Map Reading and
Interpretation
Latitude and Longitude
Purpose
Locational reference system

The grid system (meridians and parallels) that
surrounds the earth is used for locating places
Each grid line is identified with a number
The intersection between the meridian number
and the parallel number identifies a place’s
location

There is an infinite number of parallels and meridians
Parallels and meridians always intersect at right
angles
Latitude / Longitude
Parallels / Latitude
Parallels = Latitude
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Imaginary lines that run east and west on a map.
Parallels represent degrees of latitude, or how far a
place is away from the equator.
Equator = 0o latitude
North pole = 90o north latitude
South pole = 90o south latitude
Remember:
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Minimum latitude is 0o
Maximum latitude is 90o
Parallels / Latitude
Latitude of a location is the particular
distance (north or south) of the location
from the equator
Measurements

At the equator
the length of 1o latitude means 110.6 km

At the poles
The length of 1o latitude means 111.7 km
For simplicity:

The length of 1o latitude will equal 111 km
Latitude
Meridians / Longitude
Meridians = Longitude
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Imaginary lines that run north and south on a
map from pole to pole. Meridians express
degrees of longitude, or how far a place is
away from the prime meridian.
Prime Meridian = 0o longitude
Runs through Greenwich, England

International Date Line = 180o longitude
Remember:


Minimum longitude is 0o
Maximum longitude is 180o
Meridians / Longitude
Longitude of a location is the particular
distance (east or west) of the location from
the prime meridian
Measurements

At the equator
the length of 1o longitude is approximately 111 km

At 60 north and south of the equator
The length of 1o longitude is 55.5 km
Longitude
Reading Latitude / Longitude
Writing coordinates

Intersecting Coordinates / Unique point where lines
cross:
Latitude always comes before longitude
Add the direction
Example:
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
Latitude / Longitude coordinates: 30oN30oE
Points between degrees
Degrees are subdivided into minutes
60 minutes in each degree / 60 seconds per minute
Example: 20o30’30”N 35o30’30”W
60oN
30oE
Practice
Answers to Practice Map
Sheet 3: Activity 1
A
B
C
D
E
F
G
H
I
J
20oS 100oE
80oN 0o
0o 140oW
60oS 40o W
40oN 60oE
20oS 20oE
40oN 100oW
20oN 40oE
50oN 120oE
10oS 40oW
Use a world map to find latitude and longitude of
the following cities to nearest full degree. Then
in brackets put the minutes.
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Washington
London
Moscow
Tokyo
Vancouver
Ottawa
Answers to
Sheet 3: Activity 2
Use a world map to find latitude and longitude
of the following cities to nearest full degree.
(Brackets represent degrees and minutes)
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Washington - 39°N 77°W
London - 52°N 0°
Moscow - 56°N 38°E
Tokyo - 36°N 140°E
Vancouver - 49°N 123°W
Ottawa - 45°N 76°W
(38°55'N 77°00'W)
(51°30'N 0°10'W)
(55°45'N 37°42'E)
(35°40'N 139°45'E)
(49°13'N 123°06'W)
(45°24'N 75°38'W)
Precision with Latitude / Longitude
Reading Latitude / Longitude
30o 15’ 9”
Seconds
Degrees
Minutes
It may also show
30 15 9 N
Expressing Degree
Degrees may be expressed as:
Coordinate: 65o 32’ 15”
or
Decimal: 65.5375
or
Degrees and decimal minutes: 65o 32.25’
or
Degrees, minutes and decimal seconds: 65o 32’ 15.275”
Conversion
Degrees:Minutes:Second to Degrees
65o45’36” S
(S65:45:36)
65 degrees
+ (45 min x 1 degree/60 min)
+ (36 sec x 1 degree/60 sec x 1 degree / 60 min)
= 65.76 South latitude
Reading Topographic Maps
A more precise location can be identified
using your knowledge of latitude and
longitude measurements of degrees,
minutes and seconds
Topographic Point Locations
Point A: 40o 30’ N 118oW
Point B: 40o 25’ N 117o 55W
Point C: 40o 20’ N 117o 50’W
Point D: 40o 27’ 30” N 117o 47’ 30” W
Point E: 40o 16’ N 117o 52’ 30”W
Activity: Sheet 3B
On the topographic map provided,
estimate the coordinates of the following
locations (use the first letter of the name).
Use the greatest precision possible.
Answers: Sheet 3B
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Brewer Mills
Morehouse Corner
Zealand
Keswick Ridge
MacLean Settlement
Lower Stone Ridge
Pughs Crossing
Sisson Settlement
Tripp Settlement
Keswick
46o 04’ 30”N
46o 04’ 10”N
46o 03’ 10”N
46o 01’ 15”N
46o 04’ 20”N
46o 04’ 10”N
46o 03’ 10”N
46o 02’ 40”N
46o 01’ 10”N
46o 00’ 10”N
66o 59’ 59”W
66o 58’ 30”W
66o 56’ 15”W
66o 54’ 45”W
66o 50’ 50”W
66o 54’ 55”W
66o 51’ 00”W
66o 51’ 50”W
66o 54’ 05”W
66o 49’ 40”W
Riddle
An explorer walked one mile south, one
mile east, one mile north and came back
to the original point. Where did this
happen?
North Pole