What do you think of contour topographic map?

The contour topographic map is viewed from the following aspects:

Digital size

1. Plain: elevation

2. Hills: 200m

Contour topographic map, with sparse contour lines and gentle bends.

3. Mountain: 500 meters above sea level and 200 meters above relative height; The contour lines are dense and the valley is V-shaped.

4. Plateau: elevation >; 500 meters, high altitude, relatively small height, dense contour lines at the edge, and obviously sparse at the top.

Density degree

Dense: steep slope;

Sparse: the slope is gentle.

Shape feature

① Peak value: the contour line is closed, and the value gradually decreases from the center to the periphery (the contour line is closed, the value is high in the middle and low around).

② Basin or depression: The contour line is closed, and the value gradually increases from the center to the periphery.

(If there is no numerical note, it can be judged according to the slope indicator line: (Slope indicator line-a short line perpendicular to the contour line)

③ Ridge: The protruding part of contour points to a lower altitude. The contour line rises from high to low, which is the ridge.

④ Valley: The protruding part of contour line points to a higher altitude. The contour line from low to Shangsheng Gao is the valley.

⑤ Saddle: the blank part between the contour lines of two opposite ridges or valleys. Shaped like a saddle.

⑥ gentle slope, steep slope and steep cliff: the place where contour lines overlap is the cliff. The denser the contour, the steeper the terrain; The thinner the contour line, the gentler the slope.

Contour map view summary:

Look at the map, the upper north is the south, the left west is the right east, and the map orientation has been determined.

Color recognition of map symbols;

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

Contours show geomorphological features:

The contour is closed and regular, and the bending shape is as in situ; There are many mountains and high lines, few lines and low lines, and steep lines are dense and slow.

Principle of contour line displaying terrain;

From bottom to top, the height is equal; Horizontal incision, vertical projection.

Terrain recognition:

The small circle at the top of the mountain is concave, and the difference depends on the slope line; The short lines on the top of the mountain point outward, and the short lines on the concave land point inward;

The curve behind the mountain is convex outward, and the valley curve is curved inward; Ridge watershed and valley depression watershed;

Two mountains are connected, called saddle, with two sets of contour lines; At the highest point where mountains are connected, the ridgeline is called the ridgeline.

Law:

Low protrusion height (valley, high contour protrusion value, low actual height)

Low convexity means high convexity (ridge and contour lines have small convexity and high actual height).

Terrain fluctuation judgment:

Look at the landform generally and identify the height of each place; Distinguish between uphill and downhill, and write down the numbers along the way.

Distribution law of four topographic features:

Mountain clusters are like veins, and hills are mostly in the mountains; Grasp the mountain as the backbone first, and remember this pulse and that pulse.

The upstream is narrow and the downstream is wide, and many small rivers meet in Dachuan; Write the name of the river along the river, indicating the flow direction and velocity;

There are several bridges and ferries, and the depth and bottom materials should be familiar.

(3) roads

Plain land, many and wide, hilly land, narrow and few; If there are roads in mountainous areas, they should follow rivers and valleys.

(4) Residential area

The plains are dense and the mountains are sparse; Remember that there are rules in towns and villages; Bridges, castles, shops and towns depend on highways, and ditches, streams, ridges and valleys are in mountainous areas;

Looking for bubbles, bays, rivers, along the marshes, villages, villages, villages and kilns are scattered all over the place.