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Equations of motion
Published in Mohammad H. Sadraey, Aircraft Performance, 2017
A nautical mile or sea mile is a unit of distance and displacement. It is accepted for use with the SI unit, but it is not an SI unit. The nautical mile is used around the world for maritime and aviation purposes. It is commonly used in international law and treaties, especially regarding the limits of territorial waters. It developed from the geographical or statute mile. The nautical mile is roughly equal to 1 min* of angle at the equator. The angular length of the equator is 360° or roughly equivalent to 21,600 nautical miles. There is no official international standard symbol for the nautical mile. The symbols NM, “nm”, and “nmi” are commonly used in some areas (not to be confused with Nm, the official symbol for Newton meter). Here, we use the symbol “nm”.
Aircraft navigation
Published in Mike Tooley, David Wyatt, Aircraft Communications and Navigation Systems, 2017
The nautical mile (unlike the statute mile) is directly linked to the geometry of the earth. This quantity is defined by distance represented by one degree of arc of a great circle (assuming the earth to be a perfect sphere).
Identifying port congestion and evaluating its impact on maritime logistics
Published in Maritime Policy & Management, 2022
Xiwen Bai, Haiying Jia, Mingqi Xu
The primary data source is the radio-based vessel tracking system, Automatic Identification System (AIS). Attribute to the growing number of launches of commercial low-orbit satellites which are dedicated to capturing such AIS signals since 2010, the amount and quality of AIS data has been significantly improved. This novel data source has enhanced growing research opportunities aiming at harvesting the rich information content in the system. In a systemic literature review paper, Yang et al. (2019) identified the application of AIS data ranges from primary uses (e.g. navigation safety or illegal fishing tracking) to advanced application, such as, in emission monitoring. In this study, we utilize the AIS vessel tracking data to identify port areas as well as port congestion indicators by tracking vessel sailing and port call records. The dataset contains vessel movement information for the VLGCs during the period August 2016 to July 2020. The data fields include timestamp (by hour), coordinates (longitude and latitude vessel position at that timestamp), speed (nautical mile/hour), course over ground (COG) and draught (meters).
Improved prediction of oil drift pattern using ensemble of ocean currents
Published in Journal of Operational Oceanography, 2022
Prasad S.J, Balakrishnan Nair T.M, Balaji B
where u – zonal component of the wind/current mover; v – meridional component of the wind/current mover; Δt = t – t1 is the time elapsed between time-steps i; y is the latitude in radians; 111,120.00024 is the number of meters per degree of latitude (assumes 1’ latitude = 1 nautical mile everywhere); and Δx, Δy are the displacement in x, y directions respectively. At present movement in GNOME cannot occur between depth layers thus the vertical displacement, Δz, is held at zero.
The location of the Pink and White Terraces of Lake Rotomahana, New Zealand
Published in Journal of the Royal Society of New Zealand, 2019
The 1864 map has three map-reading aids not found on the 1861 map. It has a stated scale ratio of 1:12000 (meaning that one unit of length on the map is equal to 12,000 of the same units on the ground), and it has a scale bar for one quarter of a nautical mile. It also gives the latitude and longitude of Station 21 written on the map beside the station location point. It reads: 38° 18′ 30″S latitude, 176.27°E longitude.