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6. Place corner of roamer scale "0" at the 'X', with scale increasing left and down
· Make sure roamer scale is parallel to the UTM grid lines.
5
99
47
91
47
90
5
000m
99
E
7. Count from the
'X'
to the nearest left easting line – 100, 200, ... 500, 600 and 650 m.
8. Add 650 meters to the nearest left easting line.
5
000m
5
650m
· 650 m E +
99
E =
99
E
9. Count from the
'X'
to the nearest northing line, below – 100, 200, ...600 and 700 m.
10. Add 700 m to the nearest northing line below the 'X'.
· 700 m N +
47
90
000m
N =
47
90
700m
N
The final UTM coordinate is:
5
650m
47
700m
99
E,
90
N (zone 11, NAD-27)
The 1:24,000 roamer scale, in the illustration above, has 50 meter resolution (50 meters
between marks), where the 1:24,000 roamer scale on the Eclipse
ence card 6 provide 20 meter resolution (20 meters between marks).
The grid markings change with respect to the scales. So, identify the grid values and grid reso-
lution, when using a map and a UTM grid scale other than 1:24,000.
With UTM grid, it is possible to identify a position with better than 100 meter accuracy, without a
scale. After identifying tick marks around the map's margin, and drawing the grid lines, simply
estimate the distance from the lower left-hand corner of the square grid that surrounds the 'X'.
Remember, eastings always increase to the right, and northings always increase up.
10.2 Latitude And Longitude Coordinate System
Latitude and longitude scales are not provided with the Eclipse 8099, but determining a position
using a latitude and longitude scale, or a ruler is an essential navigation skill.
Latitude and longitude is a spherical coordinate system measured from the Earth's center point
6
6
00
01
47
91
47
000m
90
N
6
00
6
01
Figure 29
8099 base and quick refer-
16
to locations on its surface. A position on Earth is measured in degrees ( ° ), minutes ( ' ) and
(figure 29 ).
seconds ( " ), where 60 seconds = 1 minute & 60 minutes
= 1 degree. Very similar to time on a clock. Measurements
begin at the Equator (0° latitude) and the Prime Meridian
(0° longitude).
In figure 30, the position is read:
45° 00' 00" N. Lat. = 45 degrees, 0 minutes and 0
seconds north latitude
60° 00' 00" W. Long. = 60 degrees, 0 minutes and 0
seconds west longitude.
o
108
30'
o
43
07' 30"
5'
2' 30"
o
43
00'
o
108
30'
10.2.b -- Map Preparation
1. Identify the tick marks, and draw lines
connecting the tick marks (figure 32).
· The lines will produce 9 rectangles.
2. Identify and mark a position on the
map with an 'X'.
3. Use a 1:24,000 latitude-longitude
scale to determine the coordinate
position of the
the Eclipse 8099)**.
** Contact Brunton to purchase a latitude-
longitude template.
o
108
22' 30"
10.2.a -- Latitude and Longitude
o
43
07' 30"
Coordinate From a Topo-Map
27'30"
25'
All 7.5 minute USGS topo-maps are
bound by 7.5 minutes of latitude and 7.5
minutes of longitude. The four corners
5'
of the map are identified by coordinates
in latitude and longitude. In addition, tick
marks are placed every 2' 30" around
2' 30"
the margin of the map, with crosses in
the middle. The 4 crosses identify the
intersections of the 2' 30" tick marks
27' 30"
25'
(figure 31).
o
43
00'
o
108
22' 30"
Figure 31
108
o
43
07' 30"
'X'
(not available with
o
43
00'
108
17
o
45
00' 00" N. Latitude
60
o
00' 00" W. Longitude
o
60
N
o
40
20
o
Latitude
o
45
N.
Increase
60
o
W.
0
o
o
80
o
20
60
o
40
o
E
S
W
Longitude
Increase
Figure 30
o
o
30'
108
22' 30"
o
43
07' 30"
o
43
00'
o
o
30'
108
22' 30"
Figure 32
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