Matters of choosing the pixel size in topographic aerial photography

The existing regulatory documents on photogrammetric works are technologically outdated. They neither take into account the peculiarities of aerial photography with digital cameras, the navigation equipment used and modern image processing methods, nor regulate the technique of calculating the pixel size on the ground. In order to select the pixel size in the terrain for aerial photography with topographic requirements concerning to the results, the method of multivariate analysis of the input data is proposed. It is supposed to ensure the minimum pixel size on the ground according to such criteria as the accuracy of the aerial triangulation results, the accuracy of building a digital elevation model for orthotransformation, the possibility of the objects interpretation with a specified minimum size and consideration of camera exposure parameters. To determine the accuracy criteria, we used formulas for pre- calculation of spatial phototriangulation accuracy with multiple choice of parameters. Examples of pixel size selection in the terrain at designing aerial photography by an amateur camera for the purposes of large-scale mapping are considered. Conclusions on the necessity of solving the issues of selecting parameters of large scale aerial photography, taking into account multiple input data and used aerial survey equipment are made.

Mitigating Safety Concerns of SRU Stack Using Advanced Analytical/Optical Technologies

Objective/Scope (25-75 word) In SRU, Tail gas exhaust stacks are provided with external cladding, preventing condensation beneath refractory surfaces. External cladding is made of individual Aluminium sheet panels, each 1.7mx1.5mx3mm thk, weighing 60Kg, attached by screws / rivets. Stack size is 6.5mdia × 90m height. Due to high wind, panel sometimes detaches from stack, falling down from 90m height, posing serious HSE threat to plant personal safety. This paper details an analytical design approach, supported with high resolution, remote controlled drone inspection technic to resolve one such issue. Methods, Procedures, Process (75-100 word) Initially, detached and dropped screws were observed, due to wind loads & vibration, which lead to falling of a clad panel from 80m height, fortunately, when no personal was below. Detailed finite element analysis of external cladding was performed, considering wind loads and thermal loads on panels with stack to panel joint configuration. Periodic inspection of the joints is vital to confirm reliability of the joints, which is not possible during operation with conventional inspection methods in an SRU exhaust stack. Hence, a latest technology, high-resolution, optical camera assisted, drone, controlled & monitored by remote computers were employed to assess the panel integrity. Results, Observations & Conclusions (100-200 words) Analysis Results Finite element analysis was performed for the stack cladding. As this analysis was non-conventional, there is no well-established industry acceptance criteria for the analysis results. Hence, an acceptance criteria was jointly developed with Contractor, which is fundamentally the minimum number of screws per panel, required to be intact, during the 2 year period, to confirm the panel integrity. Distance Drone inspection Manned inspection was not feasible in a running plant. Also, conventional aerial survey drones could not be engaged, as it was unsafe to fly the drone above live plant. Hence, an aerial drone with high-resolution optical camera, with overlapping method was employed. Advanced post processing software was used to analyse the images for best results. Conclusion To ensure clad panels integrity and 100% personal safety, Based on Finite element analysis, the original screws have been replaced with rivets with the following acceptance criteria. The integrity of the cladding remains intact even if 20% of the screws / rivets are lost whether it is consecutive or random. Above 20% there may be impact and further investigation is advised. Panels were monitored three times periodically in 2 year span to assess the fasteners intactness. The images from the optical camera, after software processing confirmed the fasteners integrity. Novel/Additive Information (25-75 words) 100% Plant and personal safety is ADNOC's principal objective. Occasionally, achieving this target require unorthodox analysis and acceptance criteria development. Most of all, the conventional monitoring technics, due to their limitations, pushes us to explore alternate technologies. The new high-resolution, optical camera assisted, drone technic can be engaged in a running plant and the images are processed using proprietary software to achieve best results of minute details.

Design of Autonomous Unmanned System for Aerial Operations From Underwater Platforms

Surveillance and reconnaissance play a very important role in military and civil aspects. They are the key factors in military tactics and in the event of civilian calamities. In case of naval warfare, the submarines which are operating under deep water are required to carry out open land mass surveillance in an efficient manner without reaching to the water surface nor revealing their presence and position. This research paper proposes the conceptualized design to develop an autonomous unmanned octocopter system which is capable of being launched from an underwater platform such as submarines, with the help of a tethered launching mechanism known as octopod, to carry out surveillance, reconnaissance and payload delivery. In this paper, we present a novel method for development of UAV with special application on aerial survey from underwater platforms. A variety of design options which are investigated from various trade studies to evaluate the performance along with design configuration to satisfy the specific requirements are also presented in this paper.

Spatio-Temporal Patterns of Increasing Illegal Livestock Grazing over Three Decades at Moyowosi Kigosi Game Reserve, Tanzania

The global increase of livestock has caused illegal intrusion of livestock into protected areas. Until now, hotspot areas of illegal grazing have rarely been mapped, long-term monitoring data are missing, and little is known about the drivers of illegal grazing. We localized hotspots of illegal grazing and identified factors that influenced spatio-temporal patterns of illegal grazing over three decades in the Moyowosi Kigosi Game Reserve (MKGR), Tanzania. We used questionnaires with local pastoralists (N = 159), georeferenced aerial survey data and ranger reports from 1990–2019 to understand the reasons for illegal grazing in the area. We found that hotspots of illegal grazing occurred initially within 0–20 km of the boundary (H (3) = 137, p < 0.001; (H (3) = 32, p < 0.001) and encroached further into the protected area with time (H (3) = 11.3, p = 0.010); (H (2) = 59.0, p < 0.001). Further, livestock herd sizes decreased with increasing distance from the boundary (R = −0.20, p = 0.020; R = −0.40, p = 0.010). Most interviewees (81%) claimed that they face challenges of reduced foraging land in the wet season, caused by increasing land used for cultivation, which drives them into the MKGR to feed their livestock. We conclude that there is spatio-temporal consistency in the illegal livestock intrusion over three decades, and hotspot areas are located along the boundary of the MKGR. We suggest focusing patrols at these hotspot areas, especially during the wet season, to use limited law enforcement resources effectively.

A new technique for remote location of unknown caves and deep-seated faults by unmanned aerial systems (UAS)

Here, for the first time in Bulgaria, we demonstrate that aerial survey of the terrain with a coaxial thermal and visible camera mounted on an UAS can detect much larger number of entrances to underground cavities and deep seated faults than a detailed systematic ground survey by experienced personnel. Thus geophysical problems are solved with these remote sensing methods. It is extremely promising and reveals great opportunities for improving techniques for location of unknown caves and deep seated faults to a much higher level. Obtained results are a significant step forward in the state-of-the art.

An on-ice aerial survey of the Kane Basin polar bear (Ursus maritimus) subpopulation

There is an imminent need to collect information on distribution and abundance of polar bears (Ursus maritimus) to understand how they are affected by the ongoing decrease in Arctic sea ice. The Kane Basin (KB) subpopulation is a group of high-latitude polar bears that ranges between High Arctic Canada and NW Greenland around and north of the North Water polynya (NOW). We conducted a line transect distance sampling aerial survey of KB polar bears during 28 April–12 May 2014. A total of 4160 linear kilometers were flown in a helicopter over fast ice in the fjords and over offshore pack ice between 76° 50′ and 80° N′. Using a mark-recapture distance sampling protocol, the estimated abundance was 190 bears (95% lognormal CI: 87–411; CV 39%). This estimate is likely negatively biased to an unknown degree because the offshore sectors of the NOW with much open water were not surveyed because of logistical and safety reasons. Our study demonstrated that aerial surveys may be a feasible method for obtaining abundance estimates for small subpopulations of polar bears.

Alaska Beluga Whale Committee—a unique model of co-management

The Alaska Beluga Whale Committe (ABWC) was formed in 1988 to conserve beluga whales (Delphinapterus leucas) and manage beluga subsistence hunting in western and northern Alaska in cooperation with the National Marine Fisheries Service (NMFS). When the ABWC was formed, there was no consistently funded research or management programme for belugas in Alaska, and co-management was a new concept. The ABWC brought together representatives from beluga hunting communities; federal, state, tribal and local governments; and beluga researchers to develop and implement a programme to manage belugas. With funding from NMFS and others, the ABWC has collected data necessary for informed management decisions including the following: harvest data; aerial surveys of belugas in Bristol Bay and the eastern Bering and Chukchi seas; beluga tracking studies, including training hunters to attach transmitters; a pioneering genetics study of beluga stock identity that has facilitated collection of >2000 beluga skin samples; and a genetics-based mark–recapture study to estimate beluga abundance in Bristol Bay and validate aerial survey estimates. The ABWC is currently engaged in regional management planning in Kotzebue Sound and the eastern Bering Sea. It produces results that are scientifically valid, locally accepted and cost-effective and is an example of what can be achieved when Native hunters, scientists and managing agencies respect and listen to one another and work together. However, the current NMFS co-management funding process has fundamentally altered the relationship between NMFS and ABWC, with NMFS now acting more like a funding agency than a partner.

Structure, Faulting and Gas Accumulation: Southeast Wanganui Basin, New Zealand

<p>There has been low interest in petroleum exploration in the Wanganui Basin as it lacks known hydrocarbon source rock of sufficient age or burial depth. However, the onshore Southeast Wanganui Basin has many occurrences of methane-rich biogenic gas found in shallow water wells. This project used three studies across the Horowhenua area to examine the faulting style in the Southeast Wanganui Basin where it is bounded by the Tararua range- front, and how this faulting relates to the accumulation of gas deposits in the shallow sedimentary section. South of Levin the Tararua range front steps laterally near Muhunoa East Road. A previous seismic reflection line identified a deep intra-basement arrival, which could have been either a low-angle thrust fault or side-swipe from a pull-apart basin at the step in the Tararua range front. Two seismic lines and a gravity survey found no sub-vertical drops in basement depth which would indicate the presence of a pull-apart basin or a favourable surface off which a laterally travelling seismic wave could reflect. The intra-basement arrival on the previous seismic line was therefore interpreted to be from an intra-basement low-angle thrust fault. Also two biogenic gas sites also were surveyed. A shallow gas reservoir east of Levin on Wallace Road, abutting the Tararua range front, had been discovered when a water well was drilled; and a potential reservoir southwest of Sanson was located when an aerial survey identified a domed structure with high resistivity. In both areas biogenic gas was thought to be trapped in buried sand dunes at a depth of approximately 20 m. Shallow seismic refraction and reflection methods and amplitude variation with offset analysis were used to map both reservoir bodies and confirm the presence of biogenic gas.</p>

Structure, Faulting and Gas Accumulation: Southeast Wanganui Basin, New Zealand

<p>There has been low interest in petroleum exploration in the Wanganui Basin as it lacks known hydrocarbon source rock of sufficient age or burial depth. However, the onshore Southeast Wanganui Basin has many occurrences of methane-rich biogenic gas found in shallow water wells. This project used three studies across the Horowhenua area to examine the faulting style in the Southeast Wanganui Basin where it is bounded by the Tararua range- front, and how this faulting relates to the accumulation of gas deposits in the shallow sedimentary section. South of Levin the Tararua range front steps laterally near Muhunoa East Road. A previous seismic reflection line identified a deep intra-basement arrival, which could have been either a low-angle thrust fault or side-swipe from a pull-apart basin at the step in the Tararua range front. Two seismic lines and a gravity survey found no sub-vertical drops in basement depth which would indicate the presence of a pull-apart basin or a favourable surface off which a laterally travelling seismic wave could reflect. The intra-basement arrival on the previous seismic line was therefore interpreted to be from an intra-basement low-angle thrust fault. Also two biogenic gas sites also were surveyed. A shallow gas reservoir east of Levin on Wallace Road, abutting the Tararua range front, had been discovered when a water well was drilled; and a potential reservoir southwest of Sanson was located when an aerial survey identified a domed structure with high resistivity. In both areas biogenic gas was thought to be trapped in buried sand dunes at a depth of approximately 20 m. Shallow seismic refraction and reflection methods and amplitude variation with offset analysis were used to map both reservoir bodies and confirm the presence of biogenic gas.</p>