Multiple Representations in Geographic Information Systems

Geographic information systems (GIS) deal with data which can potentially be useful for a wide range of applications. However, the information needs of each application usually vary, specially in resolution, detail level, and representation style. This thesis presents a set of primitives that allow the specification of operational processes, such as transformations between representations, through the use of a dynamic schema.Sociedad Argentina de Informática e Investigación Operativ

Aplicação de redes neurais artificiais na classificação de áreas cafeeiras em Machado - MG

The coffee is extremely important activity in southern of Minas Gerais and techniques for estimating acreage, seeking reliable crop forecasts are being intensely investigated. It is presented in this study, an application of Artificial Neural Networks (ANN) for the automatic classification of remote sensing data in order to identify areas of the coffee region Machado, Minas Gerais. The methodology for developing the application of RNA was divided intothree stages: pre-processing of data, training and use of RNA, and analysis of results. The first step was performed dividing the study area into two parts (one embossed busiest and least busy one with relief), because this region has a strong emphasis smooth wavy, causing a greater difficulty of automatic mapping of use earth from satelliteimages. Masks were also created in the drainage network and the urban area. In the second step, various RNA’s were trained from several samples representative of the classes of images of interest and was made to classify the rest ofthe image obtained using the best RNA. The third step consisted in analyzing and validating the results, performing across between the classified map and the map visually classified by neural network chosen. We used the Kappa index to evaluate the performance of the RNA, since the use of this coefficient is satisfactory to assess the accuracy of a thematic classification. The result was higher than the results reported in the literature, with a Kappa index of 0.558 to 0.602 relief busiest and least busy for relief.A cafeicultura é atividade de fundamental importância na região sul de Minas Gerais e técnicas de estimativa da área plantada, visando previsões de safra confiáveis, estão sendo intensamente pesquisadas. Apresenta-se,no presente estudo, uma aplicação de Redes Neurais Artificiais (RNA) para a classificação automática de dados de sensoriamento remoto, objetivando identificar áreas cafeeiras da região de Machado, MG. A metodologia para desenvolvimento da aplicação da RNA foi dividida em três etapas: pré-processamento dos dados; treinamento e uso da RNA; e análise dos resultados. Na primeira etapa foi realizada a divisão da área em estudo em duas partes (uma com relevo mais movimentado e outra com relevo menos movimentado), isso porque a região apresenta relevo suave ondulado a forte ondulado, o que acarreta maior dificuldade do mapeamento automático do uso da terra a partir de imagens de satélite. Foram também criadas máscaras na rede de drenagem e área urbana. Na segunda etapa, diversas RNAs foram treinadas a partir de várias amostras de imagens representativas das classes de interesse e foi feita a classificação do restante da imagem utilizando a melhor RNA obtida. A terceira etapa consistiu na análise e validação dos resultados, realizando um cruzamento entre o mapa classificado visualmente e o mapa classificado pela Rede Neural escolhida. Utilizou-se o índice Kappa para avaliar o desempenho da RNA, uma vez que o uso desse coeficiente é satisfatório na avaliação da precisão de uma classificação temática. O resultado obtido foi superior aos resultados encontrados na literatura, com um índice Kappa de 0,558 para o relevo mais movimentado e 0,602 para o relevo menos movimentado

Simulação da quantidade máxima de domicílios permitida por quadras em Belo Horizonte

O artigo propõe uma metodologia de simulação da quantidade máxima de domicílios comportada por cada quadra do município de Belo Horizonte. Os parâmetros utilizados na simulação foram extraídos das informações cadastrais da Prefeitura, associadas com os resultados dos Censos 2000 e 2010. A simulação é desenvolvida a partir de uma base georreferenciada das quadras do município, construída a partir do mapeamento dasimétrico da distribuição domiciliar na capital mineira em 2011. Em um segundo momento, é realizada a simulação do limite máximo de novos domicílios permitidos pelas leis municipais, caso todos os lotes vagos sejam ocupados em sua capacidade máxima e caso todas as edificações com potencial de demolição cedam lugar a novos edifícios residenciais também construídos em sua capacidade domiciliar máxima. Os resultados mostram qual seria o máximo de domicílios que poderia vir a se instalar em Belo Horizonte no futuro. Estas informações servem como insumo para os dados de projeções demográficas de pequenas áreas, ao apontar onde a expansão e o adensamento domiciliar podem ocorrer, bem como o limite máximo suportado em cada quadra. De forma complementar, são indicados caminhos para discutir os limites potenciais da ocupação urbana de Belo Horizonte, as áreas preferenciais de adensamento e suas implicações para o planejamento

Interoperability through Web Services: Evaluating OGC Standards in Client Development for Spatial Data Infrastructures

Interoperability is one of the most important challenges related to GIS. Through the last years, research on interoperability has evolved from the simple off-line exchange of standardized-format files, through the establishment of spatial data clearinghouses, and to the first initiatives in the treatment of semantic aspects of data. The Open Geospatial Consortium (OGC) has proposed a number of standards to that respect, with the intention of promoting interoperability through the use of services. However, issues regarding fault tolerance, server-independent implementation, delayed-time transactions, privacy, and others reflect the need for further study and discussion. This paper discusses the current status of service-oriented architectures as applied to interoperable GIS, or, more specifically, to the implementation of local spatial data infrastructures (LSDI). A prototype designed to test the services abstract model by simulating a real-world use case is presented. Our conclusions indicate that some improvements may be helpful in the development of GIS/LSDI clients, as well as in the communication between thin clients and servers, supporting delayedtime transactions through asynchronous communication, and enabling clients to support fault-tolerant mechanisms without provider-dependent solutions.Pages: 193-20

Local Spatial Data Infrastructures Based on a Service-Oriented Architecture

Sharing geographic information is an essential activity which has been sought since the early days of GIS, mostly due to the cost of information collection and maintenance. Having once depended on the establishment of data transfer standards, sharing initiatives gradually evolved towards the creation of clearinghouses, Web resources that centralize links to various GI sources, but are still data-oriented. The current focus on spatial data infrastructures changes that, by establishing a service-oriented view, thus allowing for the creation of shared, distributed, and interoperable environments through Web services. This paper explores, in a preliminary fashion, such an architecture as applied to distributed geographic applications, focusing on the potential for local services and local uses, and proposing specialized services deemed essential for urban-scale applications.Pages: 30-4

Múltiplas representações em aplicações urbanas de sistemas de informação geográficos

Considering the costs and the effort associated with the construction of geographic databases, it is important to search for instruments that increase GIS usefulness through data sharing among different user groups, each one of them with a particular set of applications. However, distinct applications often have diverse perceptions of reality, and therefore work with different sets of concepts about the same geographic entity. These differences often require more than one representation for each geographic entity. Thus, if several applications share the same geographic database, the GIS must take over the responsibility to allow multiple representations for each geographic entity, each one of them adequate for a group of applications. This need is particularly important in the case of urban GIS applications, in which there is a wide variety of information classes and potential users, each with its particular needs regarding the representation of the objects. This article presents an analysis of the multiple representations problem in GIS, indicating the need for this feature in urban applications through examples. Alternatives are discussed, and potential problems for the implementation of this feature in GIS are indicated

Identificação de perfis de torcedores no Twitter

O objetivo deste trabalho é investigar a existência de padrões de torcedores no Twitter, centrando a análise nas características de espaço e tempo de mensagens de fãs, quando relacionados a seu time de futebol, propondo a uma relação com os eventos que compõem o campeonato

A Flexible Addressing System for Approximate Geocoding

One of the most important features in an urban geographic information system is the ability to locate addresses, in any form employed by the population, in a quick and efficient way. From an organized set of georeferenced address data, local governments, infrastructure companies, and the various agents that need to work in urban spaces can reliably and precisely locate points of their interest, in fields of application as diverse as public health services, crime fighting, product distribution, postal delivery and many others. This activity is known as geocoding, which can be defined as the process of locating points on the surface of the Earth from alphanumeric addressing data associated to events. This paper shows how geocoding can be implemented over incomplete and possibly inaccurate addressing data (which is the prevailing situation in Brazilian cities) and how users can benefit from the results of such a process. A geocoding quality indicator is proposed, with the intention of providing an indication of the degree of certainty that is associated with each individual result of the geocoding process. This indicator can then be used in spatial analysis, by giving analysts the opportunity to include the uncertainty associated with the data in their work. This project is under development, and a set of (as yet unimplemented) geocoding tools is proposed and described in the paper