All About Nautical Charts Tutorial: Subject Review

The following questions are based on information from the All About Nautical Charts tutorial. As you read through the tutorial, answer the questions that correspond to each section.

What are nautical charts?

1. How do nautical charts help people navigate while on the water?
2. How are nautical charts different from a road map that you might use while driving?
3. What are some examples of hydrographic information that you can find on a nautical chart?
4. What kind of professions use nautical charts?
5. How do nautical charts help make navigation safer?

What kind of information does a chart provide — what does it tell us?

6. Why are the symbols on a nautical chart important? How do they help navigators?
7. What kind of natural land features might appear on a nautical chart? What natural features in the water might be shown?
8. What kinds of human-made structures on land can appear on a nautical chart? What about human-made features in the water?
9. What is a compass rose, and how does it help navigators?
10. What is the difference between True North and magnetic north?
11. What is magnetic declination?
12. Why is it important to know what year a chart was created when using a compass?
13. What are lines of latitude and longitude? Why are they important?

What is nautical cartography?

14. What is the difference between cartography and nautical cartography?
15. How do nautical cartographers use their best judgment when creating nautical charts?
16. How can natural processes, like storms or erosion, change the environment over time?
17. How can people and their activities change the environment over time?
18. Why is it important to update nautical charts regularly?
19. What kinds of features are often updated on nautical charts?
20. About how many charts do NOAA staff produce each year?

What is hydrography?

21. What kinds of information can hydrographic data tell us about the ocean?
22. Why is it important for scientists to collect measurements of the seabed?
23. What types of information do scientists collect during a hydrographic survey?

What’s the difference between hydrography and oceanography?

24. What is the difference between oceanography and hydrography? 
25. What are some of the interdisciplinary topics within oceanography?
26. What is an example of an aspect of oceanography that is essential to hydrography?

What tools do hydrographers use?

27. What are the two types of lasers that lidar systems use? What does each one measure?
28. What kinds of features can topographic laser scanners measure?
29. What are tide and water level datums? Why are they important?
30. Why is it important to know the exact location where data is collected when creating a nautical chart?
31. Why do sonar systems use sound waves to detect features underwater?
32. What are speed profilers? Why do scientists use them?
33. What is the difference between single-beam and multibeam sonar systems? 
34. What kinds of information can you learn from a bathymetric map?

Waves, tides, currents, and hydrography

35. How are ocean waves formed?
36. Does the sun or the moon exert a greater gravitational force on the ocean? Why?
37. What factors affect the direction and strength of ocean currents? 
38. How can ocean currents affect the way vessels navigate?
39. Why is it important for nautical charts to include information about water depth?
40. What is a tidal datum? How are they created?
41. What is the National Tidal Datum Epoch? Why is longer-term tidal data important to scientists?

What is the history of U.S. chart-making? (Early years)

42. Where did the information for the first U.S. nautical charts come from?
43. Which U.S. president was authorized by Congress to commission a survey of U.S. coasts?
44. What year was the Office of Coast Survey established? Where was the first hydrographic survey conducted?
45. What area of the U.S. did the first nautical chart show?
46. Describe how sailors measured water depths in the early 1800s.
47. What techniques did surveyors use to calculate a schooner’s position while at sea? What method did they use when the vessel was closer to shore?

What is the history of U.S. chart-making? (Middle years)

48. Why did nautical chart production increase drastically between 1941 and 1945?
49. What is the Hydroplot system? On what survey vessel was the system first installed?
50. Why was the Coast and Geodetic Survey office split in 1970? What offices were created?
51. Why did the Hydroplot system eventually stop being used?

What is the history of U.S. chart-making (Later years)

52. What kind of data could the Hydrographic Data Acquisition and Processing System acquire and process?
53. What kind of information did the Differential Global Positioning System provide?
54. What challenges do scientists face when working with the large amounts of data collected today?

What is the future of U.S. nautical chart-making?

55. When did NOAA begin converting paper charts into electronic navigational charts, or ENCs?
56. What are some advantages of using ENCs?
57. When were all NOAA paper charts phased out?