Dams are structures built for controlling the flow of water for many useful purposes such as water supply, power generation, retention of mining and industrial waste, as well as recreation and flood control. However, they bring together some risk of dam body collapse causing damage for the dam downstream areas. Therefore, hypothetical dam break studies which provide mapping of areas potentially attainable in the event of a rupture are especially important for planning actions aiming minimization of associated losses. The aim of this research is to assess the degree of adherence or similarity between flood maps obtained by simulation studies and those effectively obtained from the collapse itself occurred in Dam I owned by Vale SA on January 25, 2019. The study focuses mainly on comparing the effects over the simulated flood maps caused by use of different representation of dam downstream topography relief, namely Shuttle Radar Topography Mission (SRTM), Advanced Land Observing Satellite from Alaska Satellite Facility (ALOS_ASF) and Airborne Laser Scanning (ALS) models. The simulations were performed using the HEC-RAS software developed by the US Army Corps of Engineers considering hypothesis of strong influence of relief in flood mapping results. In this way, three simulation tests were carried out for evaluation and discussion. In the first simulation, the digital terrain model derived from ALS was used. The second simulation was carried out associating the digital surface model ALOS_ASF with a spatial resolution of 12.5 m. Finally, the SRTM digital elevation model with 30 m spatial resolution provided by the United States Geological Survey (USGS) was used in third simulation. Results showed better adherence to simulations using data from ALS. This was verified by visual analysis over high resolution orthorectified images and by calculating statistics indicators such as the (F) index. Conclusions pointed out that flood patches resulting from simulation are critical tools for taking actions involving areas and populations to be affected, so the best relief model technologies like ALS data should be used in simulation.

Geological Mapping, one of the mineral exploration activities, is associated with risks and investments and is vital to the creation of value in mining. Solutions, which guarantee the reliability of resources and reserves, are in constant development. GIS -Geographic Information Systems have proven to be one of the most decisive of the technologies involved in the process, which ensures the integration of data and information and greater objectivity in identifying value. Considering that ore bodies need to be considered in the entire three-dimensional complexity of their shapes, geovisualization would be more effective if it were conducted in three dimensions (3D) with the association of realistic images, providing a representation in virtual reality -VR. The association between GIS and VR will lead to a new benchmark in mineral exploration geological research activities, in the acquisition of field data and in the analysis, discussion and visualization of exploration results. As such, the objective of this article is to identify the parts of the process, which can be improved using a geotechnological approach, and includes a pragmatic assessment of mineral exploration, of the activities to be improved and the planning, providing an insight into the practical effects of such improvements, as the geological mapping, which could be changed from 2D to 3D the representation of the results, with implicit modeling.

IBGE: saberes e práticas territoriais A atuação do IBGE na evolução da cartografia civil no BrasilThe role of IBGE in civil cartography development in Brazil La actuación del IBGE en la evolución de la cartografía civil en Brasil Le rôle de l'IBGE dans l'évolution de la cartographie civile au Brésil

In the light of the technological transformations that have been occurring in the field of Remote Sensing, the objective of this study was to evaluate the feasibility and the quality of the results that could be achieved in the topographic modeling of the terrain with a Remotely Piloted Aircraft Systems (RPAS) survey in open-pit mines. The mining activity imposes the recurring topographic survey of mined and service areas that require volume evaluation in an interval of at least one month. In this context, the expectation of adopting traditional remote sensing methods for surveying, instead of land surveys, has always been great. The restrictions on the adoption of the conventional photogrammetric or airborne laser scanning (ALS) methods were related to the need for recurring surveys, which are never simple with the use of manned aerial platforms. In this context, the RPAS opens a window of opportunity that should not be ignored, being the main reason for the case study reported here. The essential data set of the research results from the direct confrontation between two digital terrain models: the first obtained with the RPAS survey executed in 2016 and another one of the same area obtained by a laser aerial survey performed in 2012, which was considered as a quality benchmark. The results recommended that the implementation of mapping solutions with RPAS consider the quality constraints of the photogrammetry in order to improve final results with the theoretical and operational knowledge that underpin the photogrammetric process.

As Áreas de Preservação Permanente (APP), de acordo com o terceiro Código Florestal de 2012, são espaços territorialmente protegidos com funções de preservar os recursos hídricos, garantir a estabilidade geológica, manter a biodiversidade e promover o bem-estar das populações. Entretanto, devido ao crescimento acelerado dos núcleos urbanos brasileiros com pouco planejamento por parte dos poderes públicos, as cidades passaram a conviver com diversos problemas ambientais devido ao uso irregular de tais espaços. Nesse contexto, este trabalho tem por objetivo analisar os conflitos de uso e cobertura da terra provenientes da ocupação irregular em Áreas de Preservação Permanente (APP) no município de Niterói. Para alcançar tal objetivo foi gerado o Modelo Digital de Elevação Hidrologicamente Condicionado (MDEHC) e utilizada a base cartográfica do IBGE em 1:25.000 de modo a mapear as APP. A seguir foi elaborado um mapa de uso e cobertura da terra usando imagem RapidEye e o método Máxima Verossimilhança obtendo uma exatidão global pelo coeficiente Kappa de 0,806. As APP ocupam 13,98% do município de Niterói, com destaque para a APP de faixa marginal com uma área de 11,54 km² ou 8,63%. Desse total, aproximadamente 69% das APP estão devidamente conservadas, enquanto 31% estão indevidamente ocupadas.