Lecture 4

Question 1

What is reflected solar radiation?

Answer 1

Passive: sun is a direct source of energy (direct reflection off of an object to sensor)

Question 2

What is emitted radiation

Answer 2

Passive: sun is direct source
energy is absorbed into object and re-radiated towards sensor

Question 3

Backscattered radiation

Answer 3

active: sensor provides own source of illumination

direct reflection of energy from sensor-object-sensor

Question 4

Sun-synchronous Orbit

Answer 4

• collects data when the planet is facing the sun
• temporal factors: how frequently can it collect data?
• has a Near-Polar Orbit

Question 5

Geostationary orbit

Answer 5

usually facing only one hemisphere; satellite rotates differently to the planet
- larger than 1000km out of atmosphere

Question 6

Weather Satellites/ Sensors characteristics

Answer 6

• Usually Geostationary: stays on one hemisphere
  **due to weather changing always

Examples:
GOES: Geostationary Operational Environmental Satellite
- orbit 36,000km
Course spatial resolution to understand weather patterns (large area)

NOAA: advanced high resolution radiometer
- sun-synchronous, near polar orbit (830-870km)
- derive vegetation data or ocean temperature

Question 7

Terrestrial Sensors Characteristics

Answer 7

Passive radiation
- Sun-synchronous with a near polar orbit

Question 8

LANDSAT Series

Answer 8

longest running series of environmental satellites
- sensor: Thematic Mapper (TM)

Question 9

Spectral resolution & Spatial resolution

Answer 9

Good Spectral resolution= course spatial resolution
fine spatial resolution= less spectral range

Due to how much energy reaches the sensor

Question 9

Redundancy in RS

Answer 9

have enough and lot of information= data sets are large, what’s important

Question 9

SPOT

Answer 9

Passive, sun-synchronous
revisit time = 1 day
panchromatic @ 10m-> 1m
expensive= finer spatial resolution
moves from side to side= triangle to collect data at different angles

Question 9

IKONOS

Answer 9

collect publicly available high-resolution @ 1 and 4m
high resolution= qualitative assessment

Question 10

QUICKBIRD

Answer 10

60cm panchromatic has finer spatial resolution
= low spectral resolution

Question 11

WORLDVIEW

Answer 11

46cm panchromatic
8 bands
revisit= 1.1 days, changing its viewing angle
larger data sets= costs more, more storage, more analysis/processing time