aspx

CloudMade http://maps.cloudmade.com/ http://blog.cloudmade.com/category/api/

Géoportail http://www.geoportail.gouv.fr/ http://www.programmableweb.com/api/

geoportail Google Maps https://maps.google.com.br/ https://developers.google.com/maps/

Map.Geo.Admin.ch http://map.geo.admin.ch/ http://api.geo.admin.ch/main/wsgi/doc/build/ Mappy http://en.mappy.com/ http://www.programmableweb.com/api/mappy

MapQuest http://www.mapquest.com/ http://developer.mapquest.com/ Nokia Here http://here.com/ http://developer.here.com/

OpenLayers http://openlayers.org/ http://dev.openlayers.org/apidocs/files/

OpenLayers-js.html OpenStreetMap http://www.openstreetmap.org/ http://wiki.openstreetmap.org/wiki/Develop

Yahoo! Maps http://maps.yahoo.com/ http://developer.yahoo.com/maps/

3 The ClickOnMap Framework

The ClickOnMap framework was designed to develop collaborative modules in Geo-browsers based on the Google Maps API. This API provides functions, methods, maps and satellite imagery to assist in the development of a Geobrowser. It has sup-port to the capture of user actions, e.g., to capture latitudes and longitudes in geo-graphic coordinates of points selected by mouse clicks. It has classes of markers, info windows and geometry of point, line and polygon. Thus, it enables the development of the collaborative module.

The ClickOnMap environment is customizable according to the categories and types of data one wants to collect, for example, data on urban issues such as infra-structure, security and entertainment, or environmental issues such as natural disasters, forest fires and floods. The system can accept anonymous or identified col-laboration depending on the system policy. For instance, in an environment about crime and anonymous crime tips, the user may want not to be identified, but in an environment that collects data on the positive quality of shops the users can even benefit from their collaboration. Figure 1 shows the structure of the ClickOnMap database.

All VGI captured via ClickOnMap is dynamically documented by the DM4VGI template [15]. Thus, the data collected can be interoperable among different Geo-browsers. For example, every spatial collaboration has its limits documented by a bounding box element present in the DM4VGI. Then, it is possible to perform fast searches based on spatial comparisons. It is also possible to perform temporal or the-matic data searches from the DM4VGI elements that allow it, e.g., date and time of the collaboration (or instance) to carry out a temporal comparison over time, and cat-egory and type of collaboration to perform a thematic comparison. In addition, from VGI metadata collected by systems that use DM4VGI one can achieve interoperabili-ty of VGI.

536 W.D. de Souza et al.

Fig. 1. Structure of the ClickOnMap database

The framework has full support for the automatic capture of all elements of the DM4VGI template. The template values are built from: data present in VGI, e.g., title, date of collaboration, category and type; data provided by Geobrowser functions, e.g., zoom level, user’s IP, name of the collected site; data generated from the interaction between the user and the Geobrowser functions, e.g., the level of user ranking at the time the collaboration is performed and the final score of the collaboration.

The main features of the ClickOnMap system are described below.

3.1 User Types

ClickOnMap allows four distinct types of users. Each type of user has a set of privi-leges and acts differently on the system.

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• Unidentified user - a user who does not perform any type of identification and cannot work or evaluate data in the system; user can only view and download the volunteer data.

• Anonymous user - when a user wants to collaborate without directly being identi-fied. The system automatically creates a record of anonymous user with generic name and login: ‘anonymousX’, where ‘X’ is an incremental integer (e.g. ‘ano-nymous 77’). Each time a user requests this type of login another record of ano-nymous user is created. After a logout, an anonymous user (e.g. ‘anonymous 77’) cannot be reused by another user. For security and political issues, the system cap-tures the Internet Protocol (IP) and time of the user’s collaboration, because if the user breaks the law using the system he can be identified by the authorities.

• Registered User – the user who has registered on the website or used a Facebook account or Google to identify her/himself. Only registered users can be notified about the evolution and acceptance of their collaboration.

• Administrator - user responsible for managing the system and collaborations.

ClickOnMap has a ‘User Ranking’ mechanism in which the more points they have the higher their level will be. Every user has a score and is linked to a reliability class. These classes can provide special privileges to users. Table 2 illustrates an example of how users can earn points. This scoring can be configured in each system.

Anonymous users only accumulate points during the current login session. If a user logged in as anonymous logs out, there will be no point accumulation for him because each time a user makes a login as anonymous, a new anonymous user will be created with an initial default score. Therefore, for a user to level up in the hierarchy she/he must have a registration. Users at different hierarchical levels help other users identify the degree of collaborative reliability because the DM4VGI template has elements that store the reliability class and points of users who created and updated the VGI.

Table 2. Users’ points system

User’s Action PointsRegistered for the website +5Collaboration performed +10

Comment performed +5Evaluated collaboration +1

Extra files sent +2 per filePerformed a Wiki review in a VGI +1

Had a collaboration evaluated + (Average or weighted average via user ranking of scores 0-5 of all their collaborations) * (number of

reviews)

Made a false collaboration -15Made a malicious collaboration -50Made a criminal collaboration Baned

3.2 Wiki Review Functions, Queries and Statistical Analyses

The system allows the collaborations are reviewed and edited by any user who has logged in. This type of review can be called WikiVGI. This method may be one way

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to improve VGI quality. All changes made in VGI are stored and displayed in a his-torical format. Thus, if necessary, you can return the collaboration to a previous state. This security procedure is also used on Wikipedia.

When an anonymous user provides a VGI, before this collaboration is made avail-able to the general public, the data are moderated by word filter algorithms and also by administrator users, which becomes a type of control to prevent criminal or mali-cious collaborations from being disclosed. Registered users do not have their collabo-rations moderated, i.e., their collaborations are available to the public immediately.

The system has several tools to assist in data analysis and decision making, includ-ing spatial data analysis, such as kernel map and visualization with marker clustering, both to identify what are the geographical areas that receive the most specific type of collaboration. There is a function that allows historical data search and also follow the Wiki evolution of a VGI. The environment provides pie charts with data on the per-centage of the amount of each type and category of contribution in a particular region of the map, thus enabling to identify the incidence of 'what' is occurring in a region of the map . For example, using this method it is possible to identify the main problems of a neighborhood or a street. There is a visualization based on filters of categories and types, so it is possible to view on the map only contributions from one or more types or categories. The system also features a search on metadata, which may run text, temporal, spatial and thematic searches. Metadata can be downloaded in XML format as shown in Figure 2.

Fig. 2. Example of metadata downloaded

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3.3 Validation of VGI Quality

ClickOnMap validates the VGI quality using four methods: (1) VGI scores; (2) users’ scores; (3) moderators; and (4) administrators.

Each user can give a score from 0 to 5 for each collaboration, aiming to evaluate the quality or reliability of VGI. The final score of the collaboration is calculated by the weighted average on the users ranking. Thus, each user also has a score.

The more points a user has, the higher her/his hierarchical level in the ClickOnMap users ranking. Users at higher levels in the ranking have greater weight in the final collaboration score than users at lower levels. A user who sends quality collaborations may have them rated with higher grades. Thus, this user earns more points than a user who performs many collaborations rated with low grades.

3.4 Administrative Module

ClickOnMap has an administrative module enabling users who have administrative permissions to configure a new collaborative system, as well as to manage collabora-tions and dynamically customize the application. Using this module the user can quickly define a new application based on ClickOnMap. It is necessary to define a set of configurations and establish usage policies for each new system. Table 3 shows the elements that need to be configured.

Table 3. Elements of initial application configuration

Information Item Element

Site

1.1 Name

1.2 Email Login

Password 1.3 Link to homepage

Map

1.4 Latitude 1.5 Longitude 1.6 Zoom level 1.7 Type of map

Login 1.8 Facebook 1.9 Google+

1.10 Anonymous

Item 1.1 in Table 3 registers the name of the system that appears as a title on every

page of the system. Item 1.2 registers the contact email of the application. This email can be used to notify collaborators about changes in the validation status of their col-laborations. Item 1.3 registers the link of the system home page; this link is used to configure the website navigation. Items 1.4 and 1.5 must be filled according to the location where the application is set up, as the map starts with the center at this point. Item 1.6 registers information on the level of the initial map zoom. Item 1.7 registers the type of map, for example, a street map, a satellite image or hybrid. Items 1.8 to 1.10 register the types of optional login the system will have: Facebook, Google or Anonymous. The login from a diary kept in the system will always be available.

540 W.D. de Souza et al.

When developing a new application, it is also possible to establish the categories and types of collaborations, which are the classes of users and their range of points, and what will be the score policy of the application, i.e., according to each user’s action on the system, what will be the amount of points that the user will earn or lose.

The administrative module provides tools to create new users with special permis-sions and a complete environment for managing collaborations, categories and types. One can also change some rule of the system, for example, modify the range of points in user classes or change the score of each user’s action on the system.

The collaboration management enables the validation of a collaboration and write a justification linked to the collaboration that is made persistent in the database. After the positive or negative validation one can send a message to the user who created the collaboration. Figure 3 shows a visualization interface of collaboration to be eva-luated and validated by the administrator. Any collaboration can be deleted by an administrator user.

Fig. 3. Assessment and validation environment of collaboration

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4 The Collaborative Web System CidadãoViçosaMG

The ClickOnMap framework has been used to develop three VGI applications. The system VGI-Pantanal [15] is an environment to gather information related to the envi-ronmental issues of the Pantanal floodplain, located in central-western Brazil. The second system that used ClickOnMap was the system MossoróCrimes [18], aiming to collect voluntary information in the area of public safety of the municipality of Natal, Rio Grande do Norte. The third system, described in detail in this section, was Ci-dadãoViçosaMG, aiming to collect more comprehensive voluntary information on various topics related to Viçosa city, state of Minas Gerais.

Data are collected and stored in a database hosted on its own server, that is, volun-teers data are not sent to Google. Figure 4 shows the home page of CidadãoViço-saMG. Figure 5 shows the collaboration page.

The system offers three login options to ClickOnMap: login from the registration made in the system itself; login from Google and Facebook accounts; and login as anonymous user. Despite in this last option the user does not identify herself or him-self, her/his Internet Protocol (IP) is captured automatically for safety, but only the system administrators will have access to this information.

Fig. 4. Homepage of CidadãoViçosaMG

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Fig. 5. Collaboration page

When performing a login, the user is allowed to enter a new contribution or edit, review, update and evaluate any collaboration in the system. Each collaboration has a forum. So users can comment and discuss about the veracity or quality of a VGI. All contributions can also be Wiki revised.

The system has filters for categories and types to better visualize the information of interest on the map. The user also has access to a news system to see the most viewed, recent, revised or evaluated collaborations.

Some examples of classes defined in the collaborative environment CidadãoViço-saMG are: Entertainment, Infrastructure, Environment, Health, Safety, Service or Product. Each category can be sorted by a set of more specific types. For example, the category Infrastructure has the types garbage collection, water distribution, crosswalk, street lighting, traffic lights, vacant lots. The category Security has the types burglary, anonymous crime tip, theft, policing, location of drug activity, illegal trafficking, domestic violence, others.

CidadãoViçosaMG provides tools for the user to analyze VGI, for example, it has charts with the percentage of each category and type of collaboration . These graphs can also be generated for a specific area on the map, i.e., one can easily see which categories or types of collaborations that occur in a more specific neighborhood.

In the context of validating VGI quality, the system keeps a ranking of users, VGI evaluation through rating scores provided by users and approval via administrators. Administrators analyze the amount of ratings assigned to the collaboration and its final rating. Then, the collaboration can be validated positively or negatively. To do this, the administrators change the status of the collaboration from ‘in review’ to ‘ap-proved’ or ‘disapproved’.

Some users at higher hierarchical levels have permissions to approve or disapprove a collaboration. CidadãoViçosaMG has six reliability classes that can provide special permissions to users. Table 4 shows the reliability classes of this system. The scores can be changed according to the evolution of the system and collaborations.

All VGIs are automatically documented by the VGI documentation module based on the template DM4VGI. Therefore, metadata are dynamic, i.e., as VGI is collected or changed, the corresponding metadata are created or updated.

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Table 4. Reliability classes of CidadãoViçosaMG

Name of the reliability class Scores required to belong to the class

Special Collaborator Over 800Experienced Collaborator Between 500 e 799

Master Collaborator Between 250 e 499Legal Collaborator Between 100 e 249Basic Collaborator Between 0 e 99

Malicious Collaborator Less than 0

4.1 Quantitative Analysis of VGI Collected in the System CidadãoViçosaMG

To analyze quantitatively the collaborations to the system CidadãoViçosaMG, a pe-riod of three months (from 01/08/2013 to 31/10/2013 ) was established. A simple disclosure was made through Facebook and in a list of students of the Federal Univer-sity of Viçosa (UFV). The data for this period are presented next.

According to Google Analytics, 809 visits were performed by 405 different users, i.e., with different IP. The system had 45 collaborations and 100 registered users, with 68 registrations created by ‘login as anonymous user’ and the remaining 32 users are registered in the system or identified by Facebook and Google accounts. The in-creased number of ‘login as anonymous user’ occurred because: (1) users are afraid of being identified, even the system making it clear that the author of the VGI will not be identified by other users; (2) users do not want to waste time performing registration; and (3) users do not want to log in using their Facebook or Google accounts, even the system making it clear that they will not be identified by other users.

The low number of collaborations in relation to the number of accesses may be due to a number of factors: (1) the users do not know exactly with ‘what’ to collaborate to the system; (2) users had difficulty locating a region of interest; (3) people are afraid of being identified, even the website stating that is anonymous collaboration; (4) users may have the feeling that their collaboration will not be judged and analyzed by au-thorities, hence the problems will not be resolved from a VGI system; and (5) the user has no time to perform a collaboration.

The Wiki-VGI system was also little used, having only 6 collaborations of the Wi-ki type in just 3 different collaborations, i.e., 6.7% of contributions had Wiki revision. The reasons may be due to the following factors: (1) the collaborations may be correct in the view of users, hence no need for revision; (2) users did not realize that they could review the collaboration; (3) users identified errors but did not want to inform or did not know how to correct; and (4) users had to provide more information about collaborations but they would not cooperate.

All 45 VGIs were viewed by other users. The total number of VGI visualizations was 1998, that is, on average each of the 45 collaborations were visualized approx-imately 44 times. Thus, it is possible to verify that users are seeking collaborations more than collaborating.

Regarding the amount of metadata collected by this system, all required elements were captured automatically. All optional elements that are generated from the Geo-browser were captured automatically. All optional elements that have been provided

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by users were captured automatically. Thus, provided that the information exists in the datum or in the Geobrowser, it is captured automatically. For example, the date of the collaboration occurrence can only be captured if the user has provided this infor-mation in the voluntary datum, or, the final VGI score can only be captured if any user has provided the score and if the Geobrowser has a module of assessment to calculate this final score. Therefore, the documentation was carried out from the VGI documentation module and succeeded in all collaborations.

4.2 Visualization and Statistics of VGI

Figure 6 shows three types of maps provided by ClickOnMap. The first presents VGI clusters; the second displays all VGI markers; and the third shows the Kernel Map (radius value = 20 of Google Maps API) collaborations. The highest number of colla-borations was performed in the city center. Only 3 collaborations were performed over the campus area of the Federal University of Viçosa. Collaboration only oc-curred in the urban area of the municipality of Viçosa.

Fig. 6. VGI visualization

Table 5 presents a quantitative summary of collaborations according to the catego-ries with the highest number of collaboration. It shows the total amount of collabora-tions each category received and the percentage of collaboration of each category relative to the total collaborations. Most collaborations are related to the categories infrastructure and security.

Table 5. Quantitative analysis of data in relation to categories

Category Amount of collaboration % in relation to total collaboration Missing 0 0

Entertainment 4 8.89Infrastructure 19 42.22Environment 1 2.22

Health 3 6.67Security 7 15.56

Service or Product 8 17.78Other Categories 3 6.67

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5 Conclusions

This paper presents the ClickOnMap framework designed to enable quick and easy development of applications in VGI Geobrowsers. ClickOnMap allows quick custo-mization of a collaborative environment defining a region of interest, user roles, col-laboration permissions and the categories and types the system will offer. The system is useful, for example, to create a VGI application for supporting disaster manage-ment or to make a survey of geographical information on an environmental event which has to be fast responded (e.g., are there or were there fires this week in the region X ?).

The framework has full support to automatic capture of elements of the dynamic metadata template DM4VGI. All data collected by systems using this framework will be interoperable data.

The use of ClickOnMap with DM4VGI in the project CidadãoViçosaMG showed that it is really possible to collect metadata dynamically in collaborative Geobrowsers. All collaborations were properly documented. The VGIs are interoperable because the metadata have a standardized XML structure, which make data both human and ma-chine-readable.

One realizes how difficult it is to obtain a high number of collaborations if the sys-tem is not properly disclosed. If the collaborative Web system has an interface with the possibility of several login options, one can increase the number of collaborations. Tools for both data analysis and user feedback help attract more collaborative users.

The participation of public sectors in managing the Geobrowser is a theme to be explored in future research. For example, collaborations regarding problems or lack of infrastructure or complaints regarding public safety need response from these agents, which could be one more attraction for more users to collaborate positively in the system.

Acknowledgements. Project partially funded by FAPEMIG, CNPq and CAPES and the companies Sydle and Gapso.

References

1. Cooper, A.K., Coetzee, S., Kourie, D.: Perceptions of virtual globes, volunteered geo-graphical information and spatial data infrastructures. Geomatica 64(1), 73–88 (2010)

2. Cooper, A.K., et al.: Challenges for quality in volunteered geographical information. In: Proceedings of Africa GEO 2011, Cape Town, South Africa (2011)

3. Davis Junior, C.A., Vellozo, H.S., Pinheiro, M.B.: A Framework for Web and Mobile Volunteered Geographic Information Applications. In: Brazilian Symposium on Geoin-formatics. Campos do Jordão (SP). Proceedings, vol. 14. Instituto Nacional de Pesquisas Espaciais (INPE), São José dos Campos, SP (2013)

4. Elwood, S., Goodchild, M.F., Sui, D.Z.: Researching Volunteered Geographic Informa-tion: Spatial Data, Geographic Research, and New Social Practice. Annals of the Associa-tion of American Geographers 102(3), 571–590 (2012)

546 W.D. de Souza et al.

5. Furtado, V., et al.: Collective intelligence in law enforcement–The WikiCrimes sys-tem. Information Sciences 180(1), 4–17 (2010)

6. Georgiadou, Y., Bana, B., Becht, R., Hoppe, R., Ikingura, J., Kraak, M.J., Lance, K., Lemmens, R., Lungo, J., Mccall, M., Miscione, G., Verplanke, J.: Sensors, empower-ment, and accountability: a Digital Earth view from East Africa. International Journal of Digital Earth 4(4), 285–304 (2011)

7. Goodchild, M.F.: Citizens as Voluntary Sensors: Spatial Data Infrastructure in the World of Web 2.0. International Journal of Spatial Data Infrastructures Research 2, 24–32 (2007)

8. Goodchild, M., Linna, F.: Assuring the quality of volunteered geographic information. Spatial Statistics 1, 110–120 (2012)

9. Hollenstein, L., Purves, R.: Exploring place through user-generated content: Using Flickr tags to describe city cores. Journal of Spatial Information Science (1), 21–48 (2013)

10. Lévy, P., Bonomo, R.: Collective intelligence: Mankind’s emerging world in cyberspace. Perseus Publishing (1999)

11. O’Reilly, T.: What is Web 2.0: Design Patterns and Business Models for the Next Genera-tion of Software, Disponível (2005), http://www.oreillynet.com/pub/a/oreilly/tim/news/2005/ 09/30/what-is-web-20.html

12. Schrader-Patton, C., Ager, A., Bunzel, K.: GeoBrowser deployment in the USDA forest service: a case study. In: International Conference and Exhibition on Computing for Geo-Spatial Research & Application, Washington, Anais, vol. 1, ACM Digital Library, New York (2010)

13. Shriver, S.K., Nair, H.S., Hofstetter, R.: Social ties and user-generated content: Evidence from an online social network. Management Science 59(6), 1425–1443 (2013)

14. Souza, W.D., Vidal Filho, J.N., Ribeiro, C.A.A.S., Lisboa Filho, J., Oliveira, D.F.: Infor-mação Geográfica Voluntária no Pantanal: um sistema Web colaborativo utilizando a API Google Maps. In: Simpósio de Geotecnologias no Pantanal, Bonito, MS. Proceedings of Simpósio de Geotecnologias no Pantanal (GeoPantanal), vol. 4, pp. 763–772 (2012)

15. Souza, W.D., LisboaFilho, J., Vidal Filho, J.N., Câmara, J.H.S.: DM4VGI: A template with dynamic metadata for documenting and validating the quality of Volunteered Geo-graphic Information. In: Simpósio Brasileiro de Geoinformática (GEOINFO). Campos do Jordão-SP. Proceedingsof São José dos Campos, vol. 14, pp. 1–12. MCT/INPE (2013)

16. Turner, A.: Introduction to Neogeography. O’Reilly Media, Inc. (2006) 17. Ushahidi: Open source software for information collection, visualization and interactive

mapping, http://ushahidi.com/ 18. Vidal-Filho, J.N., Lisboa-Filho, J., de Souza, W.D., dos Santos, G.R.: Qualitative Analysis

of Volunteered Geographic Information in a Spatially Enabled Society Project. In: Mur-gante, B., Misra, S., Carlini, M., Torre, C.M., Nguyen, H.-Q., Taniar, D., Apduhan, B.O., Gervasi, O. (eds.) ICCSA 2013, Part III. LNCS, vol. 7973, pp. 378–393. Springer, Heidelberg (2013)

19. Yildirim, T.P., Gal-Or, E., Geylani, T.: User-Generated Content in News Media. Manage-ment Science (2013)