Lecture 5 23/01/2017 (Part B)

Question 1

What is a Coordinate System?

Answer 1

1. A coordinate system is a reference system used to represent the locations of geographic features, imagery, and observations (e.g., Lat/long, Eastings/Northings, etc.)

Question 2

What are the 4 components of a coordinate system?

Answer 2

1. measurement framework - 2D (map) or 3D (globe)
2. Units of measurement (e.g., Lat/long, DD)
3. A defined map projected coordinate system
4. Reference/Control Points (e.g., datums, benchmarks, meridians, parallels)

Question 3

What does a projection system do?

Answer 3

It determines how a 3D surface will be transposed onto a 2D surface.

Question 4

What are the 2 type of coordinate systems?

Answer 4

1. Unprojected Coordinate Systems for unprojected maps.

2. Projected Coordinate Systems for projected maps.

Question 5

How to determine longitude and latitude.

Answer 5

Latitude - the angular distance measured from the centre of the earth between between the the equator and the line of latitude in question.

Longitude - the
angular distance, measured from the centre of the earth between the prime meridian and the line of longitude in question/

Question 6

What’s an example of a local Geographic Coordinate System? How do you determine your location?

Answer 6

1. UTM

2. Find your zone (Windsor = 17N) and then determine eastings and northings.

Question 7

What’s an example of a Cartesian grid based Coordinate System?

Answer 7

State Plane.

Question 8

What’s an example of spatial meta data without coordinates?

Answer 8

Postal Code

Question 9

What are the 4 uniformity variables (spatial properties) of map projection systems?

Answer 9

1. Conformity/Shape (maintains angles – so N/S, E/W lines intersect at 90 degrees – but at expense of distance = Conformal
2. Area (areas have proportional relationships to their corresponding features on the Earth) = Equal Area
3. Distance (maintains equidistance relationships, so distance from centre is the same no matter what direction) = Equidistance
4. Direction (maintained when angles are portrayed correctly in any direction) = Azimuthal

Question 10

What are the 3 main projections? Provide an example of each.

Answer 10

1. Cylindrical Projection (e.g., UTM); CA (near the equator)
2. Azimuthal Projection (e.g., Lambert Equal Area); Dist.
3. Conic Projection (e.g., Lambert Conformal) CADi.

Question 11

What are the properties of a Cylindrical Projection?

Answer 11

1. Continuous picture of the earth
2. Countries near the equator in true relative positions
3. View at the poles is very distorted
4. Area for the most part is preserved
   e. g., UTM

Question 12

What are the properties of an Azimuthal Projection?

Answer 12

1. Part of Earth is visible, half of globe or less.
2. Distortion occurs the edges
3. Distance is for the most part preserved
4. Mainly used for polar research.
   e. g., Lambert Equal Area

Question 13

What are the properties of a Conic Projection System?

Answer 13

1. Area is distorted
2. Distance is very distorted towards bottom of image
3. Scale is for the most part preserved
4. Scale and distance are distorted north to south, but maintained west to east.
5. Areas are proportional and the directions are true.
6. captures the whole continent.
   e. g., Lambert Conformal