GUS 0821 Lecture Notes - Lecture 9: Decimal Degrees
9 May 2018
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• Latitude/Longitude
o Latitude/Longitude: these are gridlines (or graticule) lines, determined based on
the rotation of the earth
o Latitude: distance measured north and south of the equator
▪ based on the Equator as a base line
▪ measured in degrees, minutes, and seconds
▪ parallel: a line connecting all points of the same latitude
o Longitude: distance measured east and west from an arbitrary meridian
▪ a meridian is a line of longitude
▪ perpendicular to latitude
▪ an arbitrary meridian - the prime meridian - as 0 degrees
•
o Units of measurement:
o Decimal degrees; for ex– Delhi is located at 28.7041° N, 77.1025° E OR
o Degree, minute, seconds (DMS); ex-- ° ' .” N, ° ' .'' E
• Map Projections
o Map projections flatten out the spherical earth (ex)
o All flat maps distort shape or size or direction: can hold one constant, but not all
three
o On this wesite, you’ll find different types of projetions:
▪ http://projections.mgis.psu.edu/
find more resources at oneclass.com
find more resources at oneclass.com
