Altimetry Quality of SRTM and ASTER GDEM Products for Areas with Different Reliefs

Hydroelectric power plants cause impacts that are usually estimated by an indicator, the hydroelectric power generation per hectare of flooded area. And, although entrepreneurs use quality-declared cartographic bases to comply with the standards, at the project stages of a hydroelectric plant it is not a priori determined whether the altimetry tolerance of such bases is sufficient to ensure that the impacts will not increase, which in the project consolidation becomes a huge problem. This work aims to define the altimetry quality of SRTM Digital Elevation Models (DEM) and ASTER GDEM and whether they are a priori sufficient to simulate the flood level of hydroelectric power plants in different reliefs. To accomplish this objective, a morphological method of assessment of the DEM quality was developed, through Geographic Information Systems (GIS), so that the altimetry information generated by the models and field surveys, when compared, would show their actual differences also in relation to their areas. To this end, two study areas were used: one with a slightly undulated relief and the other with undulated relief. To validate the models, quality assessments were carried out: based on points, according to the Brazilian Map Accuracy Standard (MAS) and STANAG 2215;and based on surfaces, according to Article 500 of the Brazilian Civil Code and the morphological method. At the end, practical applications relating to the M&P indicator and hydroelectric power plants projects were also carried out. The results presented demonstrate that the quality of an SRTM DEM when used in undulating or gently undulating reliefs can be used up to 1:80,000 scale. Already for DEM ASTER under the same conditions, it is possible to use on the scale 1:100,000. In DEM SRTM and DEM ASTER, after removing the systematic error (−7.3 m) and (−6.2 m), respectively, the quality between 65% and 79% is verified for DEM SRTM and 53%, and 68% for DEM ASTER for common areas in flood level simulation.

Human Visual Acuity in Analysis of Intervention in the Landscape of Coxilha Rica/Brazil

The Drovers’ Paths are remnants of important land access roads from Rio Grande do Sul to São Paulo at the time of Colonial Brazil. They were built and used between the 18th and 20th centuries, particularly in the region of Coxilha Rica. The main objective of this research is to develop a method for decision-making applied to the territorial landscape management in the Coxilha Rica. The method consisted of generating criteria to map the visibility spot reached from the main selected points;define the human visual acuity, realize bibliographic research, use cartographic and historical documents, inter-views, as well as field surveys that enabled the identification, characterization and mapping of historical farms and drovers’ paths. After data processing, the information was entered into the cartographic database;the data were cross-checked and analysis was made of the visibility of the surrounding farms and stone-walled corridors. Quality assessments showed that, with the visibility polygons, and through the use of cartographic tools, we could cross-check between different levels of information and analyze landscape intervention alternatives in order to minimize environmental impacts. When applying the method in the Coxilha Rica it was possible mapping the visibility polygon, taking human visual acuity into consideration, based on historical farms and stone-walled corridors;and making spatial analyses to explore alternatives to intervention (installation of power transmission systems) in order to preserve the scenic environment of the region. In the end, the decision was by does not construct the system.

Remote Sensing Applied to Regional-Scale Mapping of Solar Potential—Case Study on Florianopolis Island

Satellite imagery is used for many activities in different areas of the planet, including searching for alternative and sustainable sources to meet growing energy demand to reduce greenhouse gas (GHG) emissions. One way to minimize these effects and expand energy parks is to encourage local generation through the use of renewable sources, such as solar energy, which is free and affordable in many regions of the planet, but that in Brazil is not yet a reality. In order to make an assertive decision when installing a solar power system, one needs to use tools that involve remote sensing and geographic information systems (GIS), and compile information and variables that are relevant to the subject of solar power generation and take into account the inherent geographic space. In this context, the main objective of this work is to develop a GIS model to identify areas with solar potential on a regional scale using active remote sensor images and previously available solar models. To validate the model, this study used an area on the island part of the city of Florianópolis in Santa Catarina State—Brazil, which suffers from repeated climatic events which cause long power cuts, as its distribution occurs by air all over the island. Through the “solar analist” function of ArcGIS and the matrix bases derived from the Digital Model of the Space Shuttle Topography Mission (SRTM) with 30 m of spatial resolution and the supervised classification of panthromatic and multispectral images fused from LandSat 8 satellite, were generates indicative maps of the areas with solar potential. The results pointed to a high solar potential in the all year and that could be better explored by public managers and also by individual consumers.