SC 120 - Universal Transverse Mercator

UTM

Universal Transverse Mercator

Universal transverse Mercator grid (3)

conspicuous blue lines in all NTS maps
no convergence
true x, y coordinates

____km gird on 1:50 000 maps

1

_____km grid on 1:250 000 maps

10

Uses of UTM grid (3)

pinpoint exact locations
express map locations digitally
calculate distances and areas

UTM transverse cylinder projection (3)

turn the cylinder sideways and shrink it
the UTM cylinder cuts the sphere at A-B and C-D
6degrees longitude of very little distortion

UTM grid set up (6)

Cut out that minimally-distorted 6° strip of map
Rotate the earth 6° and re-project the earth
Cut out that minimally-distorted 6° strip of map…
Repeat 60 times to create 60 zones along longitudinal lines
Each zone is 6 degrees longitude wide
Tape all 60 zones together to make a flat, rectangular version of the earth.

UTM zones in Canada

7 to 22

UTM conventions (3)

origin is at the dateline
always eastward looking (left to right)
measure east, then north

How many UTM zones?

60

Which zone is Vermilion?

12

Latitude sub zones

letters C to X (excluding I and O) are used to identify latitude sub-zones from south to north

what regions are excluded from UTM

polar regions
Universal Polar Stereographic (UPS) projection for polar regions

Which sub zone are we in

U

easting

Zone number uniquely locates the longitudinal range

easting conventions (5)

Convention is to measure and report the Easting first
Use the CM as the origin of longitude in each zone
Give the CM a false easting of 500 000 meters
Using a false easting avoids negative numbers
Easting is the distance from the CM (meters

Northing

Measure and report the Northing second
Read Northing as distance from the equator (meters)

UTM naming

Zone, Easting (m), Northing (m)