Correct Option: A. Prismatic compass survey Explanation of the Correct Answer A prismatic compass survey is a method used in surveying that employs a prismatic compass to measure angles and bearings accurately. This technique is particularly effective for creating detailed and accurate contoured maps of small areas for several reasons:

1. Precision in Angle Measurement: The prismatic compass allows surveyors to measure angles with high precision. This is crucial for contour mapping, where the accurate representation of elevation changes is necessary.
2. Field Work Efficiency: The prismatic compass is lightweight and portable, making it easy to use in the field. Surveyors can quickly set up and take measurements, which is beneficial when mapping small areas where time and accuracy are critical.
3. Direct Measurement of Elevation: When combined with leveling techniques, the prismatic compass can help determine the elevation of various points in the surveyed area. This is essential for creating contour lines that represent different elevations on a map.
4. Visual Representation: The compass provides a clear visual representation of the area being surveyed, allowing surveyors to make immediate adjustments and corrections as needed.

Why Other Options Are Weaker B. Land-use survey: - A land-use survey focuses on categorizing and analyzing how land is utilized (e.g., residential, commercial, agricultural). While it provides valuable information about land use patterns, it does not specifically address the topographical features or elevation changes necessary for creating a contoured map. Therefore, it is not suitable for producing accurate contour maps. C. Plane-table survey: - A plane-table survey involves drawing the map directly in the field using a plane table and sighting instruments. While it can produce reasonably accurate maps, it is less precise than a prismatic compass survey for contour mapping. The accuracy of the plane-table survey can be affected by the skill of the surveyor and the conditions in the field, such as visibility and terrain. D. Chain survey: - A chain survey uses a measuring chain to determine distances and relies on triangulation for plotting points. While it can be useful for mapping larger areas, it is less effective for small areas where elevation changes are significant. The chain survey does not provide the same level of detail in angle measurement as the prismatic compass, making it less suitable for creating accurate contour maps. Summary of Key Points

• The prismatic compass survey is the most accurate method for creating contoured maps of small areas due to its precision in angle measurement and elevation determination.
• Other methods like land-use surveys, plane-table surveys, and chain surveys do not focus on topographical accuracy and are less effective for contour mapping.
• The prismatic compass is portable and efficient, making it ideal for fieldwork in small areas.
• Understanding the strengths and weaknesses of each surveying method is crucial for selecting the appropriate technique for specific mapping needs.

This thorough understanding will help you in your geography studies and professional exams.