Glossary
- Line Of Position (LOP): the locus of points along which a ship's position must lie. ...
- Leading lights or range lights are a pair of light beacons, forming a leading line, indicating a safe passage for vessels entering a shallow or dangerous channel; and may also ...
- Transit bearing / range: the method of lining up charted objects to obtain an LOP.
What is a line of position on a navigation chart?
What is a line of position in navigation? What is a line of position in navigation? Position Lines. A position line or Line of Position – LOP is a line that is plotted on the chart on which the boat position lies. It might also be a circle so it could then be called a position circle.
What is a line of position?
A Line of Position contains all the possible positions of an observer on Earth when viewing a celestial body at a given angle. Pay attention to the values needed for plotting since we will examine how to obtain these in the remainder of the course. If playback doesn't begin shortly, try restarting your device.
What is a leading line on a boat?
less distance between the vessel and the closest aid to navigation. One of these four ranges consists of two lights that are intentionally placed to provide an LOP. These pairs of lights are called leading lights producing a leading line: the recommended track. In depth: ranges and leading lines ranges and leading lines .
What is line of position (LOP)?
yacht charters with instruction in Greece . Line Of Position (LOP): the locus of points along which a ship's position must lie. A minimum of two LOPs are necessary to establish a fix.
How do you find line of position in navigation?
A position line or Line of Position – LOP is a line that is plotted on the chart on which the boat position lies. It might also be a circle so it could then be called a position circle. It is used to confirm your position on the chart. You need two or three lines intersecting to get a confirmed fix.
How do you draw a line of position?
5:168:01Plotting an LOP - YouTubeYouTubeStart of suggested clipEnd of suggested clipBody. The line of position lies perpendicular to the azmuth at the altitude intercept use a ruler toMoreBody. The line of position lies perpendicular to the azmuth at the altitude intercept use a ruler to draw your line of position.
Lines of position
The modern chart shows us positions of many recognizable aids to navigation aids to navigation like churches and lighthouses, which facilitate the approach to a coastal area. This concept originated from a chart by Waghenaer and proved a milestone in the development of European cartography.
Ranges
A precise way to obtain a LOP – and without a compass – is to locate two aids to navigation in line. The map of Wildrooz island aboveon the right shows four examples of ranges, each consisting of two aids to navigation:
Position fix
If two LOPs intersect we can construct a position fix → the ship's position on the earth. Often, however, a triangle occurs when a third LOP is added in the construction. This indicates that there are errors involved in at least one of the bearings taken.
Estimated position
It is sometimes impossible to obtain more than one LOP at a time. To determine the ship's position with one aid to navigation we can use a “ running fix ”, see below when a second LOP becomes available afterwards. In the meantime we aim to plot an estimated position .
Dead reckoning
Dead reckoning is a technique to determine a ship's approximate position by applying to the last established charted position a vector or series of vectors representing true courses and speed through the water.
Running fix
Under certain circumstances – such as low visibility – only one line of position can be obtained at a time. In this event, a line of position obtained at an earlier time may be advanced to the time of the later LOP. These two LOPs should not be parallel to each other; remember that the optimal angular spread is 90°.
Danger bearing
Like dead reckoning, the danger bearing is an important tool to keep the ship out of harm's way.
What is the line of position?
in navigation and geodesy, a line at all points of which a quantity measured by observations to determine the position of the observer on the earth’s surface has the same magnitude as at the observation point.
What is the line of sight?
Two or more LOPs are required to establish a fix. line of sight. i. The straight line between two points. This line is in the plane of the great circle but does not follow the contour of the earth. Radar and some forms of radio waves are capable of being received in the line of sight. ii.
What is the meaning of the line at all of whose points some quantity, measured to determine the observer’s
in navigation and geodesy , a line at all of whose points some quantity, measured to determine the observer’s position on the earth’s surface, has the same value as at the point of observation. Such quantities may be
What is the intersection of two or more lines of position drawn on a map?
The intersection of two or more lines of position drawn on a map makes it possible to determine the location of the observer. Line of Position. in navigation and geodesy, a line at all of whose points some quantity, measured to determine the observer’s position on the earth’s surface, has the same value as at the point of observation.
Who invented the line of position method?
Since the late 19th century, celestial lines of position have been calculated and constructed by an even more convenient method proposed by the French sailor M. St.-Hilaire in 1875. A generalization of the line-of-position method was made by the Soviet scientist V. V. Kavraiskii.
Who discovered the celestial lines?
This method was first published by the American sailor T. Sumner in 1843. Such celestial lines of position are called Sumner lines. A convenient, simple method of calculating and constructing these curved lines on a map was demonstrated in 1849 by the Russian sailor M. A. Akimov.
Lines of position
The modern chart shows us positions of many recognizable aids to navigation aids to navigation like churches and lighthouses, which facilitate the approach to a coastal area. This concept originated from a chart by Waghenaer and proved a milestone in the development of European cartography.
Ranges
A precise way to obtain a LOP – and without a compass – is to locate two aids to navigation in line. The map of Wildrooz island aboveon the right shows four examples of ranges, each consisting of two aids to navigation:
Position fix
If two LOPs intersect we can construct a position fix → the ship's position on the earth. Often, however, a triangle occurs when a third LOP is added in the construction. This indicates that there are errors involved in at least one of the bearings taken.
Estimated position
It is sometimes impossible to obtain more than one LOP at a time. To determine the ship's position with one aid to navigation we can use a “ running fix ”, see below when a second LOP becomes available afterwards. In the meantime we aim to plot an estimated position .
Dead reckoning
Dead reckoning is a technique to determine a ship's approximate position by applying to the last established charted position a vector or series of vectors representing true courses and speed through the water.
Running fix
Under certain circumstances – such as low visibility – only one line of position can be obtained at a time. In this event, a line of position obtained at an earlier time may be advanced to the time of the later LOP. These two LOPs should not be parallel to each other; remember that the optimal angular spread is 90°.
Danger bearing
Like dead reckoning, the danger bearing is an important tool to keep the ship out of harm's way.
