what is geographical grid?
Answers
Answer:
Geography 140
Introduction to Physical Geography
Lecture: The Geographic Grid (Introduction)
I. Introduction to the Geographic Grid
A. In order to measure accurately the position of any place on the
surface of the earth, a grid system has been set up. It pinpoints
location by using two coördinates: latitude and longitude.
B. It is purely a human invention, but it is tied to two fixed points
established by earth motions: the poles, or ends of the earth's
rotational axis.
1. Longitude represents east-west location, and it is shown on a map
or globe by a series of north-south running lines that all come
together at the North Pole and at the South Pole and are the widest
apart at the equator -- these lines of longitude are called
"meridians."
Figure 1 -- meridians of longitude
[ globe showing meridians ]
2. Latitude represents north-south location, and it is shown on a map
or globe by a series of east-west running lines that parallel the
equator, which marks the midpoint between the two poles all around
the earth's circumference -- these lines of latitude are called
"parallels."
Figure 2 -- parallels of latitude
[ globe showing parallels ]
3. Be aware of the potential for confusing yourself:
a. Longitude = E/W location, but it is shown by a series of N/S
running lines called meridians.
b. Latitude = N/S location, but it is shown by a series of E/W
running lines called parallels.
4. If you look at Figure 1 more closely, notice that meridians connect
all places on Earth having the same longitude (or E/W location): If
you mark a whole bunch of places having the same longitude with
dots and then connect the dots, you create N/S running lines, or
meridians.
5. Looking at Figure 2 above, notice that parallels connect all places
on Earth having the same latitude (or N/S location): If you mark
several places having the same latitude with a series of dots and
then connect all the dots, you create E/W running lines, or
parallels (that are all "parallel" with the equator).
C. There is an infinite number of these latitude and longitude lines,
because every place on Earth is at the intersection of a particular
parallel and a particular meridian. If you had a lot of time and
needed to "get a life," you could pinpoint the precise
coördinates of every single person reading this lecture or,
indeed, of every single person sitting in, say, the campus cafeterias.
Each of you right now occupies an earth location, and all locations on
Earth can be represented in terms of latitude and longitude
coördinates.
D. Maps and globes, however, generally only show a few selected (and
mathematically convenient) parallels and meridians, e.g., by tens or
fifteens or thirties. Otherwise, a map or globe would be one big mess
of dark ink!
II. Geonerd Bonus: Great and Small Circles
A. The geographic grid is built of intersecting great and small circles
with with half-great circles. Hunh?
1. Definitions:
a. A great circle is created whenever a sphere is divided exactly
in half by a plane (imaginary flat surface) passed right through
its center. The intersection of the plane with the surface of
the sphere is the largest possible circle you could manage to
draw on that sphere's surface.
Figure 3 -- different ways of creating great circles
[ exploded globes showing great circles ]
b. A small circle is any circle produced by planes passing through
a sphere anywhere except through its exact center. It will of
necessity be smaller than a great circle, hence the clever name.
Figure 4 -- a small circle
[ exploded globe showing a small circle ]
2. Relevance to latitude and longitude
a. The equator is a great circle drawn along a latitude of 0°
b. The North Pole and the South Pole are single points at 90° N
or S
c. All other parallels are small circles drawn parallel to the
equator; viewed from above one of the poles, they create a
bull's eye pattern in that hemisphere with the pole at the
center (see Figure 2.
d. All meridians are half-sections of great circles, all of them
coming together at both the North Pole and the South Pole (see
Figure 1.
B. Properties of great circles:
1. They always result when a plane passes through the exact center of
a sphere, regardless of the plane's orientation when it enters the
sphere.
2. A great circle is the largst possible circle that can be drawn on
the surface of a sphere.
3. An infinite number of great circles can be drawn on any sphere.
4. One and only one great circle can be found that
hey mate here is you answer
Answer:
in order to measure accurately the position of any place on the surface of the Earth, a great system has been set up it pin points location by using two coordinates latitude and longitude
hope it helps mark me and as brain list and if you don't understand here is a pic
