Integrating remote sensing and geospatial big data for urban land use mapping: a review

Remote Sensing (RS) has been used in urban mapping for a long time; however, the complexity and diversity of urban functional patterns are difficult to be captured by RS only. Emerging Geospatial Big Data (GBD) are considered as the supplement to RS data, and help to contribute to our understanding of urban lands from physical aspects (i.e., urban land cover) to socioeconomic aspects (i.e., urban land use). Integrating RS and GBD could be an effective way to combine physical and socioeconomic aspects with great potential for high-quality urban land use classification. In this study, we reviewed the existing literature and focused on the state-of-the-art and perspective of the urban land use categorization by integrating RS and GBD. Specifically, the commonly used RS features (e.g., spectral, textural, temporal, and spatial features) and GBD features (e.g., spatial, temporal, semantic, and sequence features) were identified and analyzed in urban land use classification. The integration strategies for RS and GBD features were categorized into feature-level integration (FI) and decision-level integration (DI). To be more specific, the FI method integrates the RS and GBD features and classifies urban land use types using the integrated feature sets; the DI method processes RS and GBD independently and then merges the classification results based on decision rules. We also discussed other critical issues, including analysis unit setting, parcel segmentation, parcel labeling of land use types, and data integration. Our findings provide a retrospect of different features from RS and GBD, strategies of RS and GBD integration, and their pros and cons, which could help to define the framework for future urban land use mapping and better support urban planning, urban environment assessment, urban disaster monitoring and urban traffic analysis

Social media and GIScience: Collection, analysis, and visualization of user-generated spatial data

Over the last decade, social media platforms have eclipsed the height of popular culture and communication technology, which, in combination with widespread access to GIS-enabled hardware (i.e. mobile phones), has resulted in the continuous creation of massive amounts of user-generated spatial data. This thesis explores how social media data have been utilized in GIS research and provides a commentary on the impacts of this next iteration of technological change with respect to GIScience. First, the roots of GIS technology are traced to set the stage for the examination of social media as a technological catalyst for change in GIScience. Next, a scoping review is conducted to gather and synthesize a summary of methods used to collect, analyze, and visualize this data. Finally, a case study exploring the spatio-temporality of crowdfunding behaviours in Canada during the COVID-19 pandemic is presented to demonstrate the utility of social media data in spatial research

Geo-Information Harvesting from Social Media Data

As unconventional sources of geo-information, massive imagery and text messages from open platforms and social media form a temporally quasi-seamless, spatially multi-perspective stream, but with unknown and diverse quality. Due to its complementarity to remote sensing data, geo-information from these sources offers promising perspectives, but harvesting is not trivial due to its data characteristics. In this article, we address key aspects in the field, including data availability, analysis-ready data preparation and data management, geo-information extraction from social media text messages and images, and the fusion of social media and remote sensing data. We then showcase some exemplary geographic applications. In addition, we present the first extensive discussion of ethical considerations of social media data in the context of geo-information harvesting and geographic applications. With this effort, we wish to stimulate curiosity and lay the groundwork for researchers who intend to explore social media data for geo-applications. We encourage the community to join forces by sharing their code and data.Comment: Accepted for publication IEEE Geoscience and Remote Sensing Magazin

A New Picture of the City: Volunteered Geographic Image Information and the Cities

The urbanisation process continuously influences human life, causing long-term challenges for the planning and management of urban areas. In recent years, with the emergence of new forms of data and advances in techniques, the ways of managing and governing this process have evolved and formed a new research field: urban analytics. A growing number of human behaviours can be traced through quantities of data, which enables attributes of the urban environment to be managed more efficiently, potentially beneficial to complex decision-making processes by stakeholders. As such, how to extract useful information from new data and provide more suitable methods requires careful consideration. The question of how human activity relates to the built environment has been an important topic in the sensing of cities. Existing ways to perceive the city either focus on environmental aspects that cover historical, social, or cultural dimensions of urban space through surveys, interviews, or mobility data (e.g., social media data), or extract visible features from georeferenced images to gain perceptions of the city. However, both approaches are often disconnected and lack dynamic consideration. The main aim of this thesis is to address these challenges and gaps within urban analytics. It develops a methodological framework to leverage user-generated geotagged images and modern analytical techniques to obtain insights. Such framework is designed to mine spatial, temporal and image attributes of the Flickr images, which combines multiple dimensions including spatiotemporal dynamic analysis, computer vision models, summary statistics, and varying machine learning algorithms that allow understanding of human interactions with the built environment. The overall analysis and results enrich our current understanding of how user-generated urban pictures represent but also shape the city. This is especially important given the growing popularity of volunteered geographic information and urban analytics over the last decade. Their rapid growth has facilitated debates worldwide, but there is still a large potential of volunteered geographic information such as geotagged image information which has been underestimated in most circumstances. The findings presented in this thesis offer richer evidence that aims to help the improvement of strategic planning systems, and empowering policymakers to make smarter decisions in terms of urban governance

Valorização automática de imóveis urbanos através da interpolação de dados comparativos geoespaciais raster

Os financiamentos de imóveis residenciais do Banco do Brasil envolvem hoje avaliações de imóveis que são executadas presencialmente por engenheiros e arquitetos credenciados pelo Banco do Brasil, para a realização de serviços de vistorias e elaboração de laudos técnicos de avaliação. Essas avaliações abrangem tempo e custo considerável para a execução, uma vez que demandam estudos para preparação do laudo e freqüentes deslocamentos, além da hospedagem por parte de credenciados. Considerando as centenas de milhares de dados completos de imóveis residenciais que o Banco sempre teve das operações antigas, um método de valoração remota utilizando fotos de satélite, informações georreferenciadas de imóveis, modelos geoestatísticos e ferramentas de websig possibilitaria uma avaliação rápida, com qualidade, dentro das normas técnicas, e até dez vezes mais barata, possibilitando que os próprios engenheiros e arquitetos do Banco apurem o valor dos imóveis residenciais, a partir da análise de dezenas de modelos com boa acurácia que informem o valor unitário de cada tipologia de imóvel em dezenas de cidades brasileiras, visando diminuir o tempo e o custo do processo de avaliação para o Banco e o cliente, principalmente no que tange aos imóveis populares subsidiados em futuros programas do Governo Federal, a partir de 2023, com o retorno do Presidente Lula, e do Programa Minha Casa Minha Vida, possibilitando milhões de economia anuais ao Banco, ao governo federal e ao povo brasileiro, este último, o verdadeiro dono do Banco do Brasil, resgatando o valor de espírito público, presente na missão do Banco, garantindo a função social que os bancos públicos devem representar em um dos países com o maior desequilíbrio social do mundo. Esta dissertação possibilitará resultados de milhões de euros de economia ao Banco do Brasil, mas que também deverá ser revertido ao Governo Federal, e ao povo brasileiro, maior acionista e verdadeiro dono, deste patrimônio chamado Banco do Brasil, criado pelo digníssimo Rei Português Dom João VI, em 1808, sendo a empresa mais antiga do Brasil, e sempre ao serviço do Povo Brasileiro, como nunca antes na história desse país.Banco do Brasil's residential property financing currently involves real estate appraisals that are executed by engineers and architects accredited by Banco do Brasil, to carry out inspection services and prepare technical appraisal reports. It´s necessary much time and cost for these appraisals, and they demand studies for the preparation of the report and frequent displacements, in addition to accommodation by accredited professionals. Considering the hundreds of thousands of complete residential property data that the Bank has from past operations, a remote valuation method using satellite photos, georeferenced property information, geostatistical models and webgis tools would enable a quick, quality valuation within technical standards, and up to ten times cheaper, allowing the Bank's engineers and architects themselves to determine the value of residential properties, based on the analysis of dozens of models with good accuracy that inform the unit value of each property typology in dozens of Brazilian cities, aiming to reduce the time and cost of the evaluation process for the Bank and the client, especially with regard to popular properties subsidized in future Federal Government programs, starting in 2023, with the return of President Lula, and the “My Home My Life Program”, enabling millions of annual savings to the Bank, the government and to the Brazilian people, the latter, the true owner of Banco do Brasil, rescuing the value of public spirit, present in the Bank's mission, resurrecting the social function that public banks should represent in one of the countries with the greatest social imbalance in the world. This dissertation will make possible results of millions of euros of savings to Banco do Brasil, but which should also be reverted to the Federal Government, and to the Brazilian people, the largest shareholder and true owner, of this heritage called Banco do Brasil, created by the dignified Portuguese King Dom João VI, in 1808, being the oldest company in Brazil, and always at the service of the Brazilian People, as never before in the history of that country