Maps, Charts and Coordinate Systems

1. Maps, Charts andCoordinate Systems

2. Maps • A map is a two-dimensional representation of the Earth. • Maps incorporate projections and datums for accuracy. • All maps distort the earth to some extent. • When using a map with a GPS receiver, the datum and coordinate system must match.

3. Map and Chart Scales DeLorme Gazetteer - 1:65,000 to 1:400,000 1” = 1.0 miles to 6.3 miles (Scale varies by state) CBSAR uses this

4. Projecting a Sphere Onto a Plane

5. Types of Projections Cylindrical Projection Conical Projection Plane Projection

6. Types of Projections Accurate Shapes Accurate Sizes Exaggerated Sizes Distorted Shapes

7. Types of Projections

8. Map Projections Meade Ranch (Clarke 1866)

9. Coordinate Systems • All coordinate systems reference some particular set of numbers for the size and shape of the earth (the datum). • Coordinates designate locations within a spatial reference system (datum). • There are two types of global coordinate systems: • Angular Coordinates • Rectangular (Cartesian) Coordinates • Latitude and longitude, and Universal Transverse Mercator are two global coordinate systems used by GPS. • Many other coordinate systems exist worldwide.

10. Latitude & Longitude • A spherical coordinate system that is unprojected. • Angular coordinates are perfectly suited to the spherical surface of the earth. • Coordinates are expressed in degrees, minutes and seconds (and variations of that). • Position coordinates are based on an angular distance from a known reference point. • The intersection of the Prime Meridian and Equator. • Lat/long is the predominant coordinate system used for nautical and aeronautical navigation.

11. Latitude & Longitude Prime Meridian (Longitude) 30º N 10º N 0º 0º 10º S Equator (Latitude) Point of Origin

12. Latitude • Latitude is comprised of parallels, which are circles around the earth paralleling the Equator. • Parallels are designated by their angle north or south of the Equator. • The Equator is 0º latitude, and the North and South Poles are at 90º angles from the Equator. • The linear distance between parallel lines never changes, regardless of their position on earth. • 1 minute of latitude = 1 nautical mile = 6076 feet • 1 degree of latitude = 60 nautical miles = 69 statute miles

13. Parallels of Latitude 10º

14. Parallels of Latitude 20º N 10º N 10º 690 statute miles 0º N 690 statute miles 10º 10º S 10º 690 statute miles Crested Butte is 38oN of the Equator

15. Longitude • Longitude is comprised of meridians that form one-half of a circle. • Meridians are designated by their angle west or east of the Prime Meridian. • The Prime Meridian is designated 0º and extends from the North Pole to the South Pole through Greenwich, England. • Meridians are angled, and do not parallel each other. • The linear distance between one degree of longitude at the Equator is approximately 69 statute miles. • The linear distance between one degree of longitude at the Arctic Circle is about 26 statute miles.

16. Meridians of Longitude 10º

17. Meridians of Longitude 10º 240 mi 10º 460 miles Equator 10º 690 miles 110º W 120º W

18. Determining Latitude & Longitude Prime Meridian 30ºN, 50ºW (0º) 30º N Equator (0º) 50º W

19. Lat/Lon Coordinates hddd0 mm.mmm’: N 43040.93’ X W 1160 17.235’ (40.93’/ 60 =.682160) Degrees Decimal Minutes hddd.ddddd0 : N 43.682160 X W 116.287250 Decimal Degrees Different coordinates representing the same location: hddd0 mm’ ss.s”: N 430 40’ 55.8” X W 1160 17’ 14.1” (55.8”/ 60 =.93’)Degrees Minutes Seconds

20. Exercise • Please do this quick exercise and then go to the next slide to see the answer.

21. 38o 47.000’ Here is an actual map. Write the latitude point for the top of Round Mountain in both decimal and second format on a piece of paper. The answer is on the next slide.

22. N 38o 46.8’ N 38o 46’48”

23. Team Computer • The previous exercise was made on the team computer. • We added grids to make it easier for you. • The normal 2.5 grid map is more difficult to use to estimate positions. • Following is a map similar to those found in the cache.

24. Latitude and Longitude Grid is narrower at top than bottom USGS 1:24,000 topographic map 2.5’ = 2’ 30” (x3) It is difficult to quickly determine or even estimate position in lat/lon BUT aircraft operate using lat/lon Since there are (3) 2.5’ grids in each direction, these are called 7 1/2 minute topos or quads 2.5 minute= 2.5’ = 2’ 30” (x 3)

25. Latitude and Longitude • With computer & software we can add grids to make it easier • We can plot exact locations or eyeball it • Let’s practice • Go to next slide

26. Latitude and Longitude • With computer & software we can add grids to make it easier • We can plot exact locations or eyeball it • Let’s practice Write down the Lat. & Long. of the intersection of the two roads. Only do it to 1/10 of a minute accuracy. e.g. N 38o 53.1’

27. Latitude and Longitude • With computer & software we can add grids to make it easier • We can plot exact locations or eyeball it • Let’s practice Answer N 38o 53.4’ W 106o 58.4’ If you were within .1’ of the above answer, you did great!

28. Latitude and Longitude Grid is narrower at top than bottom USGS 1:24,000 topographic map 2.5’ = 2’ 30” (x3) It is difficult to quickly determine or even estimate position in lat/lon BUT aircraft operate using lat/lon Since there are (3) 2.5’ grids in each direction, these are called 7 1/2 minute topos or quads 2.5 minute= 2.5’ = 2’ 30” (x 3) To use our team maps, you need tools as follows

29. Determining Latitude L A T I T U D E LONGITUDE 7.5 min. scale 1:24,000 17’ 30” Latitude of red square = 44º 16’ 48” 2.5 min 44º 15’ 00” Latitude Lines (Parallels)

30. Determining Longitude L A T I T U D E LONGITUDE 7.5 min. scale 1:24,000 Longitude of red square = 115º 19’ 00” Longitude Lines (Meridians) 2.5 min 115º 17’ 30” 20’

31. End of Lat. & Long. Section Next section will be UTM Universal Transverse Mercator