1. Section 2 Maps, Charts and Coordinate Systems Continued

2. Universal Transverse Mercator
Is a rectangular grid “overlaid” on the latitude and longitude coordinate system
The earth is divided into 60 UTM zones from west to east
Sixty zones allow the earth to be projected onto maps with minimal distortion.
There are 20 latitude bands from 80° south to 84° north
UTM uses false values (easting and northing) to eliminate negative values
Coordinates are expressed in meters measured from the Equator and a central meridian in each zone

3. UTM Zones - Side by Side
840 N 60 60 60 60 60 60
Equator
800 S

4. UTM Zone Grid Overlay Meridian Central 6º of Longitude 500,000m E
A rectangular grid
measured in meters
is “overlaid” on each
UTM zone.
The grid does not
follow the curved
lines of longitude.
Distances are
measured relative
to the central meridian
of each zone and the
Equator.
Meridian
Central
6º of Longitude
500,000m E

5. Anatomy of a UTM Zone 840 N 60 800 S increasing central meridian
m N
Equator
m N
m E
decreasing
800 S
decreasing
increasing

6. UTM Coordinates
m N
increasing
m N
Equator
decreasing
840 N
800 S
N E
Similar coordinates, but two different locations -
the band letter is needed

7. 60 Zones, and 20 Latitude Bands
UTM Grid Overlay
60 Zones, and 20 Latitude Bands
Zones 1 21 60 G M W X
80º S
84º N D C E F H J K L N P Q R S T U V
Latitude Bands
21 T

8. UTM Zones
You are
here

9. o
108 E o
105 E o
102 E
40° N T N S
512 km
500000E
243000E
756000E
13S
890 km
In this zone, the Northing
will always be 7 integers
long and the Easting
will be 6 integers. Most
GPS readouts preface the
Easting with a 0 for
uniformity.
500000E
230000E
770000E
555 km S N R
674 km
12 13
13 14
32° N

10. 2979 8583 13S 03 42 3 6 UTM Coordinates 10,000 meter digit
Position is given as the distance in meters
relative to the central meridian and Equator.
2979
8583
100,000 meter digit
10,000 meter digit
13S 03 42 3 6
1,000 meter digit
100 meter digit
10 meter digit
1 meter digit
1,000,000 meter
digit
UTM zone
Latitude
band
Easting
Northing

11. Short UTM Location
13S E
The numbers in the
orange boxes are the
small numbers on
the map. The leading
zero is not shown on
the map. N
The number in the blue box is the number found using
the UTM grid overlay.
These are the large
numbers on the map.
Ignore the zone and the light colored digits.
The middle two digits are from the map.
The digit in the blue box is from the UTM overlay.
The short UTM location is
Location is given right (easting) and up (northing).
When using the long or short method, the number
of digits in the easting and northing should be the same.

12. Using the UTM Grid Overlay
The UTM grids on the map are 1000 meters on each side.
Use the UTM overlay
to estimate location
within them.

13. Using the UTM Grid Overlay 1 2 3 4 5 6 7 8 9
End of the building is located at
(short version)

14. Using the UTM Grid Overlay
End of the building is located at
(short version) 9 8 7 6 5 4 3 2 1

15. CBSAR Map Reading Tools
The Team Leader Box found under the table in the cache (taken on all missions) contains plastic overlays to use for UTM calculations.
Please go through the box at the next training to see what’s in there.

16. Projections and Datums
UTM
UTM 1000 meter
grids are true
squares, 1000 m
to a side.
They are the
same size on
all 7 1/2 min.
topos.
Position can be
quickly estimated
by dividing the
grids into tenths.
Projections and Datums
In this diagram the continental United States is represented in two different projections, and un-projected latitude and longitude. This map is depicted using the Clarke 1866 Ellipsoid model for the earth (named after English geodesist A.R. Clarke), which was designated the official ellipsoid model for the U.S. A triangulation station located at Meade Ranch in Kansas was selected in 1927 as the origin for the United States official horizontal datum, based on the Clarke 1866 Ellipsoid model.
Notice that the projections and lat/long are most equal around the Kansas area, closest to Meade Ranch. Kansas, Oklahoma, Nebraska and Missouri are all defined rather equally among the three projections shown in the example. But the farther from Kansas one goes, the greater the distortion among the three projections becomes. This is because distortion in any projection is least when closest to its geographic center.
A datum can be summarized as “the mathematical model for the shape of the earth that gives coordinate system values their earth-tie, or link to the physical world.” In other words, a datum allows a set of coordinates to reference the same feature, whether that feature is represented as a dot on a map, or the knob of a hill on the ground. A datum is a function of a projection. Combined they form a mathematical model of the earth used to calculate the coordinates of a geographic point on any map, chart, or survey system. A datum also forms the reference frame for a selected map coordinate system. Maps are drawn so that every point is a known distance and height from a standard reference point (the datum’s origin). Depending on the datum chosen, one point on the earth can have different sets of coordinates.
Since a datum describes the mathematical model that is used to match the location of physical features on the ground to locations on a map, maps can be drawn so that every point is a known distance and height from a standard reference point (the datum’s point of origin). Different datums may be chosen to represent the same geographic area. Because of this, it’s important for the GPS user to know which datum the coordinates for a location were derived in. Without knowing the correct datum, a GPS navigator may be directed to the wrong location, even though the coordinate values are the same. This is due to what’s known as “datum shift.”
Datum shift means that a single point on a map, or on the ground, will not have the same coordinates between two datums unless those two datums match each other. For example, two commonly used datums in North America are North American Datum 1927 (NAD27) and North American Datum 1983 (NAD83). Between those two datums, the same point on a map or on the ground will have two different sets of coordinates, one set for each of those datums. However, another commonly used datum in GPS is WGS84 (see explanation below), and this datum does resemble NAD83 very closely. For most navigation purposes, NAD83 and WGS84 can be interchanged with little datum shift occurring.
There are several datums currently in use in North America. The most common datum used on U.S. Geological Survey maps is North American Datum 1927, and it has many of its own variations:
NAD27 Caribbean
NAD27 Canada
NAD27 Alaska
NAD27 CONUS (for “continental U.S.”)
NAD27 Cuba
NAD27 Mexico
A GPS receiver will likely include all of these variations of NAD27, so it’s important to pay attention to the GPS receiver’s screen when selecting one of these datums to make sure that the correct one is selected.
The Global Positioning System uses its own unique datum, WGS84, or World Geodetic System Most GPS receivers use this datum by default, which means that data is collected and processed by the GPS receiver using WGS84, but position information is presented to the user in whatever datum is chosen during the GPS receiver’s setup. It’s up to the GPS user to find out what datum and coordinate system (more about that later) data should be collected in prior to commencing a mapping mission.

17. Latitude and Longitude
2.5’ = 2’ 30” (x3)
2.5 minute= 2.5’ = 2’ 30” (x 3)
Grid is narrower at top than bottom
Since there are
(3) 2.5’ grids
in each direction,
these are called
7 1/2 minute
topos or quads
USGS
1:24,000
topographic
map
It is difficult to
quickly determine
or even estimate
position in lat/lon
BUT
aircraft operate
using lat/lon
Projections and Datums
In this diagram the continental United States is represented in two different projections, and un-projected latitude and longitude. This map is depicted using the Clarke 1866 Ellipsoid model for the earth (named after English geodesist A.R. Clarke), which was designated the official ellipsoid model for the U.S. A triangulation station located at Meade Ranch in Kansas was selected in 1927 as the origin for the United States official horizontal datum, based on the Clarke 1866 Ellipsoid model.
Notice that the projections and lat/long are most equal around the Kansas area, closest to Meade Ranch. Kansas, Oklahoma, Nebraska and Missouri are all defined rather equally among the three projections shown in the example. But the farther from Kansas one goes, the greater the distortion among the three projections becomes. This is because distortion in any projection is least when closest to its geographic center.
A datum can be summarized as “the mathematical model for the shape of the earth that gives coordinate system values their earth-tie, or link to the physical world.” In other words, a datum allows a set of coordinates to reference the same feature, whether that feature is represented as a dot on a map, or the knob of a hill on the ground. A datum is a function of a projection. Combined they form a mathematical model of the earth used to calculate the coordinates of a geographic point on any map, chart, or survey system. A datum also forms the reference frame for a selected map coordinate system. Maps are drawn so that every point is a known distance and height from a standard reference point (the datum’s origin). Depending on the datum chosen, one point on the earth can have different sets of coordinates.
Since a datum describes the mathematical model that is used to match the location of physical features on the ground to locations on a map, maps can be drawn so that every point is a known distance and height from a standard reference point (the datum’s point of origin). Different datums may be chosen to represent the same geographic area. Because of this, it’s important for the GPS user to know which datum the coordinates for a location were derived in. Without knowing the correct datum, a GPS navigator may be directed to the wrong location, even though the coordinate values are the same. This is due to what’s known as “datum shift.”
Datum shift means that a single point on a map, or on the ground, will not have the same coordinates between two datums unless those two datums match each other. For example, two commonly used datums in North America are North American Datum 1927 (NAD27) and North American Datum 1983 (NAD83). Between those two datums, the same point on a map or on the ground will have two different sets of coordinates, one set for each of those datums. However, another commonly used datum in GPS is WGS84 (see explanation below), and this datum does resemble NAD83 very closely. For most navigation purposes, NAD83 and WGS84 can be interchanged with little datum shift occurring.
There are several datums currently in use in North America. The most common datum used on U.S. Geological Survey maps is North American Datum 1927, and it has many of its own variations:
NAD27 Caribbean
NAD27 Canada
NAD27 Alaska
NAD27 CONUS (for “continental U.S.”)
NAD27 Cuba
NAD27 Mexico
A GPS receiver will likely include all of these variations of NAD27, so it’s important to pay attention to the GPS receiver’s screen when selecting one of these datums to make sure that the correct one is selected.
The Global Positioning System uses its own unique datum, WGS84, or World Geodetic System Most GPS receivers use this datum by default, which means that data is collected and processed by the GPS receiver using WGS84, but position information is presented to the user in whatever datum is chosen during the GPS receiver’s setup. It’s up to the GPS user to find out what datum and coordinate system (more about that later) data should be collected in prior to commencing a mapping mission.

18. Exercise
Calculate the location or the road intersection as you did in the Lat. & Long. Exercise.
For the first exercise just estimate the location without using a grid (just guess at the location).
Write your answer with just one digit beyond what is provided on the map. (e.g mE)

20. Exercise
On the next slide we have put a 100 meter grid over the same map. This duplicates using a plastic grid over your paper map.
Recalculate the location with the help of the grid.
After doing the exercise, go to the next slide to see the answer.

22. Answer
UTM zone 13S E N

23. Answer down to
1 meter from
Team computer

24. The left point is plotted at 1 M accuracy
The right pt. Is plotted at 100 M accuracy
This should give you confidence that your estimate will put you close enough

25. Topo Maps Contour lines on Topo maps tell us about elevation
Lines close together = steep
Lines far apart = flatter
See how far apart lines are near the lake … lakes are flat
See how close the lines are going up the ridge to Meridian Lake
From Washington Gulch Rd.

26. Elevation 9400 feet 9600 feet (follow from #)
200’ difference in dark brown
4 lighter lines between
Each line is 40’ (200/5 you have to count the dark line also)
Your actual map may be different than the on shown here 1 2

27. Follow the route from Washington Gulch Rd. to the lake
9600
Follow the route from Washington Gulch Rd. to the lake
The route climbs from about 9400’
It climbs past 9600’
The lake is near 9660’

28. start
Compare the elevation profile below with the route up from the road to the lake.
Down to river
start

29. The I.C. has asked you to pick a landing zone for a helicopter.
Which location (A or B) would you chose?
victim B

30. The I.C. has asked you to pick a landing zone for a helicopter.
Which location (A or B) would you chose?
victim B
Answer = B
Much flatter
Don’t have to carry victim up hill
You need to go to B to make sure it really is a good L.Z.

31. Topo Maps
The best way to understand contours is to take a map into the field.
Look at the land around you and compare to the map

32. End of Section 2
Next up:
Compass
G P S