An important element of orientation on the terrain by a topographic map is the determination of the point of its location. Various methods may be used for this. For local subjects, for the closest landmarks to the eye, measuring the distance traveled, notching for landmarks, backward notching for at least two landmarks.
Determination of the point of their location on the terrain by map, local objects, landmarks on the eye, distance measurement, notch by landmarks.
The easiest way is to determine your location using local objects. When you are next to any landmark depicted on the map (crossroads, a separate stone, a characteristic ledge of the forest, etc.). The location of the symbol on the map will indicate the desired point of our standing.
Determining your location using the closest reference points to the eye is the simplest and most basic way to approximate your location on a map. In this case, orient the map and identify one or two landmarks on it and on the ground. Then they determine by eye their location relative to these landmarks on the ground and put their location on a map.
For example, making a stop in an open area, you notice that in the direction of your movement you see a tree, and on the left at right angles – a rotary pillar of the communication line. Orienting the map, you found on it the image of a tree and the angle of rotation of the communication line. Then, having determined eyeballs that the tree is about 400 meters away from you, and the angle of rotation of the communication line is 200 meters away. We postpone these distances on the map so that there is an approximately right angle between them. You will find your location on the map..
Determination of the point of its location on the ground by measuring the distance traveled.
This method is used when driving on a road, trail, clearing or along any other line of the terrain indicated on the map (river bank, forest edge, communication line, etc.). And also when moving in a straight line in any particular direction. For example, to a remote landmark, and in conditions of poor visibility – in the direction of a given azimuth.
It is especially useful in conditions of poor visibility. In a closed or poor landmark area. Starting from any object recognized on the terrain and on the map (bridge, road intersection, forest edge, etc.), you take a couple of steps. In this case, the point of your location can always be determined by laying aside on the map scale the distance that you have traveled from the starting point in this direction of movement.
For example, having walked along a road 200 meters from the bridge in the direction of a trigonometric point, the tourist stopped. Putting aside the distance traveled from the bridge, he got a point of his location on a topographic map.
Determination of the point of its location in the area by serif according to landmarks.
This method is most suitable for open areas. Or in conditions of good visibility. When moving along the road or along some linguinear landmark, the notch of the point of its location is as follows.
We orient the map and identify on it a landmark visible on the ground from a given point. Then we put on the chart line or pencil to the image of this landmark. Without breaking the map orientation, we rotate it around the symbol. The intersection point of the line of sight along the ruler with the image of the road we are on will be the desired point of our location on the map.
The determination of the point of our location is simplified if the selected landmark is perpendicular to the direction of movement. Or in alignment with some other reference point. Also indicated on the map and visible from this point. Then the desired point of our location on the map is determined by the intersection of the road on which we are located, with a straight line drawn through a landmark perpendicular to the line of our movement.
In the second case – with a straight line passing through both landmarks forming the target. When drawing these lines, you do not even need to orient the map, nor to sight the landmarks using the ruler.
Determination of the point of its location in the area by reverse notch by at least two landmarks.
When driving off-road and directions not indicated on the map, the determination of one’s location is determined by a reverse notch based on at least two landmarks. To do this, find two local objects on the map in different directions on the terrain in an angle of at least 30 degrees from each other and no more than 150 degrees.
The topographic map is oriented at the compass, and then they are alternately endorsed for each landmark and drawn along the ruler with directions from the landmarks to themselves. The intersection on the map of these directions will be the point of our location.
Based on the book “Map and Compass My Friends”.