Question

Which characteristics of contour lines are true?
• Contour lines cannot cross each other in general
• Contour lines close together indicate steep slope
• A close contour line with lower value inside represents a hill
• A close contour lines with higher value inside represents a valley
• Contour lines spaced far together indicate a gentle slope Choose the correct answer from the options given below:

• A. A, B, C Only
• B. C, D, A Only
• C. B, C, D Only
• D. A, B, E Only

Hint:

Close contour spacing indicates steep slope, while wide contour spacing indicates gentle slope. Higher contour values toward center indicate a hill; lower values toward center indicate a depression.

Answer 1

The Correct Option is D

Concept: Contour lines are imaginary lines joining points having equal elevation above a reference datum. Contours are extensively used in surveying, topographic mapping, watershed analysis, irrigation planning, and civil engineering projects. Important properties of contour lines help engineers understand terrain characteristics such as slopes, hills, valleys, ridges, and depressions.

Step 1: Examine Statement A. Statement A: \[ \text{Contour lines cannot cross each other in general} \] This statement is correct because:
• A single point on ground cannot have two elevations simultaneously.
• Therefore, two contours of different elevations cannot intersect. Hence, \[ \boxed{\text{Statement A is TRUE}} \]

Step 2: Examine Statement B. Statement B: \[ \text{Contour lines close together indicate steep slope} \] This statement is correct because:
• Elevation changes rapidly over short horizontal distance.
• Hence contours become crowded. Therefore, \[ \boxed{\text{Statement B is TRUE}} \]

Step 3: Examine Statement C. Statement C: \[ \text{A close contour line with lower value inside represents a hill} \] This is incorrect. For a hill:
• Elevation increases toward the center.
• Therefore inner contours have higher values. Hence, \[ \boxed{\text{Statement C is FALSE}} \]

Step 4: Examine Statement D. Statement D: \[ \text{A close contour line with higher value inside represents a valley} \] This is also incorrect. Higher values inside indicate a hill, not a valley. Valleys generally have V-shaped contours pointing upstream. Thus, \[ \boxed{\text{Statement D is FALSE}} \]

Step 5: Examine Statement E. Statement E: \[ \text{Contour lines spaced far together indicate a gentle slope} \] This statement is correct because:
• Elevation changes slowly,
• Horizontal distance between contours becomes large. Therefore, \[ \boxed{\text{Statement E is TRUE}} \]

Step 6: Identify the correct combination. The true statements are: \[ A,\ B,\ E \] Hence, the correct option is: \[ \boxed{(D)\ A,\ B,\ E\ Only} \]