The determination of the standing point on the map is carried out eyeballing according to the nearest landmarks, measuring distances, measured distance and direction, and backsection. When choosing a method, the nature of the terrain, visibility conditions, the presence of time, as well as the accuracy with which it is desirable to determine the standing point, are taken into account.
The determination on the map of the standing point on the ground is eye-catching according to landmarks, measuring distances, measured distance and direction, reverse notch.
It is recommended to determine the standing point by eyeballs according to the closest landmarks in a medium-rough terrain, when the point is close to the terrain object shown on the map. To do this, orient the map. Two or three closest landmarks are recognized on it and the distance to them is eye-measured. At certain distances to landmarks, taking into account the directions, a standing point on the map.
The accuracy of determining the standing point on the map in this way depends mainly on the distances to landmarks. The larger these distances, the less reliably the standing point is determined. When located from landmarks at a distance of up to 500 meters, a standing point with sufficient experience is determined with an average error of the order of 20% of the average distance to landmarks.
Definition on a map of a point of standing on the ground by measuring distances.
The method is mainly used when driving on a road or along a linear contour. Mostly in closed areas or in poor visibility conditions. The essence of the method: measure the distance (speedometer, steps) from a landmark located near the road or some other linear landmark, to a defined point of standing. Then this distance is laid on the map along the road (linear landmark) in the corresponding direction. The accuracy of determining the standing point in this way depends mainly on the magnitude of the error in measuring distance on the ground.
Definition on a map of a point of standing on the ground in direction and distance.
The method is used when only one landmark is recognized. In this case, the map is oriented according to the magnetic declination. Then, a ruler is applied to the landmark on the map, they are directed by sight to the same landmark on the ground and a line is drawn. You can also see through a pencil mounted vertically. To do this, the oriented map should be in a horizontal position at approximately the level of the chin.
A pencil is placed perpendicularly on the image of a landmark on a map, it is endorsed through it on a landmark and, without changing the position of the eye and the map, slowly move the pencil over itself. On the plotted line of sight from the image of the landmark mark the distance, which is pre-measured in steps, binoculars, range finder or assessed eye.
Methods of sighting when determining on the map the standing points on the terrain in direction and distance.
Under these conditions, the standing point can be determined by another method. At a standing point, measure the magnetic azimuth to a landmark with a compass. Then this azimuth is translated in the opposite direction (180 degrees are added or subtracted), and the latter is a directional angle, along which a direction is drawn from a landmark on the map. In this direction and lay the measured distance. The resulting point will be the desired standing point.
An example of determining on a map a point of standing on the ground in direction and distance.
Given a magnetic azimuth to a landmark (geodetic point) of 30 degrees, a distance of 1,500 meters, the correction to the magnetic azimuth upon transition to a directional angle of +12 degrees. Define a standing point.
The reverse azimuth is 210 degrees (30 + 180), the directional angle is 222 degrees (210 + 12). The necessary constructions are shown in the diagram above. The average error in determining the standing point by distance and direction is about 5% of the distance from the standing point to the landmark. When measuring distance in steps, and azimuth with a compass.
Determination on a map of a point of standing on the ground by reverse notch in one direction.
This method is used while on the road (or other linear object), with which only one landmark is visible, located away from it. The map is possibly more accurately oriented and sighted on a landmark. The intersection point of the line of sight and the road will be the desired point of standing.
The standing point under the same conditions can be determined by the following technique. Measure the magnetic azimuth to the landmark, translate it into the opposite. And the latter is converted into a directional angle. According to the value of the directional angle, a direction is drawn from a reference point to the intersection with the road.
The average error in determining the standing point by this method with careful implementation of the techniques is about 10% of the range at a notch angle of 30 to 60 degrees and from 120 to 150 degrees. And about 5% at a notch angle of 60 to 120 degrees.
Determination on the map of the standing point on the ground by reverse notch in three (two) directions.
This method is mainly used in an open area, poor in landmarks, when three (in extreme cases, two) landmarks are recognized. If possible, you should use landmarks closer to the standing point so that the directions from the landmarks at the standing point intersect at angles between 30-150 degrees.
The map is carefully orientated by the compass, a ruler is applied to the symbol of one of the landmarks on the map and directed to the same landmark on the ground. Then draw a line on yourself. Without disrupting the orientation of the map, in the same way they draw directions to the second and third landmarks. The intersection of the three directions usually forms a triangle, the center of which will be the point of standing.
Scheme for determining the standing point by reverse notch.
In two directions, the standing point is determined less accurately, and most importantly, without control. Under the same conditions when it is difficult to work with the map (it is raining, etc.), the standing point can be determined by magnetic azimuths measured from the standing point to landmarks. Magnetic azimuths are reversed, and the latter in directional angles. And already on them the directions on the map are drawn from the corresponding landmarks. The average error in determining the standing point by a reverse notch in three landmarks is about 15% of the average distance to landmarks.
Determination on the map of the standing point on the ground using the Bolotov method.
Bolotov’s method for determining the standing point is used in open areas where there are few landmarks, but they are visible from afar. And mainly when you cannot orient the map by compass or measure magnetic azimuths, for example, while in a car.
A sheet of transparent paper is placed on a rigid base (cardboard, plywood, etc.). They mark a point around the center, draw a ruler from this point on the landmarks and draw lines. Then the transparent paper is placed on the card and by moving it find a position in which all the lines pass through the corresponding landmarks on the card. In this position, the transparent paper transfers (splices) a point onto the card. This point will be a standing point..
The average error in determining the standing point by the Bolotov method, provided that the directions intersect at angles within 30-150 degrees, will be about 15% of the average distance to the landmark. In the presence of a goniometer device, counts are made for the selected landmarks, radial directions are built from their values using the artillery circle, and, like Bolotov’s method, they find a standing point.
Based on materials from the Handbook of Military Topography.
A. M. Govorukhin, A. M. Kuprin, A. N. Kovalenko, M. V. Gamezo.