How do you judge terrain based on contour lines?

Interpretation of the five major terrains:

1)) Plateau: contour line.

The middle is sparse and dense, the altitude is more than 500 meters, the surface terrain is not very undulating, and the edge is steep;

2) Plain: The contour line is sparse and straight, the altitude is below 200 meters, and the surface is flat and broad.

3) Mountains: Contour lines are dense, altitude.

Above 500 meters, the surface slope is steep and the valley is deep.

4) Hills: the contour line is dense, the altitude is low, 200-500 meters lower, the relative height is not higher than 100 meters, the surface slope is peaceful, 5) the basin: the middle of the contour line is sparse and dense, the altitude is not standard, and the surface is high and low in the middle.

Interpretation of other small terrains:

1) Summit: Closed curve, the value gradually decreases from the center to the periphery or the slope line is drawn on the outside of the contour line, and the slope decreases to the outside;

2) Ridge: It is the convex part of the top of the mountain that sticks outward, and the contour line protrudes from the high place to the low place, and the middle part is higher than the two sides;

3) Valley (river valley): It is the low-lying part between the ridges, just opposite to the ridge, and the contour line protrudes from the low to the high;

4) Saddle: the area between the two groups representing the contour lines of the peaks, in the shape of a saddle, which is the highest part of the valley line and the lowest part of the ridgeline;

5) Cliffs: Where multiple contour lines overlap.

Summit: The contour line is closed, and the value gradually decreases from the center to the periphery.

Basin or depression: The contour line is closed and the value rises gradually from the center to the 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.

Look at the map to know the terrain.

Draw a straight line in the map of the contour line, establish a coordinate system, the ordinate is the height, and the transverse is obtained by the translation of the straight line, and the intersection of the straight line and the contour line in the map of the contour line is translated into the coordinate system, and then connected, and finally the terrain is judged.

Contour topographic maps are interpreted as follows:

1.Read the value. First, it is necessary to read the size of the regional terrain undulation; Second, the maximum and minimum values of altitude should be read. Terrain types can be identified based on numerical features.

2.Read the extension direction. The direction of the contour line is used to determine the direction of the terrain, such as the ridge trend.

3.Read the degree of density. According to the density of the contour line, the steep slope, the convex slope and the steep cliff are determined.

1) Dense and steep, the greater the spacing between the contour lines, the sparser the contour lines, the slower the slope. Conversely, the slope is steeper.

2) The slope is convex and concave. The contour line "high sparse and low density" is "convex slope", and "convex slope" cannot be seen. The contour line "high density and low sparseness" is a concave slope, and the concave slope can be seen.

4) Calculation of the height of the cliff:

The absolute height of the cliff top: a h (a d), where a is the maximum value of the altitude in the coincident contour line of the steep cliff, and d is the contour distance. As shown in Figure 6, the absolute height of cliff top a is: 400 ha 500.

Absolute height at the bottom of the cliff: (b d) h b, where b is the minimum value of the elevation in the coincident contour line of the cliff, and d is the contour distance. As shown in Figure 6, the absolute height of cliff bottom b is: 100 HB 200.

Relative height of the cliff: (n-1)d h (n+1)d, where d is the contour distance, and n is the number of coincident contour lines at the cliff. As shown in Figure 6, the relative height of the cliff is: 200 h 400.

4.Read the bending condition. Ridges, valleys, and saddles are determined based on the bending of the contour lines.

1) Interpretation of ridges and valleys:

2) Saddle interpretation " " lettering: between the contour lines of the two ridges or valleys facing each other is the saddle. As shown, the convex saddle is the saddle, and the contour line of the saddle is like the word "". The saddle is low-lying and tends to be a place where mountain roads pass.

Interpreting contour topographic maps:

1) Mountain top: also known as mountain peak, mountain range. In a contour topographic map, the contour values are high in the middle and low in the periphery.

2) Ridge: In the contour topographic map, the contour line bends from high to low.

3) Valley: In the topographic map of the ascending line, the contour line curves from low to high.

4) Basin: In the contour topographic map, the contour value is lower in the middle and higher in the periphery.

5) Saddle: The contour topographic map, the low point between two adjacent mountain ranges.

6) Steep cliffs: In the contour topographic map, the contour lines coincide.

7) Steep slope and gentle slope: In the same contour topographic map, the place where the contour line is dense is a steep slope; The sparse contour line is a gentle slope.

Many people don't know how to read contour charts, so I'm here to teach you how to recognize contour maps.

How it works:

Peak (peak): In the contour topographic map, the middle is high in the middle and low in the periphery, and the middle is the summit. Basin or depression: In the contour topographic map, the middle part is a basin if the value is lower in the middle and higher in the periphery.

Ridge: A ridge is the place where the contour line curves from high to low. The ridge is higher than the sides and is a watershed, so it is often the watershed of the river.

Valley: The place where the contour line curves from low to high, is the valley. A valley is a catchment line (catchment area) where water sources come together, so rivers are usually formed here.

Distinction between valleys and ridges: The contour line protrudes to the higher altitude of the valley, and the contour line protrudes to the lower altitude of the ridge, so "the convex height is the valley, and the convex low is the ridge".

Saddle: The empty part between two ridges or valley contours facing each other, (the lower part between two adjacent summits, named after the shape of a saddle.) It is also a low and shallow place between the two mountains on the ridge, but slightly higher than the col, and if the saddle terrain is narrow and deep, it is used as a road across the sides of the ridge, which is called a pass.

<> Cliff: When several contour lines of different elevations intersect in one place, the topographic part of the area is a steep cliff. A near-vertical hillside, where multiple contour lines overlap. The cliffs are suitable for rock climbing, and there may be waterfalls.

Contour topographic map viewing starts with the following aspects:

One. The magnitude of the value

1.Plains: < 200 meters above sea level; Contour lines are sparse.

2.Hills: 200 meters above sea level< 500 meters, relative height less than 200 meters.

Contour topographic map, the contour line is sparse, and the bends are gentle.

3.Mountains: more than 500 meters above sea level, relative altitude more than 200 meters; Contour lines are dense, and river valleys are present"v"Glyph.

4.Plateau: 500 meters above sea level, large altitude, small relative height, contour lines are very dense at the edges, and the top is obviously sparse.

Two. Density

Intensive: steep slope;

Sparse: Gentle slope.

Three. Shape features

Summit: The contour line is closed and the value gradually decreases from the center to the periphery, basin or depression: the contour line is closed and the value gradually increases from the center to the periphery (if there is no numerical annotation, it can be judged according to the slope line: (the slope line - ** perpendicular to the contour line).

Ridge: The contour protrusion points to a lower elevation. The high line of the isocurve 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 slope and steep slope and steep cliff: the contour line coincides with the cliff silver reed. The denser the high line of the isofrontal band, the steeper the terrain; The sparser the contour line, the more gentle the slope.

Expand your knowledge

One. Contour map view summary:

Facing the map, the upper north and lower are the south, the left west and the right are the east, and the map orientation has been identified.

1.Map Symbol Color Recognition:

Green is woodland, blue is water, landscapes and roads are painted brown, and other symbols are black.

2.Contour lines show geomorphological features:

Contour closure is regular, and the curved shape is like the spot; The line is more mountainous, the line is less high, the line is low, the slope is steep, the line is dense, and the slope is sparse.

3.Contour lines show the principle of the landform:

From bottom to top, equal height; Cut horizontally, projected vertically.

4.Geomorphological Identification:

The small circle of the concave land on the top of the mountain, the difference depends on the slope line; The top of the mountain ** points outward, and the depression ** points inward;

The back curve of the mountain is convex outward, and the curve of the valley is curved inward; The convex ridge waterline at the back of the mountain, the waterline at the concave bottom of the valley;

The two mountains are connected and called the saddle, and the high and low two groups of contour lines; The mountains are connected at the highest point, and the ridgeline is called the ridgeline.

5.Regularity:

The convex height is low (valley, contour contour convex value is large, the actual height is low).

The convex low is high (the ridge, the contour contour convex value is small, the actual height is high).

What should I pay attention to in the interpretation of contour topographic maps? I didn't tell you about it, but see below.

01 The numbers on the contour topographic map represent the altitude of the mountain, and some people will see these numbers as the difference in altitude between the mountains, which is not true, and the number on the top of each mountain indicates the height of the mountain Li Na itself.

02 Contour lines on contour topographic maps are generally closed, and if there is a place that is not closed, it means that it is a cliff.

03 Sometimes contour topographic maps show a curved line drawn on the mountain, and this line represents a river.

04 Contour lines generally do not overlap, if you find any overlapping contour lines, it means that there is a steep cliff here.