A series of closed contour lines on the map with lower to higher varies inside them, represents a
Hill
Contour Lines on a Map Explained
Contour lines are essential tools in cartography, used to represent the three-dimensional shape of the Earth's surface on a two-dimensional map. Each contour line connects points of equal elevation above a chosen reference datum, typically mean sea level. By studying the pattern and spacing of these lines, one can understand the terrain's slope, shape, and elevation.
Closed Contour Lines Interpretation
When you see a series of closed contour lines on a map, it indicates either a peak (like a hill or mountain) or a depression (like a basin or a sinkhole). The key to distinguishing between these landforms lies in how the elevation values change as you move from the outermost closed contour line towards the innermost one.
Hill: Identifying Elevation Changes
A hill is a natural elevation of the earth's surface, smaller than a mountain. On a topographic map, a hill is distinctly represented by a series of closed contour lines where the elevation values progressively increase towards the center. This pattern signifies that the land is rising towards a summit. Therefore, if the contour lines show "lower to higher varies inside them," it unequivocally points to a hill.
- The outer contour lines will always have lower elevation values.
- As you move inward towards the center, the numerical values of the contour lines will continuously increase.
- The innermost closed contour line represents the highest point or the peak of the hill.
Contour Patterns for Different Landforms
To further clarify, let's examine how other common landforms are depicted by contour lines:
| Landform | Contour Line Representation Characteristics |
|---|---|
| Hill | Series of closed contour lines with increasing elevation values towards the center (from lower outside to higher inside). |
| Ridge | Elongated, U-shaped, or V-shaped contour lines that typically point towards lower elevations (downhill). They represent a long, narrow elevation. |
| Depression | Series of closed contour lines with decreasing elevation values towards the center (from higher outside to lower inside). These are often marked with hachure lines (short lines perpendicular to the contour line, pointing inward) to denote a dip or hollow. |
| Steep Slope | Very closely spaced contour lines. The closer the lines are to each other, the steeper the terrain's gradient, indicating a rapid change in elevation over a short horizontal distance. |
Landform Representation by Contour Lines
The question describes a scenario where "A series of closed contour lines on the map with lower to higher varies inside them." This specific arrangement of contour lines is the definitive characteristic of a hill. The rising elevation towards the center of the closed contours indicates an elevated landform, confirming that it represents a hill.
Important Questions from Contouring
Identify the correct statements.
i. Contour lines form sharp V-shaped curves across valley line, with the convex side of the curve towards the higher ground.
ii. Contour lines form U-shaped curves across valley line, with the convex side of the curve towards the higher ground.
iii. Contour lines form U-shaped curves across ridge line, with the concave side of the curve towards the higher ground.
iv. Contour lines form sharp U-shaped curves across ridge line, with the convex side of the curve towards the higher ground.
Two contour lines of same elevation:
The suitable contour interval for a map with scale 1:50,000 is
Contour lines cross a ridge or valley line at
_______ are lines drawn on a map to locate, in the plan view, points of equal ground elevation.
