Unit: Remote Sensing/ Topography Flashcards
What is remote sensing?
Process of gathering data about Earth using instruments mounted on satellites, airplanes, or ships
What are the five types of Remote sensing?
Landsat, Topex, Poseidon, sea bean, GPS, GIS
What does Radar stand for?
Radio and detection and ranging
What does sonar stand for?
Sound of navigation and ranging
What type of waves do radar use
They are electromagnetic waves because they are diminished in water, mainly used for atmospheric and ground observations
What type of waves do Sonar use?
Acoustic because it travels easily through water- used for navigation and measurements under water
What do landsat satellites do?
They record reflected wavelengths of energy from Earth’s surface. These include wavelengths of visible and infrared radiation
How does landsat satellite work??
It is equipped with a moving mirror that scans the surface. The mirror has rows of detectors that measure the intensity of energy received from Earth
What is Topex Poseidon? What does it stand for?
Is a satellite designed to measure ocean surface topography with accuracy… Stands for topographic experiment
How does Topex Poseidon Work?
Uses radar high frequency signals that are transmitted from the satellite to the surface of the ocean, a receiving device and pick up the returning echo as it is reflected off the water
What is Sea Beam?
Used to map the ocean floor used on a ship and not a satellite
How does sea beam work?
A sound wave is sent from a ship toward the ocean floor a receiving device and picks up the returning echo. When it bounces off the ocean floor computers on the ship. Calculate the distance from the ship to the ocean floor using the speed of sound in the water
What is GPS stand for
Global positioning system
What is GPS
Is a satellite navigation system that allows users to locate their approximate position on Earth. They’re about 30 satellites orbiting the earth for use
What are uses for GPS?
Navigation for airplanes and ships, Detecting earthquakes create maps and track wildlife, Locate lost people and find program destinations
What is GIS?
Geographic information system
How does GIS work?
Uses a database of information gathered by scientists, professionals and students to create layers or themes of information that makes a comprehensive map
What are uses of gis?
Scientists use GIS technology for tracking volcano, mapping to track pollution
What are 4 important rules to reading topographic map?
- The closer the lines, the steeper the slope
- Contour line spend when they cross a river
- Contour lines form closed loops are extend to the edge of a map
- Sometimes lines are drawn with small marks or hatcher’s pointing inward
What do closer lines indicate
that the elevation is changing Quickly!
What does closer lines mean?
The close of the lines are together the greater the change in elevation
What happens when contour lines cross a river?
They bend upstream+ the point is always upstream)
How can you find elevation on map?
The highest elevation of a hill you can find can be calculated by the last or highest contour line
What are lines with small lines?
Represent a depression or hole ( called hacthers)
What is formula for gradient?
Change in elevation over distance
What is a field map?
Map that shows the elevation of specific points in an area
what is a map?
diagram or representation of and area of land or water that shows the physical features of an area
cartography
science of making maps
How do we describe location on Earth?
use a coordinate system
coordinate uses 2 numbers
- north/south
- east/ west
latitude
coordinate specifies east/west
how do latitude lines run
horizontally
center of earth latitude
equator 0 degrees
equator splits what?
earth in to 2 halves= Northern/ Southern hemispheres
what is highest northern latitude
90 N degress corresponds to north pole
what is highest southern latitude?
90 S degrees corresponds with southern pole
where is tropic of cancer?
23.5 N degrees
where is Tropic of Capricorn?
23.5 S degrees
where does the prime meridian run through?
Greenwich, England
Where is the international dateline?
exactly opposite of where the prime meridian is
what is the international dateline?
where day begins/ends
what is celestial navigation
use of stars to navigate
Where is polaris?
located directly above north pole; this is a stagnant (90 N)
What is altitude of a star
is the angle of the star above the horizon
What is zenith?
term used to describe highest point in the sky (is the point directly above you)
where can you see polaris?
only in northern hemisphere- is at north pole
what are the 5 types of projections
Mercator, conic, topographic, geologic, gnomonic
what is a mercator projection?
parallel lines of latitude and longitude
How is it used?
navigation of ships and planes
what are the distortions
land near poles is distorted
What is a conic projection?
made by points and lines from a globe onto a cone where the cone touches the globe at a particular point
what are conic projections used for ?
used for road and weather maps
Where on conic projections distorted?
the top and bottom are dstorted
what are gnomonic projections?
projecting points and lines from a globe onto a piece of paper that touches the globe at a single point.
What are gnomonic projections used for?
Great circle routes
Where is gnomonic projections distorted?
direction/ distance between landmasses
What are Geologic maps?
projections that show the type of rocks below the surface in a given area
What are geologic maps’ distortions?
depends on type used
What are topographic maps?
shows elevation and changes of land in the area
How are Topographic maps distorted?
depends on type used
What are contour lines?
lines on topographic maps used to show change in elevation; drawn in intervals
What is a topographic profile?
picture of what the land would look like from the side, it is a cross section of the land
What is a map legend?
explains symbols on the map
what is the map scale?
the ratio between distances on a map and actual distances on the surface of Earth
What are the 3 types of map scales?
fractional, verbal, graphic
verbal scale?
expresses distance as a statement
graphic scale?
a line that represents a certain distance
fractional scale
expresses distance as a ratio