Lecture 3 16/01/2017 (Part A)

Question 1

In-situ data collection, what is it, give examples.

Answer 1

Data collection (i.e., coordinates, elevations, information etc.) completed directly within an area of study (e.g., census date collection, surveying, etc.)

Question 2

Who launched the first NAVSTAR and when?

Answer 2

1960 US DND launches first ever NAVSTAR

Question 3

__-__ satellites in view of GPS at any one time, more is better

Answer 3

4 - 12

Question 4

What type of clock do GPS satellites utilize?

Answer 4

an atomic clock

Question 5

What is a GPS correction facility?

Answer 5

A control point that helps to make GPS signals more accurate.

Question 6

provide an example of “in-situ” data collection

Answer 6

surveying

Question 7

What are the components of surveying equipment?

Answer 7

(Total station) theodolite, stadia rod

Question 8

What is a Smart Station?

Answer 8

Total station that uses GPS rather than monuments to determine heights AMSL

Question 9

Census

Answer 9

An official count or survey of an entire population (complete enumeration), capturing select data about individuals within that population.

Question 10

Sampling

Answer 10

A sample is a select portion of a data set chosen to represent the entire data set (partial enumeration).

Question 11

What happened in 2011 to the census?

Answer 11

Went from a long form census to a short form census.

Question 12

What are the 3 segments of a GPS (Global Positioning System)?

Answer 12

1) space segment (i.e., satellites)
2) control (points) segment (e.g., the CG station Alice described to correct measurements to make them more accurate than otherwise)
3) user segment (i.e., the person with the handheld device)

Question 13

What do all satellites have to account for relativity?

Answer 13

An atomic clock

Question 14

Orbit at _______ km; 1

revolution per ___ hours

Answer 14

1. 20,000 KMs

2. 12 hours

Question 15

What are the 3 pieces of information a GPS uses to determine position?

Answer 15

1. Position (latitude and longitude)
2. Velocity
3. Time.

Question 16

What are sources of error for a GPS?

Answer 16

1. Sat. clock (sat. is moving quick, smallest error = chaos theory)
2. Ephemeris data (sat. current and predicted location, timing and “health”).
3. Atmospheric (layers of the atmosphere skewing the signal)
4. Receiver Error
5. Selective availability (availability of sats.)

Question 17

What 3 items comprise a total station?

Answer 17

1. An electronic theodolite (transit);
2. An electronic distance measuring device (EDM); and
3. Software running on an external computer, such as a laptop or data collector.

Question 18

Smart Station

Answer 18

A total station that uses GPS, no laser required.

Question 19

What is digitizing in GIS?

Answer 19

Digitizing in GIS is:

1. The process of converting geographic data either from
2. a hardcopy or a scanned image into
3. vector data by
4. tracing the features.
5. During the digitzing process, features from the traced map or image are captured as coordinates in
6. either point, line, or polygon format.

Question 20

What are the 3 Positional Errors with Manual Digitizing

Answer 20

1. Map: distorted scale, grainy resolution, poor quality, etc.
2. Process: Incorrect translation of control points
3. User: Shaky hands, inexperience.