CTC Navigation Bootcamp 2017 - Module 1 - Positioning and Distance, Latitude & Longitude

Being a navigator is all about reading maps, identifying location and direction, understanding topography & terrain, creating trails and navigation

Welcome to the first module of our 8 part course. All parts are designed as a combination of illustrated theory and practical hands-on so you can grasp the topics taught practically through both online and field assignments.
If you haven't done already, ensure to Register First.

Module 1

Type: home assignment

Requisite: install Google Earth on your laptop

Date: March 27th

Deadline: Friday, Mar 31st

Duration: 1-2 hours

Submit one set of answers per team

All team members to participate

Google Earth

Open Google Earth on your laptop

A 3D view of our planet will be shown

You can move the globe in different directions with your mouse

Goto menu View - Grid

A grid will now be displayed across the globe: horizontal circles (latitude) and vertical circles (longitude)

Each location on our planet is uniquely identified by the intersection of two circles: the longitude and latitude

Longitude

Longitudes connect both poles (North, South) and cut the equator vertically

The equator encircles the Earth 360 degrees (full circle)

The "zero" longitude or "Greenwich Meridian" is the vertical circle which runs through London.

Vertical circles right of the  "Greenwich Meridian" are called Eastern longitudes: most of Europe and Asia (0 to 180 degrees East)

Left are the Western Longitudes: the Americas (0 to 180 degrees)

(move the globe horizontally with your mouse to see all Eastern and Western longitudes)

Latitude

Latitudes are horizontal circles which run in parallel with the Equator

The "zero" latitude corresponds to the Equator

From North to the South pole there are 180 degrees (half circle)

The horizontal circles above the equator till the North pole are called Northern latitudes (0 to 90 degrees)

The ones below the equator till the South pole are called Southern latitudes (0 to 90 degrees)

(move the globe vertically with your mouse to see all Northern and Southern latitudes)

Position

Every location on our planet is uniquely identified by the intersection of one vertical and one horizontal circle

This is called the latitude and longitude of that location

Let's take for example Chennai city

Move the globe with your mouse till you see India and Chennai

Chennai is cut by following two circles:

* Vertical circle (Longitude) 80 degrees right or East from Greenwich Meridian or Prime Meridian

* Horizontal circle (Latitude) approximate 13 degrees above or North of the Equator

So Chennai's location is uniquely identified as Longitude 80 deg East and Latitude 13 deg North 

(Move the globe with your mouse to see Chennai and check the intersecting longitude and latitude)

Degrees, Minutes, Seconds

Degrees are very large: the perimeter of our planet is 40 thousand kilometers (along the Equator)

This corresponds to 360 degrees which means 1 degree is equal to approx 111 kilometers or 60 miles (nautical miles: 1 mile = 1852 meters)

To fix a location more accurately every degree will be divided into 60 minutes: 1 minute = 1 mile

And every minute will be further divided into 60 seconds: 1 second = approx 31 meters

Use your mouse to zoom further into the Global into Chennai: let's find the unique location of the Cricket Stadium near Marina beach

Zoom in until you can see the stadium: it's a white circle right off Marina. 

It's location is nearby the intersection of two lines:

Longitude: 80 deg 16 min 48 seconds East

Latitude: 13 deg 03 min 54 seconds North

You can identify the exact location of the Cricket Stadium by dropping a yellow pin:

Longitude: 80 deg 16 min 45 sec

Latitude: 13 deg 3 min 46 sec North

(Try it yourself)

Distance

Similarly, distance between two locations can be measured in seconds, minutes and degrees

For example let's check the distance between the Cricket Stadium and the Marina Lighthouse

The Cricket stadium is located near latitude North 13 deg 03 min 54 sec

The Lighthouse is near latitude North 13 deg 02 min 24 seconds

Every horizontal latitude line shown in the grid below is 18 seconds or approx. 560 meters (1 sec = 31 meters)

The distance between both is 1 minute and 30 seconds

This corresponds to 1 mile (1 mile = 1852 meters) and 30 seconds (1 sec = 31 meters) or approx 2.782 meters

You can measure the exact distance in Google Earth through the Ruler tool

Click on the Stadium and next click on the Lighthouse

Distances is 2565 meters (less than first approximation above as the Cricket Stadium is actually lower then the N 13 03 54 latitude line)

(Try it yourself)

Assignment #1

Now it's time to for some hands! Go through the practical assignment below to validate your understanding of latitudes and longitudes, the fundamental basis on which navigation will work. Submit your answers (one per team, not individually) through this form

Question 1 - what's the location (longitude, latitude) of the "TIDEL Park"

(Search on name in Google Earth top-left search box)

(Drop a yellow Pin to identify long, lat)

Question 2 - what's the location (longitude, latitude) of the "Central Leather Research Institute"

(Drop a yellow Pin to identify lon, lat)

Question 3 - what's the difference (distance) in longitude (East-West) between both locations in seconds?

Question 4 - what's the corresponding approx. longitudinal distance in meters?

Question 5 - what's the difference (distance) in latitude (North-South) between both locations in seconds?

Question 6 - what's the corresponding approx. latitudinal distance in meters?

Question 7 - what's the direct line distance between both location in meters? 

(Use Google ruler tool)

Question 8 - what's the longitudinal distance between TIDEL Park and the sea?

(Same latitude, intersection with sea)

Question 9 - what's the location (lon, lat) of this intersection with the sea?