Global Positioning Subject Review 

1. The science of measuring and monitoring the size and shape of the Earth is 

___________________.

2. By looking at the height, angles and distances between numerous locations on the 

Earth’s surface, geodesists create a ___________________.

3. The Earth’s surface rises and falls about 30 ___________________. Everyday under 

the gravitational influences of the moon and the sun.

4. The Earth’s outermost layer is called the _________________.

5. The plates that make up the Earth’s outer layer ride atop a sea of molten rock called 

___________________.

6. Plate ___________________. is the scientific discipline that looks at how the Earth’s 

plates shift and interact, especially in relation to earthquakes and volcanoes.

7. The Greek philosopher ___________________ is credited as the first person to try 

and calculate the size of the Earth by determining its circumference.

8. A method of determining the position of a fixed point from the angles to it from two 

fixed points a known distance apart. _____________________

9. The Earth is flattened into the shape of an ________________ sphere.

10. To measure the Earth, and avoid the problems that places like the Grand Canyon 

present, geodesists use a theoretical, like the Grand Canyon present, geodesists use a 

theoretical, created by rotating an ellipse around its shorter axis.

11. To account for the reality of the Earth’s surface, geodesists use a shape called the 

___________________ that refers to mean sea level.

12. The earth’s mass is ___________________ distributed, meaning that certain areas of 

the planet experience more gravitational “pull” than others.

13. ___________________ are sets of data that are the basis for all geodetic survey 

work. In the United States, horizontal and vertical datums make up a system called 

the ___________________.

14. The ___________________ datum is a collection of specific points on the Earth that 

have been identified according to their precise northerly or southerly location and 

easterly or westerly location.

15. The northerly or southerly location of a point on the Earth’s surface is known as the 

point’s __________________.

16. The easterly or westerly location of a point on the Earth’s surface is known as the 

point’s ___________________.
17.Surveyors markpositions with brass discs or monuments called _________________.

18.Surveyors now rely almost exclusively on the ____________ to identify locations on 

the Earth.

19. The ___________________ is where two plates of the Earth’s crust meet, and is 

responsible for many earthquakes in California.

20. The ___________________ datum is a collection of positions whose heights above or 

below mean sea level is known.

21. The traditional method for setting vertical benchmarks is called _________________ 

leveling subsidence land sinking

22. Gravitational attraction between two bodies is stronger when the 

___________________ of the objects are greater and closer together.

23.Because the Earth’s mass and density vary at different locations on the planet, 

___________________ also varies.

24. In areas where the Earth’s gravitational forces are weaker, mean sea level will 

___________________.

25. ___________________ measure the gravitational pull on a suspended mass.

26. ___________________ established the Survey of the Coast, which later evolved into 

the National Geodetic Survey.

27. The National Geodetic Survey uses markers made from long steel rods driven to 

___________________ (pushed into the ground until they won’t go any farther).

28. GPS receivers calculate the distance to GPS satellites by measuring 

___________________.

29. GPS satellites have very precise clocks that tell time within three nanoseconds or 

three ___________________. (0.000000003) of a second.

30. ___________________ is a network of hundreds of station ary permanently 

operating GPS receivers throughout the United States that can be used to accurately

determine position.

31. In a ___________________, specific information about a place—such as the locations 

of utility lines, roads, streams, buildings, and even trees and animal populations—is 

layered over a set of geodetic data.

 
 Geodesy Subject Review: Crossword Puzzle 
Across

2. The Earth is flattened into the shape of an _____ sphere.

8. The plates that make up the Earth’s outer layer ride atop a sea of molten rock called 

_____.

10. _____ are sets of data that are the basis for all geodetic survey work.

12. In areas where the Earth’s gravitational forces are weaker, mean sea level will _____.

14. Established the Survey of the Coast, which later evolved into the National Geodetic 

Survey. [2 words]

15. In the United States, horizontal and vertical datums make up a system called the 

_____. [abbrev]

17. The easterly or westerly location of a point on the Earth’s surface is known as the 

point’s _____.

22. The Earth’s surface rises and falls about 30 _____ everyday under the gravitational 

influences of the moon and the sun.

24. The _____ is where two plates of the Earth’s crust meet and is responsible for many 

earthquakes in California. [3 words]

27. The traditional method for setting vertical benchmarks is called _____ leveling.

29. land sinking

31. The Earth’s outermost layer is called the _____.

32. The northerly or southerly location of a point on the Earth’s surface is known as the 

point’s _____.

Down 

1. By looking at the height, angles and distances between numerous locations on the Earth’s 

surface, geodesists create a _____. [3 words]

3. A method of determining the position of a fixed point from the angles to it from two fixed 

points a known distance apart.

3. __________ results in an overproduction of organic matter, especially algae.

4. Surveyors markpositions with brass discs or monuments called _____.

5. GPS satellites have very precise clocks that tell time within three nanoseconds or three 

_____ (0.000000003) of a second.
6. The Greek philosopher _____ is credited as the first person to try and calculate the size 

of the Earth by determining its circumference.

7. Plate _____ is the scientific discipline that looks at how the Earth’s plates shift and 

interact, especially in relation to earthquakes and volcanoes.

9. The Earth’s mass is _____ distributed, meaning that certain areas of the planet 

experience more gravitational “pull” than others.

11. The _____ datum is a collection of positions whose heights above or below mean sea 

level is known.

13. The _____ datum is a collection of specific points on the Earth that have been identified 

according to their precise northerly or southerly location and easterly or westerly location.

16. To account for the reality of the Earth’s surface, geodesists use a shape called the 

_____ that refers to mean sea level.

18. Gravitational attraction between two bodies is stronger when the _____ of the objects 

are greater and closer together.

19. Surveyors now rely almost exclusively on the _____ to identify locations on the Earth. 

[abbrev]

20. Because the Earth’s mass and density vary at different locations on the planet, _____ 

also varies.

21. The National Geodetic Survey uses markers made from long steel rods driven to _____ 

(pushed into the ground until they won’t go any farther).

23. _____ is a network of hundreds of stationary permanently operating GPS receivers 

throughout the United States that can be used to accurately determine position. [abbrev]

25. In a _____, specific information about a place—such as the locations of utility lines, 

roads, streams, buildings, and even trees and animal populations—is layered over a set of 

geodetic data. [abbrev]

26. The science of measuring and monitoring the size and shape of the Earth.

28. _____ measure the gravitational pull on a suspended mass.

30. To measure the Earth, and avoid the problems that places like the Grand Canyon 

present, geodesists use a theoretical, mathematical surface called the _____ that is created 

by rotating an ellipse around its shorter axis.

33. GPS receivers calculate the distance to GPS satellites by measuring _____.