Avaliação da acurácia posicional de vértices obtidos por imagem de sensor orbital e aerofotogrametria para fins de georreferenciamento de imóveis rurais

Em sua grande maioria, o georreferenciamento de imóveis rurais tem sido realizado somente com o levantamento geodésico (LG) por meio de receptores GNSS. Porém, é possível realizá-lo por meio de imagens de satélites e imagens aerotransportadas. A utilização de imagens orbitais ou aerotransportadas pode reduzir o tempo de serviço e auxiliar em limites inacessíveis e naturais. O maior problema em realizar o georreferenciamento utilizando imagens está em atender às precisões exigidas pelo Instituto Nacional de Colonização e Reforma Agrária (INCRA), em razão do imageamento ser menos preciso que o levantamento geodésico. Outra dificuldade está em identificar feições que se encontram sob matas. Entretanto, no mercado existem imagens de satélite de alta resolução espacial e também existe a possibilidade de obtenção de imagens coletadas por aeronaves remotamente pilotadas (ARP) com altíssima resolução espacial que podem atender as exigências. Deste modo este trabalho tem como objetivo avaliar as feições obtidas por três imagens, uma WorldView-3, uma PlanetScope e por uma ortofoto de ARP, sendo estas três comparadas e avaliadas a partir do LG por meio de receptores GNSS. Entre os conjuntos de dados utilizados o melhor resultado de acordo com a classificação normativa do INCRA foi a ortofoto gerada pelo levantamento aerofotogramétrico, pois atendeu à precisão para os vértices artificiais, naturais e vértices inacessíveis. No entanto, a imagem WorldView-3 apresentou o pior resultado na classificação, pois não atendeu nenhum dos tipos de vértices. Entre os três conjuntos de dados utilizados recomenda-se utilizar o levantamento aerofotogramétrico para realizar o georreferenciamento de imóveis rurais. Evaluation of the positional accuracy of features obtained by images of orbital sensors and airborne for georeferencing of rural propertiesA B S T R A C TConcerning methods of positioning the georeferencing of rural properties, it stands out the topographical and geodetic surveys. However, it is possible to make through remote sensing (images of orbital sensors and airborne). The use of orbital or air-bone images can reduce service time and help in inaccessible areas, such as unreachable and natural limits. The most significant difficulty of the georeferencing using images is to meet the required accuracy by the National Institute of Colonization and Agrarian Reform (INCRA). However, there are high spatial resolution satellite images are now available. There is the possibility of getting the images collected by remotely piloted aircraft (RPA) with a very high spatial resolution that meets the requirements. This work aims to assess the features obtained by three images, a WorldView-3, a Planet Scope, and an RPA orthophoto. These three are being compared and evaluated from a geodetic survey and subsequently classified according to the cartographic precision standard of INCRA. The best dataset for the normative of INCRA was the orthophoto generated by RPA because it met the precision for artificial, natural vertices and inaccessible vertices. However, the WV-3 image had the worst result in the classification because it did not meet consistent accuracy to any of the vertices' types. Between the three data sets used, the one that best suits the specifications of georeferencing of rural properties were the images airborne.Key words: Remote Sensing, INCRA Rules, Aerophotogrammetric Survey, Cartographic Accuracy Standard.

About the approximation of the tunnel lining deformations according to the measurement results

The article deals with the approximation of the displacements of the points of the tunnel lining contour, obtained, for example, by geodetic survey. In the future, the processed data can be used to calculate the internal forces in the tunnel lining, which will help in monitoring the technical condition of the bearing structures of underground structures. In the article, calculation formulas have been obtained that allow using the measured displacements of the reference points to find the displacements of any point of the lining. Displacements are determined by approximating deformations with periodic cubic splines. To determine the coefficients of splines, it is proposed to apply the common least squares method. A method for calculating the weighting coefficients of basic functions for a spline with an arbitrary step of the nodes is presented. As an intermediate result, analytical dependences were obtained between the Cartesian coordinates of the tunnel lining points and the arc length. In this case, the design data on the radii of curvature of the lining sections and the coordinates of the points of section conjugation were used. It is assumed that the data obtained will increase the information content of the control and can be used to monitor its technical condition of underground structures at all stages of its life cycle.

A survey of storm-induced seaward-transport features observed during the 2019 and 2020 hurricane seasons

Hurricanes are known to play a critical role in reshaping coastlines, particularly on the open ocean coast in cases of overwash, but storm induced seaward-directed flow and responses are often ignored or un-documented. Subaerial evidence for seaward sediment transport (outwash, return-flow) increases our understanding of the impact hurricanes have on coastal and barrier island evolution. Towards this goal we catalog all available National Geodetic Survey Emergency Response Imagery (ERI), the National Oceanic and Atmospheric Administration’s (NOAA) collection of post-hurricane aerial imagery on the U.S East Atlantic and Gulf of Mexico coasts, for visible washout and return flow features. The most recent examples are from the North Core Banks, North Carolina, after Hurricane Dorian (2019), the Carolina coasts after Hurricane Isaias (2020), the Isles Dernieres, Louisiana, after Hurricane Zeta (2020), and the southwest coast of Louisiana, after Hurricanes Laura and Delta (2020); these include erosive scours and channels but also depositional deltas and fans on the shoreface and nearshore. Over the nearly 200 km of coastline analyzed, hundreds of seaward-flow features were identified; the density exceeds 20 per km in some areas. Individual features measure between 5 m and 500 m in both the along- and cross-shore dimensions. The extensive occurrence of these storm-induced return-flow and outwash morphologic features demonstrates that their sediment transport role may be more influential than previously thought. Based on these observations, we advocate for their inclusion in coastal change hazards classification schemes and coastal evolution morphodynamic models and propose an adoption of direction-explicit terms to use when describing return- and seaward-flow features to reduce redundant jargon and distinguish them from more frequently documented landward-flow features.

A survey of storm-induced seaward-transport features observed during the 2019 and 2020 hurricane seasons

Hurricanes are known to play a critical role in reshaping coastlines, but often only impacts on the open ocean coast are considered, ignoring seaward-directed forces and responses. The identification of subaerial evidence for storm-induced seaward transport is a critical step towards understanding its impact on coastal resiliency. The visual features, found in the National Oceanic and Atmospheric Administration, National Geodetic Survey Emergency Response Imagery (ERI) collected after recent hurricanes on the U.S. East Atlantic and Gulf of Mexico coasts, include scours and channelized erosion, but also deposition on the shoreface or in the nearshore as deltas and fans of various sizes. We catalog all available ERI and describe recently formed features found on the North Core Banks, North Carolina, after Hurricane Dorian (2019); the Carolina coasts after Hurricane Isaias (2020); the Isles Dernieres, Louisiana, after Hurricane Zeta (2020); and the southwest coast of Louisiana, after Hurricanes Laura and Delta (2020). Hundreds of features were identified over nearly 200 km of coastline with the density of features exceeding 20 per km in some areas. Individual features range in size from 5 m to 500 m in the alongshore, with similar dimensions in the cross-shore direction, including the formation or reactivation of outlets. The extensive occurrence of these storm-induced return-flow and seawardflow morphologic features demonstrates that their role in coastal evolution and resilience may be more prominent than previously thought. Based on these observations we propose clarifying terms for return- and seaward-flow features to distinguish them from more frequently documented landward-flow features and advocate for their inclusion in coastal change hazards classification schemes and coastal evolution morphodynamic models.

VLBI measurement of the vector baseline between geodetic antennas at Kokee Park Geophysical Observatory, Hawaii

We measured the components of the 31-m-long vector between the two very-long-baseline interferometry (VLBI) antennas at the Kokee Park Geophysical Observatory (KPGO), Hawaii, with approximately 1 mm precision using phase delay observables from dedicated VLBI observations in 2016 and 2018. The two KPGO antennas are the 20 m legacy VLBI antenna and the 12 m VLBI Global Observing System (VGOS) antenna. Independent estimates of the vector between the two antennas were obtained by the National Geodetic Survey (NGS) using standard optical surveys in 2015 and 2018. The uncertainties of the latter survey were 0.3 and 0.7 mm in the horizontal and vertical components of the baseline, respectively. We applied corrections to the measured positions for the varying thermal deformation of the antennas on the different days of the VLBI and survey measurements, which can amount to 1 mm, bringing all results to a common reference temperature. The difference between the VLBI and survey results are 0.2 ± 0.4 mm, −1.3 ± 0.4 mm, and 0.8 ± 0.8 mm in the East, North, and Up topocentric components, respectively. We also estimate that the Up component of the baseline may suffer from systematic errors due to gravitational deformation and uncalibrated instrumental delay variations at the 20 m antenna that may reach ± 10 and −2 mm, respectively, resulting in an accuracy uncertainty on the order of 10 mm for the relative heights of the antennas. Furthermore, possible tilting of the 12 m antenna increases the uncertainties in the differences in the horizontal components to 1.0 mm. These results bring into focus the importance of (1) correcting to a common reference temperature the measurements of the reference points of all geodetic instruments within a site, (2) obtaining measurements of the gravitational deformation of all antennas, and (3) monitoring local motions of the geodetic instruments. These results have significant implications for the accuracy of global reference frames that require accurate local ties between geodetic instruments, such as the International Terrestrial Reference Frame (ITRF).

Review of the Remetinec roundabout reconstruction project in Zagreb

A very complex problem of the main roundabout projects development concerning the solutions given in the location permit and preliminary design, as well as new knowledge about communal infrastructure is given. Based on the new geodetic survey, subsequent requirements of the audit, investors, and obtained special conditions, it was necessary to adapt the technical solutions of the preliminary design. Particularly demanding work was defining the protection of the construction pit. The solution foreseen by the preliminary design and location permit for the works to be carried out under the traffic could not have survived, because of the technological reasons for the construction of the underpass and the very complex situation with the installations at that location. These facts required a complete suspension of traffic at the site and finding solutions to the temporary traffic regulation around the site. This was an unplanned and very demanding moment, given that the daily traffic at the intersection was around one hundred thousand vehicles a day. The solution to this problem was found in the construction of a temporary road, which conducts traffic through and around the construction site, thus enabling the smooth technological and technical organization of works while simultaneously conducting public and individual traffic to and from the city.

Evaluating the Landslides Characterization and Deformation Using Multi-Temporal Uav Imageries in Northern Pakistan

The Un Manned Aerial Vehicles (UAVs) have emerged as an effective tool for mapping and evaluating the landslides dynamics. This study aims to evaluate the dynamics of the landslide using the UAV derived aerial photos and Digital Surface Model (DSM). The selected landslides are the Nara and Nokot landslides in the rough terrain of Balakot, north Pakistan. The UAV survey was carried in April and August 2019 for Nara and Nokot landslides in Balakot. The images were processed in the Pix4D mapper to compute the orthomosaic and DSMs. The Ground Control Points (GCPs) collected in the geodetic survey with the Global Navigation Satellite System (GNSS) using Post Processing Kinematic (PPK) were used to accurately co-register and orthorectify the UAV imageries. The derived DSMs were analyzed to evaluate the dynamics in the landslide’s topography and volumetric changes. The shaded relief single band was used to correlate the temporal images for the Nara and Nokot landslide using the COSI-Corr algorithm. The statistical and frequent correlator was used for landslide displacement. The result shows that the Nara landside has a surface movement ranging from 1 to 29 m in the NE scarp and lateral areas. The Nokot landslide has active NS, NE and NW scarps with a surface movement ranging from 1 to 25.5 m. The accuracy assessment reveals the RMSE calculated for the Nara landslide as 4.58 m and 4.24 m for the Nokot landslide. This study reflected the potential application of UAVs for monitoring the landslides dynamics to mitigate the hazard.

GIS technologies and consistency of the inventory system in the administration of objects of the ecological system

Аbstract. Problem. Nowadays, GIS-technologies allow you to store various data stores. The existing state cadastral administration systems in Ukraine need to be linked. Today, cadastre systems are distinguished – state land cadastre, natural resource cadastre, real estate cadastre, urban planning cadastre, environmental cadastre, mineral cadastre, water cadastre. Goal. All these administration systems have their own databases, but do not have a common administration system. So in the state cadastre of natural resources there are objects of the natural reserve fund, their area, approximate location is listed, but there is no information in the state land cadastre about the location of such objects, there are no geodetic coordinates, these objects are not displayed on the public cadastral map of Ukraine. We investigated the Kuplevatsky natural reserve fund in the Barvenkovsky district of the Kharkiv region, which has been listed as an NRF object since 1992, but there is no information about this object in the state cadastral administration system. Methodology. Our research, after geodetic survey of the territory and computer processing of the results, obtained a digital cartographic image of the NRF object in the Digitals software package. Results. Afterthat, we entered into the information layers of the administration of the state land cadastre information about the NRF object and linked it with the ecological cadastral system.

Multi-GNSS Single-Difference Baseline Processing at NGS with newly developed M-PAGES software

<p>The U.S. National Geodetic Survey (NGS) has historically processed dual-frequency GPS observations in a double-differenced mode using the legacy software called the Program for the Adjustment of GPS Ephemerides (PAGES). As part of NGS’ modernization efforts, a new software suite named M-PAGES (i.e., Multi-GNSS PAGES) is being developed to replace PAGES. M-PAGES consists of a suite of C++ and Python libraries, programs, and scripts built to process observations from all GNSS constellations. The M-PAGES team has developed a single-difference baseline processing strategy that is suitable for multi-GNSS. This approach avoids the difficulty of forming double-differences across systems or frequencies, which may inhibit integer ambiguity resolution. The M-PAGES suite is expected to deploy to NGS’ Online Positioning User Service (OPUS) later this year. Here, we present the processing strategy being implemented along with a performance evaluation from sample baseline solutions obtained from data collected within the NOAA CORS Network.</p>