The image shows a set of questions related to topographic maps, specifically focusing on the “Greasewood Spring, Arizona” quadrangle. This exercise is part of a geography or earth science course, dealing with map reading and interpretation.
Answer and Explanation for Each Question:
Q1: What is the contour interval of the map?
- Answer: The contour interval is the vertical distance or difference in elevation between contour lines on a map.
- Explanation: Contour intervals are used to represent the terrain’s elevation changes. The specific interval would be found in the map legend.
Q2: What is the difference in elevation between index contours?
- Answer: This is typically a multiple of the contour interval.
- Explanation: Index contours are bold lines on a map that are labeled with their elevation. The difference is usually five times the contour interval.
Q3: What is the elevation of the highest contour line at the top of the eastern Twin Butte?
- Answer: This would be the highest labeled contour line on the map.
- Explanation: To find this, locate the eastern Twin Butte on the map and identify the highest contour line.
Q4: What do the dashed blue lines represent?
- Answer: Dashed blue lines typically represent intermittent streams.
- Explanation: On topographic maps, different line styles indicate various features. Dashed blue lines often indicate streams that do not flow year-round.
Q5: What do the gray lines around and between the Twin Buttes represent?
- Answer: These lines could represent roads or trails.
- Explanation: Gray lines on maps often indicate man-made features like roads or paths.
Q6: What is the name of the adjoining quadrangle to the south?
- Answer: This would be the name of the map directly south of the current quadrangle.
- Explanation: Quadrangle maps are part of a grid, and each has a specific name. Check the map’s margin for adjoining quadrangles.
Q7: Why is this called a “7.5 minute” topographic map?
- Answer: It covers 7.5 minutes of latitude and longitude.
- Explanation: “Minute” refers to a unit of angular measurement. A 7.5-minute map covers an area of 7.5 minutes of latitude by 7.5 minutes of longitude.
Q8: What was the difference in degrees between true north and magnetic north for this map?
- Answer: This is known as magnetic declination.
- Explanation: Magnetic declination is the angle between magnetic north and true north. It is usually indicated on the map.
Q9: Why is “0” not at the far left on all three graphic scales?
- Answer: This is due to the map’s scale representation.
- Explanation: The graphic scale may start at a non-zero point to provide a more useful range for measurement.
Q10: Determine the maximum width of the eastern Twin Butte using the 6100′ contour.
- Answer: This would be the horizontal distance across the 6100′ contour line.
- Explanation: Use the map’s scale to measure the distance across the contour line and convert it to feet and kilometers.
Steps for Solving:
- Identify Map Features: Use the map legend to understand symbols and lines.
- Measure Distances: Use a ruler and the map’s scale to measure distances.
- Calculate Elevations: Use contour lines and intervals to determine elevations.
- Interpret Map Data: Use the map’s information to answer questions about geographic features and measurements.
These steps and explanations provide a framework for understanding and solving topographic map problems.