Resection is a method of finding one's own location on a map by sighting two known landmarks. The procedure is as follows: Find at least two landmarks on the map that can be also identified on the ground.
What is resection in geography?
Resection is the method of locating one’s position on a map by determining the grid azimuth to at least two well-defined locations that can be pinpointed on the map. For greater accuracy, the desired method of resection would be to use three or more well-defined locations. When using the map and compass method–.
How do you use resection?
Resection is used when you DO NOT KNOW WHERE YOU ARE ON THE MAP. But you can see several prominent features and you know where those are on the map. You then use these prominent features to find out where you are on the map. (If you are confused which is which, just remember that when you are LOST and need to be RES cued, you do RES ection.)
How do you use a map and compass to perform resection?
When using a map and compass to perform resection, it is important to allow for the difference between the magnetic bearings observed and grid north (or true north) bearings ( magnetic declination) of the map or chart.
What is the difference between intersection and resection?
Intersection is used when YOU KNOW WHERE YOU ARE ON THE MAP but you need to find out where the objective (that you are looking at) is on the map. Resection is used when you DO NOT KNOW WHERE YOU ARE ON THE MAP.
What is resection on a military map?
Resection is the method of locating one's position on a map by determining the grid azimuth to at least two well-defined locations that can be pinpointed on the map. For greater accuracy, the desired method of resection would be to use three or more well-defined locations.
How do you Nav a resection land?
1:473:40Land Navigation: Intersection and Resection - YouTubeYouTubeStart of suggested clipEnd of suggested clipStart by getting the magnetic azimuth to the first object and converting that to a grid asmath. ThenMoreStart by getting the magnetic azimuth to the first object and converting that to a grid asmath. Then convert that to a back Asthma.
What is modified resection on a map?
Modified resection is the method of locating one's position on the map when the person is located on a linear feature on the ground, such as a road, canal, or stream.
What is the difference between resection and intersection?
In resection, the one point with unknown coordinates is occupied and sightings are taken to the known points; in intersection, the two points with known coordinates are occupied and sightings are taken to the unknown point.
What is a resection in surveying?
In surveying, free stationing (also known as resection) is a method of determining a location of one unknown point in relation to known points. There is a zero point of reference called a total station. The instrument can be freely positioned so that all survey points are at a suitable sight from the instrument.
How do you calculate resection?
0:0637:38RESECTION | CALCULATING THE COORDINATES OF AN UNKNOWN ...YouTubeStart of suggested clipEnd of suggested clipSo let's start. The aim of resection is to determine the coordinates of an unknown point x by takingMoreSo let's start. The aim of resection is to determine the coordinates of an unknown point x by taking total station measurements to the control stations a and b for example from the unknown point x.
How do you calculate modified resection?
Modified Resection Method:Orient the map using a compass and/or by terrain association.Locate a point in the distance that can be easily identified on the ground and on the map.Determine the magnetic azimuth from your location to the distant known point.Convert the magnetic azimuth to a grid azimuth.More items...
What is 3 point resection surveying?
The three-point resection method (also known as the “three-point problem”) is used to compute the coordinates of an unknown point by occupying the resected point and measuring angles and distance toward three known points, since the angles between three known points are determined at the unknown point (ElHassan, 1986).
How do you do a two point resection?
0:001:45Resection by Two Point Problem || civil || Blub || - YouTubeYouTubeStart of suggested clipEnd of suggested clipLet a and b are two points for which plotted positions of which are known and let c be the point toMoreLet a and b are two points for which plotted positions of which are known and let c be the point to be plotted. Choose an auxiliary point d near c to assist the orientation.
What is resection in surveying?
Resection and its related method, intersection, are used in surveying as well as in general land navigation (including inshore marine navigation using shore-based landmarks). Both methods involve taking azimuths or bearings to two or more objects, then drawing lines of position along those recorded bearings or azimuths.
How does resection work?
Resection simply reverses the intersection process by using crossed back bearings, where the navigator's position is the unknown. Two or more bearings to mapped, known points are taken; their resultant lines of position drawn from those points to where they intersect will reveal the navigator's location.
What is the reverse of the intersection method?
The reverse of the intersection technique is appropriately termed resection.
How many points do you need to resection?
For the purposes of doing it correctly you’ll need at least two known points but obviously, three or more is ideal. There are three methods of using resection, using the map and compass method, the straightedge method and the modified method. In a perfect world, the map and compass method is the way to go.
Which method is the least accurate?
Modified Resection Method: The modified method is the least preferred and the least accurate method but is useful in certain situations. If you’re not certain of your exact location but are located on a linear terrain feature such as a road, creek or along a similar body of water, this can pinpoint your position.
Resection Versus Intersection
Fixing A Position
- When resecting or fixing a position, the geometric strength (angular disparity) of the mapped points affects the precision and accuracy of the outcome. Accuracy increases as the angle between the two position lines approaches 90 degrees. Magnetic bearings are observed on the ground from the point under location to two or more features shown on a ma...
References
- Mooers Jr., Robert L., Finding Your Way In The Outdoors, Outdoor Life Press (1972), ISBN 0943822416
- Kals, W.S., Practical Navigation, New York: Doubleday & Co. (1972), ISBN 0385002467
- Seidman, David, and Cleveland, Paul, The Essential Wilderness Navigator, Ragged Mountain Press (2001), ISBN 0071361103
See Also
External Links