Quiz

• The purpose of this class is to develop your ability to do what three things?

 Acquire field data

 Process field data

 Interpret field data

Navigation and Orienteering Purpose of Today’s Lab

• Learn how to: Read topographic maps Adjust your compass according to map declination Calibrate your ‘pace’ Navigate using a GPS and compass. Collect data with a GPS. Retrieve data from a GPS. Display GPS data in a GIS. USGS 7.5 Minute Quad

Map Reading Tips • Scale • Legend • Contour intervals • Magnetic deviation (true north differs from magnetic north • The top of the “V” that forms at the intersection of 2 streams point uphill; the bottom points downhill USGS 7.5 Minute Quad

• What does “7.5 Minutes” mean?

– Latitude & Longitude is measured in Degrees, Minutes, Seconds

– 1○ = 60' = 3600"

111○ 50’ 59” W

41○ 46’ 47” N Decimal Degrees Decimal Degrees USGS 7.5 Minute Quad • USGS Maps come in standardized sizes • What does “7.5 Minutes” mean? – 7.5’ latitude x 7.5’ longitude Why are USGS Quads so useful?

• Available for the entire USA, and many other places • Updated frequently • Consistent! 7.5 minute quads always have a scale of 1:24,000 – 1 inch on map = 24,000 inches (2000 ft) in real life – Useful for estimating distances

Using a compass: Azimuth (or Bearing) Using a compass: Declination Declination Determining your Declination

• Look on your map – Constantly Changing!

• NOAA Website: http://www.ngdc.noaa.gov/g eomag-web/#declination

• Declination for Logan is ~12° East

Adjusting Your Compass for Declination Navigating with Compass

• Example: Walk a bearing at 80○ Orienting a Map

• Positioning the map so that it matches what you see. • Requires a compass corrected for declination

(1) Turn the declination-corrected dial until “N” or “0” is at the index mark. (2) Place the compass with the index mark pointing toward top of map. (3) Turn the map & compass together until needle is boxed. Now North on the map and North on the landscape are the same!

A Brief Introduction to GPS

• Constellation of >30 satellites • Development started in 1973; system fully operational in 1995. • System funded by U.S. taxpayers ($750 million per year). • Operated by the U.S. Air Force • Accurate locations require direct line of sight between the satellite and GPS receiver • Vegetation can block signals

A Brief Introduction to GPS

• How does a mobile GPS unit work? • The mobile unit establishes a connection with at least 4 (of 32) satellites – Radio waves are transmitted + distances are calculated  position on earth is determined

Interference may cause errors and diminish accuracy

How is distance to satellite calculated?

• Velocity * Travel time = Distance

• Velocity = speed of light

• Travel time = delay between when a signal is transmitted by a satellite and received by a receiver

GPS

• Coordinate System (or Position Format) is the method of reporting where you are on a surface. – Lat / Long – Degrees, minutes, seconds or Decimal degrees – UTM (UPS) – There are others…

Example: NAD83 UTM Zone 12N GPS: Datum • The earth is not a perfect sphere • The Map Datum is the method of how we approximate the shape of the earth – Best choice depends on where you are – There are many and we will be using NAD 83 – NAD stands for North American Datum

Image courtesy of ESRI GPS

• Projection: A way to place geographic locations from the globe on a flat map • Projections are chosen to minimize distortion • Our chosen projection: UTM – The units are in meters, which is handy for doing field work! Universal Transverse Mercator

• Your bearings will be in Northing (~latitude) and Easting (~longitude)

• You are moving along a grid, spaced out in meters.

• If you are moving straight East/West, your northing shouldn’t change, and vice-versa

– Useful for transects!

Using a GPS

• Allow a moment for your GPS to contact satellites It will need a clear view of the sky

• Confirm you are using the correct position format and datum.

These should be set to UTM UPS and NAD 83 for our purposes. The spheroid will adjust automatically.

Navigate to a waypoint • Where are you trying to go? • Hit FIND and enter coordinates. – You are the arrow – The pink line dictates the shortest path to your point – Many measurements are calculated using velocity…

In Summary… • Topo maps display lots of useful information – Declination, Elevation, Scale, Datum and Projection • Always check compass declination • Always check Datum and Coordinate System or Position Format on your GPS • NAD 83 UTM locations are represented in meters - In relation to the central meridian of your UTM Zone and the Equator

Today’s Lab:

1. Works in assigned groups

2. Submit individual assignment, Due next TH @ 0900

3. Submit on Canvas as a “Quiz”

4. Each group will check-out one GPS unit, 1 compass, and 1 measuring tape.

Today’s Lab: Four Parts

1. Using topo maps

2. Measuring your pace

3. Using GPS

4. Processing and visualizing GPS data Today’s Lab: Four Parts

1. Using topo maps

Classroom activity

1 map per group

Today’s Lab: Four Parts

2. Measuring your pace

1 pace = 1 stride = 2 steps

You must measure your pace before doing the GPS exercise

Today’s Lab: Four Parts

3. Using GPS Follow the directions in the tutorial Be sure to record your track AND a waypoint at each point you navigate to. Each waypoint must be renamed according to the Point Letter Designation = A, B, , D, E, F Navigate to the points in the order you have been assigned (there are 9 unique orders)

Today’s Lab: Four Parts

4. Processing and visualizing GPS data

After you have navigated to all 6 points, return to the classroom and import your GPS waypoints and track to Earth on your laptop

Follow the tutorial instructions

Importing Data to

• Tools -> GPS -> Import

• Help: https://support.google.com/earth/answer/1185357 ?hl=en&vid=1-635768231960376461-3103913036

• Capturing a track on an Android Phone or I-Phone https://play.google.com/store/apps/details?id=com .google.android.maps.