Transcript Universal Transverse Mercator (UTM)

USING UTM
Steve Allen
KCSARA SAR Academy
April 2010
Objectives
Understanding UTM system
Finding coordinates of a point
Plotting a point
Universal Transverse Mercator (UTM)
Metric units (meters)
 World is split into 60, 6º degree zones
 Seattle area is Zone 10N
 Distorted above North 84º, and South 80º,
not applied above these latitudes.
 Smallest grid unit on USGS 1:24000 maps
is 1 km. May be different on different scale
maps!
 Coordinates get larger going east
(easting) from the zone meridian and
larger going north (northing) from the
equator.
To Describe a Location
Datum
Zone
Northing
Easting
Datums
NAD 27
Most older printed maps (Greentrails,
USGS)
NAD 83 /WGS 84
Coordinates from aircraft
Coordinates from 911 dispatcher
Default new GPS unit “out of the box”
NAD 83 and WGS 84 are virtually the
same for our purposes
Map Datum
United States UTM Zones
State of Washington UTM Zones
Identifying the grid
466
467
5157
(Easting)
5157
Map
5156
5156
(Northing)
466
467
Determining Coordinates: Easting
Determine the easting first:
From the object on map ( ) go
to the bottom (or top) edge of the map
Find the nearest smaller coordinate to the
LEFT (W) of your point
5157
5156
465
466
Determining Coordinates: Easting
4
6
5
0
0
0
Determining Coordinates: Easting
Divide the distance between the coordinate to
the left of your point and the coordinate to the right of
your point into tenths
3 tenths
465
This is hundreds of meters
466
Determining Coordinates: Easting
4
6
5
3
0
0
Determining Coordinates: Northing
From the point on map ( ) look to the left (or
right) edge of the map
Find the nearest coordinate below (S) of your
point
5157
5156
465
466
Determining Coordinates: Northing
5
1
5
6
0
0
0
Determining Coordinates: Northing
Count or estimate the number of tenths from the
coordinate BELOW your point TO the corner.
5157
8 Tenths
5156
This is hundreds of meters
Determining Coordinates: Northing
5
1
5
6
8
0
0
Final Coordinates of
465300E 5165800N
But we can go finer, if we use a template
Template
Must match map scale!
1:24,000 (USGS, 7.5 min, 1 in = 2000 feet)
1:25,000 (USGS, 15 min, 1 cm = 0.25 km)
1:63,360 (USGS, 15 min, 1 in = 1 mile)
1:69,500 (Greentrails, 15 min)
Warning - Photocopied map or map printed
from “Topo” may have an odd scale
Using a Template
Can estimate how far into box on a scale of 1
to 10 to find nearest ten meters.
5165820N
Starting corner:
465000E 5165000N
Template placed
on map at
kilometer grid
corner
465360E
Another Way to Use the Template
 Put the 0 corner of the template on the point.
 Read where the block margin hits the template scales.
465360E
Starting corner:
465000E 5165000N
5165820N
Determining Coordinates
489520E
5315440N
Start here.
489000E, 5315000N
Plotting Points
 Underline the last 3 digits of each coordinate.
 What’s not underlined are the margin
coordinates.
Example: 490120E 5315340N
Use template to determine
position within the kilometer
box.
490120E
5315340N
Start here. 490, 5315
Plotting 490120E 5315340N
Questions?