magnetic north
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2021 ◽  
Vol 16 (1) ◽  
pp. 37-51
Author(s):  
Piotr Banasik

This work concerns the assessment of the cartometricity of the 19th century plan of the village of Lobzow near Krakow in Poland, known as “Mapa Łob­zowa z przyległościami”. The plan has not been researched in this respect so far. The aim of this study was to establish its scale and orientation in relation to directions of the world. A high resolution raster of the plan provided by the Historical Museum of the City of Krakow was used for the study. At first, an attempt was made to clarify the date of the plan’s origin. An analysis of infor­mation contained in archival documents shows that the plan of Lobzow was most probably created between 1824 and 1852, which corresponds with the period when the large­scale cadastral map was developed in Galicia. Therefore, selected sections of this map, from the area covered by the plan, were used for research. The scale value of the Lobzow plan was calculated using the lengths of sections between selected points on the plan and map. The calculated plan scale is close to the scale of the detailed map section detailed sheet of the ca­dastral map. It was established that the plan of Lobzow has the orientation relative to magnetic north as was common in the first half of the 19th century. The mutual dependencies between the orientation of the plan and the cadastral map in relation to the direction of true geographical north were illustrated. The final result of the work was to show the changes in the topography of Lobzow that have taken place over nearly 200 years.


Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7384
Author(s):  
Charlotte Brandebusemeyer ◽  
Anna Ricarda Luther ◽  
Sabine U. König ◽  
Peter König ◽  
Silke M. Kärcher

Spatial orientation and navigation depend primarily on vision. Blind people lack this critical source of information. To facilitate wayfinding and to increase the feeling of safety for these people, the “feelSpace belt” was developed. The belt signals magnetic north as a fixed reference frame via vibrotactile stimulation. This study investigates the effect of the belt on typical orientation and navigation tasks and evaluates the emotional impact. Eleven blind subjects wore the belt daily for seven weeks. Before, during and after the study period, they filled in questionnaires to document their experiences. A small sub-group of the subjects took part in behavioural experiments before and after four weeks of training, i.e., a straight-line walking task to evaluate the belt’s effect on keeping a straight heading, an angular rotation task to examine effects on egocentric orientation, and a triangle completion navigation task to test the ability to take shortcuts. The belt reduced subjective discomfort and increased confidence during navigation. Additionally, the participants felt safer wearing the belt in various outdoor situations. Furthermore, the behavioural tasks point towards an intuitive comprehension of the belt. Altogether, the blind participants benefited from the vibrotactile belt as an assistive technology in challenging everyday situations.


Aerospace ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 263
Author(s):  
Lorenzo Frezza ◽  
Paolo Marzioli ◽  
Fabio Santoni ◽  
Fabrizio Piergentili

The usage of aeronautical radio-frequency navigational aids can support the future stratospheric aviation as back-up positioning systems. Although GNSS has been extensively redundant in the last years of space operations, radio NavAids can still be supportive of navigation and tracking for novel mission profiles. As an example, in 2016, VHF Omnidirectional Range (VOR) has been proven to work well above its standard service volume limit on a stratospheric balloon flight with the STRATONAV experiment. While VOR provides the “radial” measurement, i.e., the angle between the Magnetic North and the line between the receiver and the transmitting ground station, the intersection of two or more radials at a time allows to perform ground track reconstruction for the vehicle to be tracked. This paper reports the results from the data re-processing from STRATONAV: the acquired radials have been intersected in order to achieve positioning. The radials interfacing method, the position calculation methodology, and the data acquisition strategies from STRATONAV are reported together with the data analysis results.


2021 ◽  
Author(s):  
Frédéric Guattari ◽  
Pierrick Auregan ◽  
Elliot de Toldi ◽  
Theo Laudat ◽  
Laurent Mattio

<p><span><span>To install a seismometer with a properly defined orientation - inside a vault or into a borehole - as a single station including various instruments or as a part of an array - an ‘adequate’ tool and an ‘absolute’ reference are needed.</span></span></p><p><span><span>In the past, and sometimes it persists nowadays, magnetic North have been used as a reference for Z-orientation of seismic station. Several studies have extensively measured the orientation error that have been made with this method, using an optical gyrocompass providing True-North as a reference, and their work will be summarized here.</span></span></p><p><span><span>In these studies, optical Gyrocompass is said to be the good solution, even if it is too heavy, expensive, and difficult to export. This paper will explain how iXblue has overcome these limitations to design the new-born Seistans Optical Gyrocompass.</span></span></p><p><span><span>Moreover, to aim True-North with a reliable accuracy is not the only think you need to do on the field. The method to transfer the North-line from the gyrocompass to the instrument to aligned must not induce errors that ruined the accuracy obtained using state-of-the-art gyrocompass. So an exhaustive study of the different ways to transfer the orientation from the compass to the aligned sensor will be presented, and corresponding added uncertainty will be evaluated, which is a good way to promote good practice on the field.</span></span></p><p><span><span>Finally, some figures will be gathered and shared from literature to quantify the precision needed for the alignment of a seismic sensor. There are today so few papers about this important matter that it is worth to spread their information.</span></span></p>


Author(s):  
Asmuni Asmuni ◽  
Hasan Matsum ◽  
Imamul Muttaqin

True North true north is any point on the earth to the North pole, this is because the North and South poles point precisely to the earth's axis of rotation. Therefore true north is North based on the earth's axis not North based on the earth's magnetism. So the difference is true North shows the true north direction of the earth while magnetic North is the North direction of the magnetic compass needle. Magnetic north does not coincide with Earth's true north. To find out the true North of the earth using a compass, you need to know the magnetic declination first. To know the magnetic declination can be done through a magnetic declination calculator such as WMM (world magnetic model) which can be downloaded through the crowdmag application playstore. In determining the direction of the Qibla it is required to determine the True North point of the earth.


2020 ◽  
Vol 34 (1) ◽  
pp. 13-35
Author(s):  
Mark J. Carlotto

There are hundreds, perhaps thousands of sites of archaeological importance throughout the world. In this study the alignments of over twohundred ancient sites were measured and analyzed. Sites are organized into eight geographic regions: South America, Mesoamerica, North America, Europe, the Middle East, Africa, Asia and the Pacific Ocean. Google Earth imagery and measurement tools were used to estimate the alignment of linear and rectilinear structures at these sites with respect to true (geographic) north. In considering standard celestial and geographic reasons for the alignments, many were found to be oriented to the cardinal directions, in the directions of solstices and other solar events, to lunar standstills, and certain stars. A number of sites in China and Thailand were likely aligned to magnetic north at the time of construction using a compass. Some sites appear to have been aligned to “sacred directions” that include Islamic qibla and Quechua ceques. Site alignment statistics reveal similarities and differences between geographical regions in terms of how sites within regions are aligned. Perhaps the most unexpected finding is that the alignment of about half of the sites could not be explained in terms of any of the reasons considered.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Alessandro Cresci ◽  
Caroline M. Durif ◽  
Claire B. Paris ◽  
Steven D. Shema ◽  
Anne Berit Skiftesvik ◽  
...  

Abstract The European eel (Anguilla anguilla) hatches in the Sargasso Sea and migrates to European and North African freshwater. As glass eels, they reach estuaries where they become pigmented. Glass eels use a tidal phase-dependent magnetic compass for orientation, but whether their magnetic direction is innate or imprinted during migration is unknown. We tested the hypothesis that glass eels imprint their tidal-dependent magnetic compass direction at the estuaries where they recruit. We collected 222 glass eels from estuaries flowing in different cardinal directions in Austevoll, Norway. We observed the orientation of the glass eels in a magnetic laboratory where the magnetic North was rotated. Glass eels oriented towards the magnetic direction of the prevailing tidal current occurring at their recruitment estuary. Glass eels use their magnetic compass to memorize the magnetic direction of tidal flows. This mechanism could help them to maintain their position in an estuary and to migrate upstream.


2019 ◽  
Vol 19 (2) ◽  
pp. 195-201
Author(s):  
Chris M. Hall ◽  
Magnar G. Johnsen

AbstractA hypothesis is proposed wherein changes in the Earth's magnetic field affect the migratory paths of snow buntings (Plectrophenax nivalis), and in particular from wintering grounds in the Russian/Ukrainian steppes to breeding grounds on Svalbard and with a typical stopover in Finnmark in northern Norway. If one were to assume ignorance of the secular movement of the magnetic north pole approximately 1500 km northwards between 1908 and 2020, the magnetoreceptor contribution to snow buntings' navigation would result in winter-to-summer migratory paths progressively further to the East. In turn, this could be a contributing factor to declining populations in Finnmark and favouring a more frequent flightpath over the Kola Peninsula. On the other hand, short-term perturbations in the magnetic field (i.e. induced by solar activity) and therefore existing for a relatively small proportion of the flight time (if at all) for the individual migrations legs seem unlikely to influence the stopover locations significantly. Even so, these space-weather induced variations cannot be disregarded, particularly for success in reaching Svalbard.


2019 ◽  
Vol 8 (6) ◽  
pp. 280 ◽  
Author(s):  
Brodeur ◽  
Coetzee ◽  
Danko ◽  
Garcia ◽  
Hjelmager

Geographic information metadata provides a detailed description of geographic information resources. Well before digital data emerged, metadata were shown in the margins of paper maps to inform the reader of the name of the map, the scale, the orientation of the magnetic North, the projection used, the coordinate systems, the legend, and so on. Metadata were used to communicate practical information for the proper use of maps. When geographic information entered the digital era with geographic information systems, metadata was also collected digitally to describe datasets and the dataset collections for various purposes. Initially, metadata were collected and saved in digital files by data producers for their own specific needs. The sharing of geographic datasets that required producers to provide metadata with the dataset to guide proper use of the dataset—map scale, data sources, extent, datum, coordinate reference system, etc. Because of issues with sharing and no common understanding of metadata requirements, the need for metadata standardization was recognized by the geographic information community worldwide. The ISO technical committee 211 was created in 1994 with the scope of standardization in the field of digital geographic information to support interoperability. In the early years of the committee, standardization of metadata was initiated for different purposes, which culminated in the ISO 19115:2003 standard. Now, there are many ISO Geographic information standards that covers the various aspect of geographic information metadata. This paper traces an illustration of the development and evolution of the requirements and international standardization activities of geographic information metadata standards, profiles and resources, and how these attest to facilitating the discovery, evaluation, and appropriate use of geographic information in various contexts.


2018 ◽  
Vol 60 (3-4) ◽  
pp. 605-609
Author(s):  
Allan P. Reid
Keyword(s):  

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