Photogrammetry Final Practice Questions

The primary land use to which forest has been converted in the U.S. in the last two hundred years is ________

agriculture

Spatial arrangement of objects is ______

pattern

As parallax goes up, scale ______

gets larger

sunlight on water is an example of ______

specular reflection

What are ways to obtain more photons on average?

increase width of wavelength bands

increase the size of the ground resolution cell

pure water has a ______ _________ in the shortwave infrared

low reflectance

improving the __________ resolution increases the number of gray levels in a wavelength band

radiometric

The two wavelength bands used by most vegetation indices are _______

red and near infrared

The computer chooses the spectral classes; the analyst assigns each spectral class to an informational class. This is an example of _________

unsupervised classification

Using the stereoscopic overlap area of a pair of vertical aerial photographs, the parallax at the ______ of the tree will be larger

Top

Which band to color assignment will result in deeper, darker shadows?

standard false color composite

What is the digit in the 2^4 place in 110011 base 2?

1

_________ can be made using digital stereo photography

topographic maps

Most airborne laser scanners used for forest inventory emit in the _______

NIR and green wavelengths

_______ are not strong absorbers in the near infrared

anthocyanins

blue skies are caused by ________

Rayleigh scattering

microwaves have _____________ than the red portion of the electromagnetic spectrum

less energy per quantum

“-ance”

unitless ratio

“taking in of energy at particular wavelengths by atmospheric constituents” refers to ________

absorption

If a classification scheme enables every possible land use to be labeled with a category is is called _________

exhaustive

A feature exhibits specular reflectance in the visible wavelengths.

It may not exhibit specular reflectance throughout the electromagnetic specturm

_________ refers to unpredictable diffusion of radiation by particles in the atmosphere

scattering

The speed of light is ________ in water than in the air

slower

The emissivity of a greybody is always _______

less than one

The best season to quantify the amount of hardwood lead area in a pine stand is _______

spring

Thinning a stand usually _________

decreases the simple ratio

Tree heights are systematically underestimated by _______

discrete return lidar

aerial photographs

LAI is _________ to the simple ratio for LAIs less than 3.5

linearly related

“transmittance + absorptance = reflectance” is

sometimes true

hierarchical

cannot tell if mutually exclusive

atmospheric walls in the optical portion of the electromagnetic spectrum are primarily caused by _________

water vapor

leaf reflectance in the green portion of the electromagnetic spectrum is usually _________

less than 20%

What are likely to cause variability in spectral signitures?

atmospheric effects

disease

drought

phenology

as a blackbody cools, _________

the wavelength at which it primarily emits increases

The units of analysis foresters use with lidar data are ______

grid cells

individual trees

stand or sub-stand objects

A four year old plantation appears magenta on a color infrared image acquired using a minus blue filter. What color will it be to our eyes?

green

_________ typically leads to an underestimate of discrete return lidar derived overstory tree heights when the understory is dense

Sensor dead times

Error propagation is usually larger with ___________ change detection

post-classification

for optimal remote sensing we prefer that the feature being imaged be _______ with respect to the wavelength of incident energy

rough

___________ has more NIR reflection than red spruce

white birch

techniques like unsupervised classification typically rely on which one of these characteristics shown to be useful in photointerpretation?

hue

A __________ is a group of pixels that are similar with respect to their reflectance

When was the Landsat program started?

1972

Data volume is higher with ____________ lidar data with the same pulse density

waveform

Lidar data are usually delivered as ________

x, y, z coordinates

It rains on a previously dry section of bare soil.

the NIR reflectance will decrease

Reflectance is _________

illumination invariant

P-band radar is being used to image the Brazilian Amazon in the wet season. What will happen as the P-band interacts with clouds?

Rayleigh scattering will happen

You take a picture of a green feature (to our eyes) with a color infrared sensor, but do not really know whether it is reflective in the photo IR. On a standard false color composite, it could be either _______

blue or magenta

Thinner spectral bands increases

spectral resolution

Assuming a constant flying height, focal length, and ground elevation ___________ will be constant in a vertical aerial photograph

scale

As frequency increases,

wavelength decreases

Rayleigh scattering can cause __________

haze in color photographs

Given healthy trees and the leaf-on condition, coniferous trees will have __________ than deciduous trees

less reflectance in the near infrared

In the red portion of the electromagnetic spectrum, bare soil is likely to be __________ than vegetation.

more reflective

A classification scheme should be ______

hierarchical

mutually exclusive

exhaustive

If the minimum mapping unit for forest is 40 acres, and you find a 39 acre forest in the middle of an otherwise agricultural area, you should label it ___________

forest

Leaves typically have more reflectance in the ________

NIR rather than green

A __________ is a group of pixels that are similar with respect to their brightness value vectors

spectral class

________ is the ecological state and physical appearance of the land surface

land cover

which wavelength range would likely be most helpful for drought stress detection in leaves?

shortwave infrared

why do we see vegetation as green?

plants absorb red and blue wavelengths for photosynthesis

under which of the following scenarios would a vegetation index be useful for estimating LAI?

low to moderate canopy cover

What is the most likely cause of the yearly cyclical variation in the vegetation index at Brush Mountain?

changes in how many leaves are on the trees

Why area areas such as the southeast showing an increase in forest coverage on non-forest to forest coverage change map?

forest cover increases after previous harvests

Lidar intensity is a measure of _______

the energy of the return at a particular time

Frequency of tonal change is ______

texture

As spectral resolution becomes finer ___________

spatial resolution must become coarser

increasing sensor dwell time will help with the _______

signal to noise ratio

A longer focal length will ________

decrease exposure

As F-stop increases,

Depth of field increases

Image distance will ______ when an object is at an effectively infinite distance o

equal focal length

The subtractive primary colors of light are ________

yellow, cyan, and magenta

Shadow are _________ in the green than they are in the NIR

more illuminated

The distance from the lens at which parallel light rays entering the lens are focused to a point is _______

focal length

the focal length divided by the __________ is equal to the scale at that point

height of the aircraft above the ground

Both CCD and CMOS sensors are sensitive to ________

near infrared energy

Increasing ISO will result in more _______

noise

(3 2) - (1 1) = (2 1)

This is a change detection (assume the four pixel images are acquired at 2 different dates) Into what general category of binary change detection does this operation fall?

Image algebra

The Landsat MSS had 64 gray levels. How many bits is that?

6

The raw ingredients for a successful digital photogrammetry project are

Ground control points

known exposure station locations and orientations

overlapping photographs

There can be _____ return per laser pulse

more than one

The analyst chooses the spectral classes and then labels them. This is an example of a __________

supervised classification

You decide to use the panchromatic band. Compared to the multispectral bands on the same sensor, its _________

spatial resolution is likely to be finer

In terms of overall radiative forcing, the most important greenhouse gas is _________

water vapor

A photon strikes a molecule resulting in an electronic energy transfer that increases kinetic energy.

This process describes absorption

Tree heights can be obtained ________

using a single photo

Advantages to UAV-collected data are:

cheaper

on-demand acquisition and processing

does shortwave IR or thermal IR have more energy per photon?

shortwave infrared

Landsat data has had shortwave infrared bands since the

1980s

Landsat 4 in 1982

Landsat 5 in 1984

Which of the following might interfere with the signal of interest in bitemporal spectral change detection

different seasons

varying moisture levels

what is an advantage of multitemporal spectral change detection?

ability to detect more subtle changes

Which are active sensors?

lidar

radar

Microwaving the cat is a bad idea becasue

photon flux density in microwaves is very high

focusing a camera changes

image distance

To obtain the ground ground X,Y, and Z of any place in stereo overlap you need

parallax

focal length

air base

height of plane above mean sea level

You decide to take a picture in low light without the flash but using the same f-stop and shutter speed.

The noise in the photograph will increase

Spaceborne hyperspectral data are ________

commonly available and suitable for routine analysis

You can estimate LAI of a stand using _________

both lidar and landsat data

which wavelength band would be better to separate vegetation from soils?

SWIR2