Section 2.1

Question 1

What is the difference between a map and an aerial photo?

Answer 1

Maps use symbols, and aerial photos have real life details

Question 2

Define Photo Interpretation.

Answer 2

The process of identifying objects or conditions in aerial photographs and determining their meaning or significance.

Question 3

What are the photo interpretive elements? (8)

Answer 3

Shape
Size
Tone/colour
Texture
Pattern
Shadows
Association/site
Time

Question 4

What is aerial photography?

Answer 4

A form of remote sensing that takes an over head image of the land

Question 5

What does looking at shape reveal about land use?

Answer 5

Geometric characteristics, can indicate if it is natural or man made.

Question 6

What can size say about land use?

Answer 6

Comparative volume shows what percentage of land is used for what.

Question 7

What does tone/colour say about land use?

Answer 7

Shades of grey can show how much light is reflected back from a surface. Colour can indicate where specific wavelengths are stronger.

Question 8

What does texture reveal about land use.

Answer 8

Texture can indicate what is in the land smooth being water or ice, course being vegetation.

Question 9

What does shadow indicate about a land use or objects?

Answer 9

Shadow provides information about an objects height, orientation and shape

Question 10

What does site indicate about land use?

Answer 10

Looking at different locations compared to one another to establish possible relationships

Question 11

What does time tell us about land use images.

Answer 11

It shows development over time.

Question 12

What do focal lenses effect?

Answer 12

The angular field of view, meaning you can see more area.

Question 13

By increasing your angular field of view you can fly at a ______ altitude.

Answer 13

Lower

Question 14

A wide focal lens means there will be a ________ focal length and a ________ larger angle view.

Answer 14

Shorter, larger.

Question 15

Which is correct:

Scale = focal length / flying height

Scale = flying height / focal length

Answer 15

Scale = focal length / flying height

Question 16

Label the variables in this equation.

RF = PD / (MDxMS)

Answer 16

RF = scale 
PD = photo distance between points 
MD = map distance between points 
MS = map-scale denominator

Question 17

What are fiducial marks?

Answer 17

Registration marks engraved on sides and corners of photographs

Question 18

Define the principal point.

Answer 18

The exact geometric point in the centre of a photograph found by joint adjacent fiducial marks

Question 19

What are the 3 types of centres in aerial photographs?

Answer 19

Principal point
Nadir
Isocenter

Question 20

Define Nadir.

Answer 20

It is a centre point in an aerial photo directly under the focal plane, relief displacement.

Question 21

Define Isocenter.

Answer 21

Tilt displacement, exactly half the distance between principal point and nadir.

Question 22

What makes a true vertical photograph?

Answer 22

All three centre points, principal point, nadir and Isocenter, are identical

Question 23

Label the variables:

VE = 0.076(B/H)(d•/be)s

Answer 23

VE = vertical exaggeration
B/H = base to height ratio , distance between two pp on overlapping photo.
d•= stereoscopic viewing distance ( viewing distance above the plane of the photo)
be= eye base ( distance between the centre of the oculars on the stereoscope) 
S = photo separation, distance between two photos

Question 24

Define vertical exaggeration.

Answer 24

Change in proportion of objects appearing in aerial photographs. Causes objects to appear higher and slopes greater than reality

Question 25

Define relief displacement

Answer 25

The displacement of a 3-D object on a photograph due to changes in height.

Question 26

Why does relief displacement occur?

Answer 26

3-D images being projected onto 2-D surfaces.

Question 27

Identify the variables:

d = r(h)/H

Answer 27

d = relief displacement 
r = distance from principal point 
h = height of object above surface 
H = flying height

Question 28

Define parallax.

Answer 28

The apparent displacement of an object caused by the movement of the observer relative to that object.

Question 29

Identify the variables:

h = (H)dP/ (Pb+dP)

Answer 29

h = height of object
H = flying height 
dP = parallax difference between top and bottom of an object
Pb = absolute parallax of an object base