Basic contour distance, how to calculate contour distance

The ground inclination angle is six degrees, and the basic contour distance of the topographic map at a scale of 1:2000 is 2 meters.

The height difference between adjacent contour lines on a topographic map is called contour distance, also known as contour line spacing (separation), which is represented by h. On the same topographic map, the contour lines are the same contour distance. The smaller the interval between contour contours, the more detailed the changes in the ground can be.

The larger the contour distance, the more sketchy the representation of the ground on the map; However, when the contour distance is too small, the contour lines on the topographic map are too dense, which will affect the clarity of the map, and the surveying and mapping workload will increase and take longer.

When surveying and mapping topographic maps, the appropriate contour distance should be selected according to the actual situation, according to the size of the mapping scale and the steepness of the terrain of the survey area, and the contour distance is called the basic contour distance.

Features: large-scale maps, small degree of reduction, detailed representation of the landform, contour distance can be small; On a small-scale map, the terrain is roughly represented and the contour distance must be increased. On the other hand, although the scale of the map is the same, the size of the contour distance can vary depending on the content of the map and the undulations of the terrain.

The basic contour spacing is proportional. 1:2000 is a 2-meter line and a 10-meter thick line.

1:5000 is a 5-meter strip. 1：

10,000 is ten meters a piece. The ground is 6 degrees, and the actual plane distance is meters. =2/tg6

The plane distance on the graph of 1:2000 is. =

Contour distance Inside contour height Outside contour height. The height difference between adjacent contour lines on a topographic map is called contour distance, also called contour line spacing, and the crack foci are represented by h. On the same topographic map, the contour lines are the same contour distance. The smaller the interval between contour contour lines.

Characteristics of contour lines:

1. At the same contour line, the elevation of each point of the old silver of the source banquet is equal.

2. The contour line should be a closed curve.

3. Contour lines generally cannot intersect or overlap. Contour lines at cliffs and cliffs intersect or overlap, and the intersection points appear in pairs when they intersect.

4. The contour line is orthogonal to the ridge and valley (geologic line).

5. Between adjacent contour lines, the ground slope i is proportional to the contour distance h, and inversely proportional to the horizontal distance d, that is, in the same picture, h is a fixed value, and the denser the contour line, that is, the smaller d is, the steeper the ground slope; Conversely, the slope is slower. Contour lines are evenly distributed, indicating that the ground slope is uniform and consistent.

Contour horizontal distance is the distance between two contour lines in the horizontal direction.

Contour distance is the distance between two adjacent contour lines in the vertical direction.

In general, the contour distance on a topographic map is fixed, so the greater the contour line distance, the more gentle the terrain is, and vice versa, the steeper the terrain.

The curve formed by connecting the points of equal height is called a contour line.

The difference in elevation between two adjacent contour lines is the contour distance.

Contour distance is the distance between two contour lines (the contour distance on a contour topographic map is equal), and contour lines are lines that connect points of equal elevation on the map.

The median high lines in the figure are 210 meters, 190 meters, 170 meters, and 150 meters, and the difference between the two adjacent contour lines is 20 meters, and the contour distance is 20 meters.

Contour distance refers to the difference in elevation between two adjacent contour lines on the topographic map (also called relative height: it must be judged to be on the same contour line). The size of the contour distance depends on the size of the map scale.

Method 1: Subtract the values of two adjacent contour lines.

Method 2: If you can't directly judge the data of two adjacent contour lines, find two marked values in the figure, count how many contour lines there are between these two values, and divide the difference between these two values by the number of contour lines between them plus 1. For example:

If there are two contours marked with 50 and 100 respectively, and there are 4 contours between them, then (100-50) (4+1)=10, then the equivalence is 10

You see, there are two intervals between 170 and 130, and then 170-130 = 40, and 40 divided by 2 equals 20!

In the contour topographic map, according to the different bending forms of the contour lines, you can see the general condition of the surface morphology From the contour topographic posture map, it can be seen that the height difference between the two contour lines in the map is 50 meters, that is, the middle distance in the map is 50 meters

Therefore, c