Contours — which is considered the best general method for interpolating contour positions between known points in practical mapping? Choose the most appropriate technique.

Introduction / Context:
Contour interpolation converts spot levels into continuous contour lines representing equal elevations. In practical topographic drafting, speed and reasonable accuracy are both critical, so the choice of method directly affects productivity and quality.

Given Data / Assumptions:

• We seek a generally preferred method in routine mapping.
• Trade-offs: speed vs accuracy vs resources.
• Techniques available: estimation, graphical, computation.

Concept / Approach:
Estimation is quick but subjective; computation is accurate but time-consuming. Graphical methods (e.g., proportional division along lines between known levels) balance accuracy and efficiency, making them the preferred general-purpose approach in manual/plan-based workflows.

Step-by-Step Solution:

Verification / Alternative check:
Survey drafting guides recommend graphical interpolation for routine mapping jobs due to its balanced accuracy and speed.

Why Other Options Are Wrong:

• Estimation: Excessively subjective.
• Computation: Overly time-intensive for most mapping scales.
• All of these: Not precise—one method is generally preferred.

Common Pitfalls:
Over-reliance on estimation leading to uneven contours; ignoring proportional rules along breaklines and spot levels.

Final Answer:
Graphical methods (e.g., proportional interpolation on plan)