What is Remote sensing?
The science of acquiring data about earths surface without being in contact with it
How is RS done?
sensing and recording reflected or emitted energy and processing, analyzing and applying that information.
Basic principle of RS
Electromagnetic radiation- remote sensors measure radiation
Advantages to RS
- No physical contact: min cost ->max safety
- Synoptic: covers large area
- Unobtrusive: remote areas
- Systematic: predictable, repeatable, continuous
- Global coverage
- Accurate: reliable repeatable data
Disadvantages to RS
- Accuracy: resolution, distance, not phsyically there
- Expensive
- Prone to interference (clouds, storms, time of day)
- Indirect measurement of light (derived variables- reflection)
- Data is interpreted: pixels can be interpreted differently
What to consider when choosing a sensor platform?
- cost to operate
- desired spatial coverage
- spatial resolution
- desired temporal resolution
What is remote sensing process? (6 levels)
- Energy source or illumination (Electromagnetic radiation)
- Radiation comes in contact with the Atmosphere (interact/interfere)
- Interaction with target; energy passes through atmosphere
- Energy is recorded by sesnor: energy has been scattered or emitted from target: sensor collect & records
- Transmission, Reception, and Processing of data
- Interpretation & Analysis: processed image is interpreted (visually or digitally) to extract information about the target
- Application: apply information from imagery of target
What is the visible light spectrum (nm)
400nm -800nm
What is a passive sensor
Sensors that detect naturally emitted radiation by an object, area, or phenomenon
- Reflected Solar Radiation (EMR)
- Emitted Thermal energy (Heat)
What is an active sensor
energy directed at an object by the sensor which is then reflected/ scattered
- backscattered radiation
Why is RS critical in Earth Observation
collection of measurements over large surfaces, change analysis
Uses of RS in Earth Observations
- Location
- Topography
- Vegetation Variables
- Surface temperatures
- Geology
- Atmosphere (weather)
- Water (bathymetry)
- Snow & Ice (Glaciers)
- Volcanism
- Land use/ land cover
