locating positions on earth
DESCRIPTION
Locating Positions on Earth. Coordinate Systems. Earth scientists use the latitude-longitude coordinate system to identify locations on Earth’s surface. Latitudes and longitudes are measured in degrees (°) and minutes (‘). Each degree (°) is made up of 60 minutes (‘). - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/1.jpg)
Locating Positions on Earth
![Page 2: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/2.jpg)
Coordinate Systems
Earth scientists use the latitude-longitude
coordinate system to identify locations on Earth’s
surface. Latitudes and longitudes are measured in degrees (°) and minutes (‘). Each degree (°) is made up
of 60 minutes (‘). Sydney, Australia = 34°0’S, 151°0’E
![Page 3: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/3.jpg)
Latitude
The equator (0°) marks the middle of the Earth –halfway between the North and South poles.
![Page 4: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/4.jpg)
LatitudeThe latitude of any point on the Earth
is the angular measurement between the
location and the equator using the center of the Earth
as a focal point.
Latitude measurements above the equator are referenced with an “N”
for Northern Hemisphere.
Latitude measurements below the equator are referenced with an “S”
for Southern Hemisphere.
![Page 5: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/5.jpg)
Measuring Latitude
Scientists may use the position of stars in the night sky to determine the latitude of their position on the Earth’s surface.
Polaris (The North Star) is seen by observers in the Northern Hemisphere. The star is positioned in the night sky
nearly directly over the North Pole.
![Page 6: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/6.jpg)
Measuring Latitude
Pointer stars in the “Big Dipper” constellation allow the viewer to find Polaris .
A sextant is an instrument used by an observer to determine the angle
between Polaris and the horizon.
observer
Polaris
horizon
![Page 7: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/7.jpg)
Longitude
The prime meridian (0°) marks the middle of the Earth –halfway between
the Eastern and Western Hemispheres.
![Page 8: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/8.jpg)
LongitudeThe meridian that
passes through Greenwich, England
has been designated as the prime meridian (0°).
The longitude of any location on the Earth’s
surface is the number of degrees between the
location and that of the prime meridian.
Longitudes increase east and west from the prime
meridian to the International Date Line (180°)
Longitude measurements
east of the prime meridian are
referenced with an “E” for Eastern
Hemisphere.
Longitude measurements
west of the prime meridian are referenced with a “W” for
Western Hemisphere.
Eastern Hemisphere
Western Hemisphere
![Page 9: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/9.jpg)
Measuring Longitude
The longitude of a position on Earth’s surface can be determined if one studies the rate of Earth’s rotation
over time.
![Page 10: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/10.jpg)
Measuring Longitude
Scientists will use GMT = Greenwich Mean Time as a means by which to gauge the
local time and location of longitude for an
observer.
For example, if the sun has reached its
highest altitude in the sky (local noon – 12 pm) at Greenwich, it will be 11am at 15° E
and 1pm 15°W.
0°12 pm
15°E1 pm
15°W11 am
Remember*** The Earth rotates from
west to east at a rate of 15° per hour.
![Page 11: Locating Positions on Earth](https://reader035.vdocuments.mx/reader035/viewer/2022081507/56816103550346895dd0471a/html5/thumbnails/11.jpg)
Measuring Longitude – Sample Problem “If it 6 pm at Greenwich England, at
which location would it be 10 pm?”
B
CA
D