Navigation/Coordinate systems lesson

00:00

3 min

Introduce topic title

Introduce Instructor

Present Objectives

00:03

Distribute maps, pencils, erasers

• safe pencils to use on maps
• safe eraser to use on maps

coordinates systems

A coordinate system is a way of specifying a location on map

3 systems you're likely to use in SAR.

• UTM - Universal Transverse Mercator
• Geographic Coordinate System - Latitude/Longitute
• Legal Land Description - Section, Township. Roads and Approaches

UTM

• SAR uses mostly
• taught in SAR fundamentals

• 3 parts: ZEN
  • Zone
  • Easting
  • Northing

Zones

• Each zone is a grid system that stretches from near the antarctic to the far north
• different strips necessary because laying a square grid on a round world
• Each zone is 6 degrees wide
• Pincher Creek is right at the boundary between zone 11U (on west) and zone 12U (on east)
• Each map shows it's zone

Northing

• how far north of the equator (in meters)
• written on left and right edge of map
• horizontal blue lines have same northing
• every 1000m
• only 2 of the digits are shown for most blue lines

Easting

• relative to the center of the Zone
• center of Zone is 500,000m
• bigger number the further east you go
• smaller number as you fo west
• written on the bottom and top edge of the map
• vertical blue lines have same easting
• sometimes starts over from 99 to 00 (with carry)

Stating a UTM

• order: Z - E - N
• e.g. 12U 710000mE 5477000mN
• find this location: middle of Beauvais Lake

Being more precise

• estimate inside blue square
• using roamer

Short form UTM

• used mainly over radio
• 6 digits (3 easting, 3 northing, no zone)
• assumes they know which map you're using
• accurate to 100m

Geographic Coordinate System

• Latitude and Longitude
• used by aircraft
• Better when dealing with 100's of kilometers
• used by untrained people (all they've heard of)

Degrees

• A circle has 360 degrees.
• World is a sphere. Equator is a circle.
• measure longitude West 180 degrees along the equator from the prime meridian (Greenwich England)
• measure East 180 degrees
• meet at about the International Date Line in the Pacific

• Measure north or south along the longitude to get the latitude
• 90 degrees Latitude North to the north pole
• 90 degrees South to the south pole

Minutes

• Degrees are too big
• Every degree of latitude is 60 nautical miles
  • = 69 miles
  • = 111 km

• On the equator a degree of longitude is also 60 nautical miles
• gets smaller the closer to the poles you get

• Degrees are divided into 60 minutes
• written as '
• 1' of latitude is 1 nautical mile
  • = 1.15 miles
  • = 1.9 km

• 1' of longitude varies depending on how close to the poles

Seconds

Getting even more accurate.

• 60 seconds in a minute
• written as "
• 1" of latitude is 101 feet
• = 31m

Full Lat/Long

• example: 49deg 23' 24" N, 114deg 20' 25" W

Reading on a map

• latitude goes from bottom to top along edges of map
• each minute is marked by a black or white bar
• seconds have to be estimated

• longitude goes from right to left along top and bottom edge of map
• size of minute is different

• no lines join opposite sides of map
• gray lines (township and section) are sometimes close
• roll edge of map to create temporary straight line
• read degrees and minutes, estimate seconds

Exercise

find lat/long of several features

Convert by GPS

• create waypoint in one coordinate sytem
• display in another

• need to match Map Datum used on map