ENVSOCTY 3SR3 QUESTIONS AND ANSWERS
Remote Sensing - Answer -art, science and technology of obtaining reliable information
about physical objects and the environment, through the process of recording,
measuring and interpreting imagery and digital representation of energy patterns
derived from non-contact sensor systems
A RS instrument... - Answer -collects information about an object/phenomenon within
the instantaneous-field-of-view (IFOV) of the sensor system without being in direct
physical contact with it
IFOV - Answer -Instantaneous field of view
- angular size of ground area covered by single detector or pixel on sensor
Ground-projected IFOV is area on Earth's surface... - Answer -represented by a single
pixel in an image (essentially ground-sampling distance)
Remote sensing collections information about an ____________ or ____________ -
Answer -object, area
Object - Answer -e.g. the height of a tree crown
Area - Answer -e.g. geographic extent of a lake
RS Measurement are based on: - Answer -Electromagnetic Radiation
EM Spectrum is divided into... - Answer -regions based on how energy acts differently
when it interacts with features
EMR is either... (3) - Answer -- reflected
- emitted
- back-scattered
- depends on what type of radiation we are dealing with (everything on Earth's surface
interacts differently)
Name 6 Reasons for Use of Remote Sensing Data - Answer -- source of spatial and
temporal information
- monitor and develop understanding of environment
- timely information, consistent and cover large area
- availability of historical data
- quantitative applications (temp, gases, surface)
- commercial applications (weather, agriculture, management)
,Remote sensing information may be useful for modelling... (8) - Answer -- global
carbon cycle
- biology and biochemistry of ecosystems
- aspects of the global water and energy cycle
- climate variability and prediction
- atmospheric chemistry
- characteristics of the solid Earth
- population estimation
- monitoring land-use change and natural hazards
Name 10 advantages of remote sensing - Answer -- wide area coverage: potentially
large/inaccessible areas
- global and regional studies possible
- frequent and consistent data collection
- objective and reproducible
- multi-spectral and multi-temporal
- non-invasive and non-destructive
- cost-effectiveness to end users
- data integration and analysis
- rapid response to disasters
- enables operational efficiency
Name 11 limitations of remote sensing - Answer -- often oversold, doesn't provide all
the info needed to conduct research (not replacement for fieldwork)
- not direct, measures surrogate variables
- scale and context
- sensor design limitations
- atmospheric interference
- cloud cover and weather
- calibration and radiometric correction
- limited penetration
- spectral confusion
- cost and accessibility
- ethical and privacy concerns
Passive Sensors (3) and the Idea of It - Answer -- Multispectral
- Hyperspectral
- Thermal
received energy from sun or Earth, emitted energy may be heat
Active Sensors (2) and the Idea of It - Answer -- Lidar
- Radar
Sensor provides energy
Name the 4 Times of Resolution - Answer -- spatial
- spectral
, - temporal
- radiometric
Spatial Resolution - Answer -pixel size
Spectral Resolution - Answer -width of each spectral band
- Full Width at Half Maximum (FWHM)
Temporal Resolution - Answer -repeat time to image location (how frequently)
Radiometric Resolution - Answer -radiance range of each digital number
Nominal spatial resolution is defined as the... - Answer -dimension (D) in meters of the
ground projected IFOV
Most RD systems use optics with... - Answer -constant IFOV (beta)
Name 3 ways that spatial resolution can be improved - Answer -- sensor design
improvements
- fly closer to the ground (smaller area)
- reduce the angular field of view
Spatial/Spectral/Temporal Tradeoff - Answer -look at slides
Fine/high spatial resolution = ____________ IFOV - Answer -small
Small IFOV = ____________ in energy detected = _____________ radiometric
resolution - Answer -reduction, less
To increase the radiometric resolution without reducing spatial resolution what should
you do? - Answer -decrease the spectral resolution
Reduce the spatial resolution (making it bigger - more area) improves... - Answer -
radiometric and/or spectral resolution
Name the 2 models of EMR - Answer -- the wave model
- the particle model
EMR was conceptualize as an electromagnetic (EM) wave by... - Answer -Jame Clerk
Maxwell in the 1860s
Wave travels through space at speed of light, c, which is... - Answer -3 x 10^8 m/s or
300,000 km/s
EM waves consist of what 2 fluctuating fields? - Answer -- electric
- magnetic
Remote Sensing - Answer -art, science and technology of obtaining reliable information
about physical objects and the environment, through the process of recording,
measuring and interpreting imagery and digital representation of energy patterns
derived from non-contact sensor systems
A RS instrument... - Answer -collects information about an object/phenomenon within
the instantaneous-field-of-view (IFOV) of the sensor system without being in direct
physical contact with it
IFOV - Answer -Instantaneous field of view
- angular size of ground area covered by single detector or pixel on sensor
Ground-projected IFOV is area on Earth's surface... - Answer -represented by a single
pixel in an image (essentially ground-sampling distance)
Remote sensing collections information about an ____________ or ____________ -
Answer -object, area
Object - Answer -e.g. the height of a tree crown
Area - Answer -e.g. geographic extent of a lake
RS Measurement are based on: - Answer -Electromagnetic Radiation
EM Spectrum is divided into... - Answer -regions based on how energy acts differently
when it interacts with features
EMR is either... (3) - Answer -- reflected
- emitted
- back-scattered
- depends on what type of radiation we are dealing with (everything on Earth's surface
interacts differently)
Name 6 Reasons for Use of Remote Sensing Data - Answer -- source of spatial and
temporal information
- monitor and develop understanding of environment
- timely information, consistent and cover large area
- availability of historical data
- quantitative applications (temp, gases, surface)
- commercial applications (weather, agriculture, management)
,Remote sensing information may be useful for modelling... (8) - Answer -- global
carbon cycle
- biology and biochemistry of ecosystems
- aspects of the global water and energy cycle
- climate variability and prediction
- atmospheric chemistry
- characteristics of the solid Earth
- population estimation
- monitoring land-use change and natural hazards
Name 10 advantages of remote sensing - Answer -- wide area coverage: potentially
large/inaccessible areas
- global and regional studies possible
- frequent and consistent data collection
- objective and reproducible
- multi-spectral and multi-temporal
- non-invasive and non-destructive
- cost-effectiveness to end users
- data integration and analysis
- rapid response to disasters
- enables operational efficiency
Name 11 limitations of remote sensing - Answer -- often oversold, doesn't provide all
the info needed to conduct research (not replacement for fieldwork)
- not direct, measures surrogate variables
- scale and context
- sensor design limitations
- atmospheric interference
- cloud cover and weather
- calibration and radiometric correction
- limited penetration
- spectral confusion
- cost and accessibility
- ethical and privacy concerns
Passive Sensors (3) and the Idea of It - Answer -- Multispectral
- Hyperspectral
- Thermal
received energy from sun or Earth, emitted energy may be heat
Active Sensors (2) and the Idea of It - Answer -- Lidar
- Radar
Sensor provides energy
Name the 4 Times of Resolution - Answer -- spatial
- spectral
, - temporal
- radiometric
Spatial Resolution - Answer -pixel size
Spectral Resolution - Answer -width of each spectral band
- Full Width at Half Maximum (FWHM)
Temporal Resolution - Answer -repeat time to image location (how frequently)
Radiometric Resolution - Answer -radiance range of each digital number
Nominal spatial resolution is defined as the... - Answer -dimension (D) in meters of the
ground projected IFOV
Most RD systems use optics with... - Answer -constant IFOV (beta)
Name 3 ways that spatial resolution can be improved - Answer -- sensor design
improvements
- fly closer to the ground (smaller area)
- reduce the angular field of view
Spatial/Spectral/Temporal Tradeoff - Answer -look at slides
Fine/high spatial resolution = ____________ IFOV - Answer -small
Small IFOV = ____________ in energy detected = _____________ radiometric
resolution - Answer -reduction, less
To increase the radiometric resolution without reducing spatial resolution what should
you do? - Answer -decrease the spectral resolution
Reduce the spatial resolution (making it bigger - more area) improves... - Answer -
radiometric and/or spectral resolution
Name the 2 models of EMR - Answer -- the wave model
- the particle model
EMR was conceptualize as an electromagnetic (EM) wave by... - Answer -Jame Clerk
Maxwell in the 1860s
Wave travels through space at speed of light, c, which is... - Answer -3 x 10^8 m/s or
300,000 km/s
EM waves consist of what 2 fluctuating fields? - Answer -- electric
- magnetic
