Lecture 3 Remote Sensing and GIS Flashcards
A GPS receiver senses signals from at least four satellites—a minimum of ______ satellites for location and ______ to determine accurate time.
3, 1
The acquisition of information about distant objects without having physical contact is ______.
Remote sensing
What was the first type of remote sensing?
Aerial photographs
How does satellite imaging work?
Physical elements of Earth’s surface emit radiant energy in wavelengths that are sensed by satellites other craft and sent to receiving stations on the ground.
How are satellite images created?
A scene is scanned and broken down into pixels (picture elements), each identified by coordinates named lines (horizontal rows) and samples (vertical columns).
______ orbits, typically at an altitude of 35 790 km, are high Earth orbits that effectively match Earth’s rotation speed so that one orbit is completed in about 24 hours.
Geostationary or geosynchronous
True or False: When a satellite orbits the Earth, the lower in altitude, the faster it goes,
True
What are the three satellite orbital paths?
Sun synchronous, polar orbit, geostationary
Ground observation is maximized in ______ orbit because Earth surfaces viewed from the satellite are illuminated by the Sun at a consistent angle.
Sun-synchronous
______ remote-sensing systems record wavelengths of energy radiated from a surface, particularly visible light and infrared.
Passive
Many of the beautiful NASA “Blue Marble” Earth composite images are from the ______ satellite
Suomi
_______ remote-sensing systems direct a beam of energy at a surface and analyze the energy reflected back.
Active
______ is an example of active remote sensing.
Radar
Energy reflected back to a radar receiver for analysis is known as ______.
Backscatter
True or False: Radar images collected in a time series allow scientists to make pixel-by-pixel comparisons to detect Earth movement, such as elevation changes along earthquake faults
True
