Abstract: Due to waterway transport efficiency, mainly for commercial trades, the use of sea/river routes has grown recently. So, the importance of producing high quality nautical charts stands out. A nautical chart is the hydrographic survey final product and its accuracy depends on data quality collected, primarily of the vertical quality (depth). In this sense, despite the theoretical and practical difficulty in obtaining homologous points in hydrographic surveys, even when performing check lines, bathymetric data must always be delivered with a statistically proven confidence level. Thus, this study has two main objectives: i) to propose a method, called Point to Point (P2P), for obtaining “homologous points” for hydrographic surveys carried out with multibeam systems, without resorting to mathematical and/or statistical interpolations, called Point to Point (P2P); ii) to quantify the magnitude of the difference between the statistical evaluation using check lines (CL) and by overlapping successive sounding lines (SL), applying the P2P method. The results showed that P2P is easy to application, provide low computation effort, is robust and consistent. Besides that, was possible to applied successive regular lines to get a validation of the hydrographic survey.

Abstract: This work presents a new methodology for extracting 3D homologous points from a DEM/DSM for relative evaluation of positional accuracies, from terrain features such as ridgelines and hydrography. Firstly, it extracts 3D intersection points between the linear features and then it performs a selection of these homologous points. A discussion regarding the spatial resolution effect of the DEM/DSM on the proposed methodology is carried out. As case study, the planimetric and altimetric positional accuracies evaluation of SRTM (X-band) and Aster GDEM (version 2) DSMs was conducted using, as reference, a DSM obtained via photogrammetry. The SRTM and Aster GDEM (version 2) DSMs showed similar classifications, that is, Class A for the altimetry and Class B for the planimetry at the 1:100,000 scale, according to the Brazilian technical standard of positional accuracy.

Abstract Currently, during the operation in shallow waters, scanning systems, such as multibeam systems, are capable of collecting thousands of points in a short time, promoting a greater coverage of the submerged bottom, with consequent increase in the detection capacity of objects. Although there has been an improvement in the accuracy of the depths collected, traditional processing, that is, manual, is still required. However, mainly due to the increased mass of data collected, manual processing has become extremely time-consuming and subjective, especially in the detection and elimination of spikes. Several algorithms are used to perform this task, but most of them are based on statistical assumptions hardly met and/or verified, such as spatial independence and normality. In this sense, the goal of this study is to present the SODA (Spatial Outlier Detection Algorithm) methodology, a new method for detection of spikes designed to treat bathymetric data collected through swath bathymetry systems. From computational simulation, promising results were obtained. SODA, in some cases, was capable to identify even 90% of spikes inserted on simulation, showing that the methodology is efficient and substantial to the bathymetric data treatment.

Abstract: The amount of data produced in an echosounder has increased dramatically with scanning systems such as multibeam echo sounders and interferometric sonars, providing a considerable improvement in the submerged terrain representation, especially when it comes to detecting hazardous objects to the navigator. However, the available processing algorithms did not come along with this evolution; manual processing or, at least, constant intervention is usually necessary, which makes this task arduous with a high degree of subjectivity. In addition, statistical inconsistencies do not appear to be uncommon in most of the algorithms and filters available. Thus, SODA (Spatial Outliers Detection Algorithm) was recently presented, being a methodology directed, at first, to echosounder data treatment. Considering this, this article aims to evaluate the SODA efficiency for real data treatment from a multibeam sonar. SODA, in some cases, was capable to identify up to 74% of spikes with the δ-Method, which means that this technique detected 28 out of the 38 confirmed spikes in the data set, reassuming the methodology strength regarding the search for spikes in echosounder data.

Resumo: As demandas por dados geoespaciais referentes à malha viária são constantes, visto a gama de aplicações que necessitam desse tipo de dado. Destaca-se a importância destes dados nos ciclos de atualização de bases cartográficas, pois podem ser obtidos utilizando processos automatizados de extração de feições em imagens digitais, de forma mais precisa, rápida e menos onerosa, comparados aos métodos tradicionais. Nesse sentindo, este trabalho teve como objetivo a extração da malha viária em imagens RapidEye por meio do desenvolvimento de uma metodologia semiautomática híbrida, utilizando técnicas de classificação de imagem baseada em objetos e operadores morfológicos. A metodologia foi testada em três áreas distintas, com imagens adquiridas em épocas diferentes e o processo de extração avaliado por meio de métricas obtidas da correspondência linear. Foram alcançados em termos de corretude e completude os valores de 92,23% e 85,15% para a área 1, os valores de 79,16% e 81,06% na área 2, e os valores de 82,05% e 92,22% para a área 3, respectivamente. Os resultados demonstraram que o método proposto apresentou bom desempenho para a extração semiautomática de vias em imagens RapidEye, sendo uma alternativa para auxiliar na aquisição e atualização de base de dados da malha viária.

Abstract: The demand for geospatial data concerning road network is constant, due to the wide variety of application which needs this type of data. It stands out the importance of this data in cartography update cycles, that can be obtained using automated processes of feature extraction in digital images, which are more accurate, fast and less costly than the traditional methods. In this sense, this work aimed the road network extraction from RapidEye satellite imagery, by developing a hybrid methodology using techniques of object-based image classification and morphological operators. The methodology was tested in three different sites, with images acquired in distinct dates, and the extraction process was evaluated through metrics obtained from the linear matching procedure. By the proposed extraction process, were achieved in terms of correctness and completeness the values of 92.23% and 85.15% for test site 1, the values of 79.16% and 81.06% for test site 2, and the values of 82.05% and 92.22% for test site 3, respectively. The results shown that the proposed methodology presented a good performance for semi-automatic road network extraction from Rapideye images, representing an alternative to auxiliary road network database acquisition and updating.

Atualmente a validação da qualidade das informações cartográficas tem sido um tema cada vez mais evidente e de extrema importância. Com o surgimento da Infraestrutura Nacional de Dados Espaciais (INDE), surgiram diversas especificações técnicas com a finalidade de regulamentar e padronizar os inúmeros processos relacionados à produção cartográfica nacional. Nesse contexto, o objetivo do presente estudo é avaliar a acurácia posicional planimétrica de uma ortofoto gerada a partir de um sensor embarcado em uma plataforma VANT, através da aplicação dos métodos de feições pontuais e lineares, de acordo com o padrão de acurácia posicional brasileiro (Decreto-lei 89.817 aliado à ET-ADGV), considerando como referência um levantamento topográfico executado utilizando a tecnologia GNSS (Global Navigation Satéllite System) e método de posicionamento RTK (Real Time Kinematic). Os resultados alcançados demostram que tanto o método de feição linear (método Buffer Duplo) quanto o método de feição pontual apresentaram resultados similares, obtendo-se segundo o Decreto-lei nº 89.817 em concordância com a ET-ADGV classificação classe B para a escala 1:1000.

Currently the validation of the quality of cartographic information has been an issue ever more evident and important. With the emergence of the National Spatial Data Infrastructure (INDE) in Brazil, there were several technical specifications in order to regulate and standardize the many processes related to national cartographic production. In this context, the objective of this study is to evaluate the positional planimetric accuracy of orthophoto generated from an embedded sensor on a UAV platform by applying methods of point and linear features, according to the Brazilian standard for positional accuracy (Decree Law 89 817 combined with ET-ADGV), considering as a reference survey performed using RTK GNSS positioning technology. The results obtained demonstrate that both linear feature method (Double Buffer method) and the pontual feature method showed similar results, obtaining classification Class B to scale 1: 1,000, according to the Decree Law No. 89,817 / ET-ADGV

Atualmente, tem-se aumentado a preocupação com a avaliação da acurácia posicional em dados espaciais, principalmente em dados com informações altimétricas. Contudo, vários trabalhos avaliam apenas a componente altimétrica, desconsiderando a acurácia posicional planimétrica. Assim, este trabalho tem como objetivo avaliar a acurácia posicional planimétrica dos principais MDSs disponíveis gratuitamente para o Brasil, como os modelos SRTM (banda C e X), Aster GDEM versão 2 e TOPODATA. Para a avaliação da acurácia posicional planimétrica dos MDSs, fez-se a extração de feições características do terreno como linhas de cumeadas e linhas de hidrografia numérica. Em seguida, de posse destas feições lineares, aplicou-se o método do Buffer Duplo para avaliar a acurácia posicional planimétrica de acordo com o padrão definido no Decreto-lei n° 89.817/ET-ADGV. Para a comparação destes modelos, utilizou-se como referência um MDS, na escala de 1:25.000, obtido do sensor ALOS/PRISM. Os resultados da avaliação posicional planimétrica apresentaram Classe C na escala 1:100.000 para os MDS SRTM-X e Aster GDEM; para os MDS TOPODATA e SRTM-C, as classificações obtidas foram Classe B e Classe C na escala de 1:250.000, respectivamente

Currently, the concern over positional accuracy assessment in spatial data has grown, primarily in data with altimetric data information. However, several studies only assess the altimetric component, disregarding the planimetric positional accuracy. Thus, this work aims to evaluate the planimetric positional accuracy of the main MDSs available for free in Brazil, such as SRTM (band C and X), Aster GDEM version 2 and TOPODATA models. To evaluate the planimetric positional accuracy ridge lines and numerical hydrography lines were extracted as terrain characteristics. Then, in possession of these linear features, the Double Buffer method was applied to evaluate the horizontal accuracy according to the standards defined in Decree-Law n° 89,817/ET-ADGV. To compare these models an MDS obtained from ALOS/PRISM sensors, on a scale of 1:25,000, was used as a reference . The results of the planimetric positional evaluation were class C at 1:100,000 scale for the MDS SRTM-X and Aster GDEM; for the MDS TOPODATA and SRTM-C, the obtained classifications were class B and class C on a scale of 1:250,000, respectively.

Nas últimas duas décadas, o uso de feições lineares tem sido frequentemente investigado no controle de qualidade cartográfica, sendo que diversos métodos foram propostos para tal finalidade. Neste sentido, o presente trabalho tem como objetivo descrever os métodos da Banda Épsilon (Método das Áreas), do Buffer Simples, do Buffer Duplo, da Distância de Hausdorff e da Influência do Vértice na avaliação da acurácia planimétrica através de feições lineares, utilizando como padrão o Decreto-lei nº 89.817 aliada à ET-ADGV, e ao final, compará-los com o método tradicional por pontos. Para tanto, foi avaliada a acurácia posicional planimétrica de uma ortoimagem Ikonos, onde os resultados obtidos mostraram que os métodos da Banda Épsilon, Distância de Hausdorff e Influência do Vértice apresentaram resultados similares, obtendo-se classificação Classe B na escala 1:10.000. Já os métodos Buffer Simples e Buffer Duplo apresentaram resultados semelhantes ao método tradicional por pontos, que por sua vez, foram mais restritivos que os métodos anteriormente citados, classificando a ortoimagem como Classe C na escala 1:10.000.

In the past two decades, the use of linear features has often been investigated in cartographic quality control, and various methods have been proposed for such a purpose. In this sense, this paper aims at describing the methods of the Epsilon Band (areas' method), Simple Buffer, Double Buffer, Hausdorff's Distance and Vertex's Influence in the assessment of planimetric positional accuracy by means of linear features, using as standard the Decree-Law number 89,817 / ET-ADGV, and after this, compare them with the traditional method by points. On the one hand, planimetric positional accuracy was evaluated in a orthoimage Ikonos, where results showed that the methods of the Epsilon Band, Hausdorff's Distance and Vertex's Influence presented similar results, obtaining "class B" rating on the scale 1: 10,000. On the other hand the methods Simple Buffer and Double Buffer presented similar results to traditional method by points, which in turn were more restrictive than the previously mentioned methods, classifying the orthoimage as "Class C" in 1: 10,000 scale.