Geoscience Reference
In-Depth Information
Table 2.1
Measuring the Earth's Polar Circumference
North point (latitude:
decimal degrees
)
a.
North point (longitude:
decimal degrees
)
b.
North point (UTM northing:
meters
)
c.
North point (UTM easting:
meters
)
d.
South point (latitude:
decimal degrees
)
e.
South point (longitude:
decimal degrees
)
f.
South point (UTM northing:
meters
)
g.
South point (UTM easting:
meters
)
h.
Distance in decimal degrees [a-e°]
i.
Distance in meters [c-g
meters
]
j.
Knowing the ratio
Dis
tan
ce in decimal
deg
rees
[ ]
i
Dis
tan
ce in meter
mete
[ ]
j
=
360
°
[
PC
]
rs,
we can solve to find the Earth's polar circumference
k.
([j] meters * 360 )
[i]
°
1
1000
[PC] km
=
*
°
To calculate % error (assuming a true polar circumference of
40,008 km)
l.
| [k] km 40,008 km |
40,008 km
−
[PC] % error
=
* 100
Note:
Do not round off! Please retain a minimum of five places to the right of the decimal point.
the compass on a GPS set to true north or monitor the GPS coordi-
nates to make sure that you are following a true north-south track.
If you are following a true north-south track, the eastings should not
change as you are walking.
4. Take a GPS reading at the north end of your chosen track (Note: If you
can “average” the points and then mark the waypoint, please do so
(and make sure that WAAS (Wide Area Augmentation System) correc-
tion is enabled)). Name the waypoint with a meaningful name so that
you can identify it later. Record the UTM coordinates in Table 2.1.
You can record the latitude and longitude from this stored waypoint
later in the laboratory or you can switch units in the field and gather
a new waypoint in decimal degrees (see step 2 above). Enter the value
for decimal degrees in Table 2.1.
5. Repeat for the south end of your chosen track.
2.3.2 Measuring the Earth's equatorial circumference using
Table 2.2
1. Follow steps 1 and 2 for “Measuring the Earth's Polar Circumference”
above.
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