What are the characteristics of contour lines? What are the contour properties

Summit: Contour line closed and decreasing from center to periphery, basin or depression: contour line closed and gradually increasing from center to periphery.

If there is no numerical annotation, it can be judged according to the slope line: (slope line - ** perpendicular to the contour line.)

Ridge: The contour protrusion points to a lower elevation. The contour line protrudes from high to low, which is the ridge.

Valley: The contour protrusion points to higher elevations. The contour line protrudes from low to high, which is the valley.

Saddle: The empty part between two ridges or valley contours facing each other. The shape is similar to that of a saddle.

Gentle slopes and steep slopes and steep cliffs: Cliffs are at the intersection of contour lines. The denser the contour line, the steeper the terrain; The sparser the contour line, the more gentle the slope.

1) Ground points located on the same contour line at the same altitude.

2) Contour lines of different elevations cannot intersect in the same image, except for cliffs. The height difference of adjacent contour lines in the contour is generally the same, so the ground slope is inversely proportional to the horizontal distance between the contour lines, and the smaller the horizontal distance of the adjacent contour lines, the denser the contour line arrangement, the greater the ground slope. The greater the horizontal distance between adjacent contour lines, the sparser the contour line arrangement, the smaller the ground slope. Therefore, the contour line can reflect the undulating situation of the surface and the characteristics of the surface structure.

Contour. The characteristics are:

1.The elevations of points on the same contour line are equal;

2.The contour line is a closed curve, if it is not closed in this view sheet, it must be closed outside the view;

3.Except at cliffs or cliffs, contour lines cannot intersect or coincide on the diagram;

4.The horizontal distance of the contour line is small, indicating that the slope is steep, and the horizontal distance is large, indicating that the slope is gentle;

5.The contour line is orthogonal to the ridge line and the valley line.

Here are the specific features:1. Including on the same contour line, the height of any point is equal;

2. The height difference between adjacent high lines is also the same;

3. The horizontal spacing of the contour line can indicate the steepness or gentleness of the terrain;

4. Contour lines are closed or continuous curves, and contour lines generally do not overlap or intersect.

A contour line is a closed curve of adjacent points of equal elevation on a topographic map. Contour lines are obtained by connecting closed curves of points at the same altitude on the ground, projecting them vertically onto a horizontal plane, and miniaturizing them on the drawing in proportion. Contour lines can also be seen as the intersection of horizontal planes at different altitudes with the actual ground, so contour lines are closed curves.

The numbers marked on the contour line are the elevation of the contour line.

1. The altitude of the ground points located on the same contour line is the same. However, points with the same altitude are not necessarily located on the same contour line.

2. In the same pictureContours of different elevations cannot intersect except for cliffs.

3. The height difference of adjacent contour lines in the contour is generally the sameTherefore, the ground slope is inversely proportional to the contour line distance between the contour lines, and the smaller the contour line level, the denser the contour line arrangement, the greater the ground slope. On the contrary, the larger the contour line distance and the sparser the contour line arrangement, the smaller the ground slope.

4. A contour line is a closed curveIf it cannot be closed in the same frame, it will be closed in an adjacent or other frame.

5. Contour lines change direction when passing through ridges or valleysTherefore, the ridgeline or valley line is a tangent line that will be perpendicular to the turning point of the contour line, that is, the contour line is orthogonal to the ridgeline or valley line.

** of contour lines.

The use of contour lines to show the landform is inspired by the bathymetrics. In 1728, the Dutch engineer Krucchi first used the bathymetry method to represent the depth of the river and the condition of the riverbed, and later applied it to represent the depth of the sea.

In 1729, Kurghs made the first bathymetric charts, which were later applied to land to represent the undulating forms of the landscape. In 1791, the first topographic map of contours was drawn up by Tubuntril, France, and Cuppin-Trillim used contour lines to represent the landforms of the French domain.

In the late 18th and early 19th centuries, contour lines gradually began to be used in topographic maps. In the second half of the 19th century, the contour line method broke through the barriers of difficult identification and became recognized. Since then, the contour line method has become the basic method for large-scale topographic mapping to display landforms.

Explain the concept and characteristics of contour lines.

Contour line: is a closed curve of adjacent points of equal elevation on the ground.

Contour Characteristics:

1) The elevations of points on the same contour line are equal;

2) Contours are closed curves;

3) Contour lines of different elevations cannot intersect;

4) The contour line is orthogonal to the ridge line and the valley line;

5) The vertical distance between two contour lines is called the horizontal distance, and the size of the horizontal distance between the contour lines is inversely proportional to the size of the ground slope.

The characteristics of contour lines include:

On the same contour, the height of any point is equal;

The difference in height between adjacent high lines is also the same;

The horizontal spacing of the contour lines can indicate the steepness or gentleness of the terrain;

Contours are closed or continuous curves;

Contour lines generally do not overlap or intersect.

Contour line definition.

A contour line is a closed curve of adjacent points of equal elevation on the ground, and the elevations are integers (whole meters, whole decimeters).

The use of contour lines to represent the landform on the topographic map can not only accurately reflect the ups and downs of the ground, the direction of the mountains, the shape of the mountains, the size of the slope, and the width and depth of the valleys, but also clearly show the general appearance of the mountains in a certain area.

Contour features.

Same line of equal height. Points on the same contour line are equal in height, with sea level as zero meters.

The contour distance is consistent across the map. Contour distance refers to the difference in height between two adjacent contour lines. For example, if the altitude of three contour lines is 500 meters, 600 meters, or 700 meters, the contour distance is 100 meters.

Contours are closed curves. No matter how twists and turns, they will eventually form a circle, but they may not all be closed in one picture.

Two contour lines must never intersect. Because in general, there will not be two heights in the same place. But in vertically walled cliffs, the contour lines can coincide.

The contour line is dense and reflects the steepness of the slope. Where the contour lines are sparse, a gentle slope is indicated by dense areas, and a uniform slope is indicated where the contour lines are equally spaced.

When the convex sides of the two pairs of contour lines are symmetrical with each other, it is the saddle of the mountain, and it is also called the pass of the mountain.

The slope line indicates the direction of the descent. The slope line is perpendicular to the contour line** and always points to the lower elevation, sometimes called the descending grade.

Several special contour lines. The 0-meter line represents sea level, which is also the coastline; The 200-meter line distinguishes between plains and low hills; The 500-meter, 1000-meter lines show low hills or plateaus; The 2,000-meter and 3,000-meter lines reflect the middle mountains and plateaus; The 4,000 meters reflect the characteristics of the Tibetan Plateau and high mountains. (Look).

(1) The elevation of any point on the same contour line is equal.

2) The height difference between adjacent contour lines is equal. The amount of horizontal spacing of contour lines indicates how gentle or steep the terrain is.

3) Contour lines are continuous, closed curves.

4) Contour lines generally do not intersect or overlap (except for cliffs).

5) Contour lines cannot cross the river valley embankments and roads on the drawings.