What is the detailed explanation of the law of contours in geography?What are the various situations

Contours in geography are: isotherms, contours, isosalinity lines, and so on. 1. Where the contour line is dense, the difference within one unit is usually larger, and the difference within one unit is smaller in the place where the contour line is sparse.

It can be understood according to the specific contours, such as: isotherms, contour lines) 2, the law of high and low: in the contour closed area between two contours, if the value of the closed contour is equal to the lower contour, the value in the closed area is lower than the value of the closed contour;If equal to the higher contour, the value within the closed area is higher than the value of the closed contour.

Contours cannot coincide perpendicular or intersect (except for steep cliffs), and adjacent contour lines are equally equispaced. If there is a closed curve between two contours, the value within the closed curve is greater than the value of the largest contour adjacent to it, or less than the small one.

General rules for contour diagram interpretation.

1. Read the data (pay attention to the equivalence).

Same Line Equivalence: The values of each point on the same contour line are equal;

Adjacent contours: In general, the difference between two adjacent contours is the same or zero in the same contour map

High or Low Zone: A small closed area between two contour lines, indicating that the value is not within the normal range of the two line values, and the value within it can be interpreted as "greater than large" or "less than small", such as a peak or depression on a mountain slope.

2. Ratio size:

The size of the contour line is interpreted according to the distribution law of geographical elements, such as the height of the sun decreases from the direct point of the sun to the surroundingsThe pressure value of the cyclone's center is lower than that of the four weeks;

Compare the values of two points (or two regions) according to the trend of the contour line.

3. Look at the density (ratio difference).

On the same contour map, the denser the contour line, the greater the regional distribution of the geographic featureOn the contrary, the smaller the difference.

4. Judge the trend.

Isotherms decrease northward in the Northern Hemisphere and southward in the Southern Hemisphere;

Where does the maximum value appear, where does the lowest value appear, and what is the trend from high to low or low to high?For example, the amount of precipitation in China decreases from the southeast coast and the northwest inland.

5. Analysis and bending.

The contour line is small where the contour curves in the direction of the large value, and the value is large where the contour line bends in the direction of the small value, for example, in the contour diagram, the high line bends to the high place for the valley, and the contour line bends to the low place for the ridge.

The curvature of the contour reflects that the distribution of geographical elements is affected by certain factors, such as the curvature of the isotherm will be affected by the distribution of land and sea, topography, ocean currents, surface vegetation, urban construction and other factors.

6. Identify the direction:

Look at the direction of direction or extension, such as judging the direction of a mountain range;

Judge the slope direction on the contour (depth) line and the wind direction on the isobar. The aspect is directed from high to low, perpendicular to the contour line;The near-surface wind direction shifts from high pressure to low pressure, diagonally with the isobar, with the northern hemisphere skewing to the right and the southern hemisphere skewed to the left.

There are three main aspects of the distribution law and characteristics of contours: 1Numeric value, i.e., the difference in the value of the contour line on the contour map;2.Sparseness, in the regional differences of a certain geographical feature, the contour sparse difference is small, and the contour line is dense and the difference is large.

3.Bending, convex low is high, convex high is low.

The contour line is a smooth curve formed by the points of a certain quantity index value of the cartographic object, which is drawn by the points marked on the map indicating the number of cartographic objects, and the integer points are found by the interpolation method. In the compilation of contour maps, the values of the relative points (stations) of the cartographic objects are usually marked on the geographical base map, and then the points with equal values are connected into a smooth curve to outline the spatial structure characteristics of the cartographic objects. Common are: isotherms, isobars, contours, contours, etc.

1.Describe a specific line, such as an isotherotherm: it can be considered in terms of protrusion, extension direction, protrusion (bending) direction;Observe whether there is an inflection point, and if there is an inflection point, describe it in segments.

2.Describe the overall distribution characteristics of multiple contour lines and linear geographic things:

Describe the distribution characteristics of multiple contour lines: density + trend + numerical change.

Describe the distribution characteristics of multiple linear geographical things: progressive trend + numerical range + extreme value.

1) Describe the maximum and minimum values:

Where are the centers of low or high values distributed?What is the value?

2) Describe the trend of numerical changes:

Increasing or decreasing from which direction;

From how much to increase (decrease) to how much (or between how much to how much) 3) Describe the density:

The distribution is dense or sparse, and the difference in unit distance is large or small.

4) Describe the extension direction available:

In the direction of latitude (east-west);along the meridian (north-south) direction;

along the river; along the terrain; along the coast and much more.

5) Describe the bending bump can be used to:

protruding (convex) towards the low latitudinal process; protruding (convex) towards high latitudes; convex to the south; convex to the north;

to high altitudes; to low altitudes; upstream of the river; downstream of the river, etc.

Look at the circle of lines, the same circle is the equivalent.