1. GEOREFERENCING SYSTEMS
OUTLINE:
description of georeferencing systems
cartesian/plane coordinates
global systems
local systems

2. GEOREFERENCING SYSTEMS
method for representing/identifying locations on earth’s surface
purposes:
location of a specific map feature may be measured and recorded for future use
known coordinates of a feature may be used to find and map its location
number of different systems based on variety of datums, units, projections and reference systems

3. TYPES IN USE Plane/Rectangular Coordinates
used for locating points on a flat map
cartesian coordinates and modern form
Geographical Coordinates
primary system
used for locating positions on uniformly curved surface

4. CARTESIAN SYSTEMS
mathematical coordinate system defined by distance away from origin
locate an origin
set two axes through origin in fixed directions, at right angles to each other
x is horizontal axis (east) and y is vertical axis (north)

5. CARTESIAN SYSTEMS

6. CARTESIAN SYSTEMS
calculate distance between locations

7. CARTESIAN SYSTEMS Advantages based on simple mathematics Disadvantages
coordinates tied to that particular projection and spatial extent

8. GLOBAL SYSTEMS Latitude and Longitude angular measurements
expressed as decimal degrees or degrees/minutes/seconds
global coverage

9. LATITUDE AND LONGITUDE
prime meridian and equator are reference planes used to define longitude or latitude (divide earth into two spheres

10. LATITUDE AND LONGITUDE
latitude: angular measurement of a place expressed in degrees north or south of the equator

11. LATITUDE AND LONGITUDE
parallel: line connecting all points along the same latitudinal angle (name of the line).
run from 0o at equator to 90o N/S at poles in an east-west direction

12. LATITUDE AND LONGITUDE
distance between parallels does not change significantly
one degree of latitude = ~111 km; one minute = 1.6 km; one second = 30 m

13. LATITUDE AND LONGITUDE
longitude: angular measurement of a place east or west of a reference meridian (Prime Meridian).

14. LATITUDE AND LONGITUDE
meridian: line connecting all points along the same longitude.
run in N-S direction from pole to pole; from 0o to 180o E/W

15. LATITUDE AND LONGITUDE
meridians converge at poles
longitude varies from 111 km (equator) to 0 (poles)

16. LATITUDE AND LONGITUDE

17. International Date Line
Prime Meridian

18. LATITUDE AND LONGITUDE
Degrees to Decimal Degrees
example: 45° 33' 22" (45 degrees, 33 minutes, 22 seconds).

19. LATITUDE AND LONGITUDE
Advantages
global coverage (supports small scale maps)
Disadvantages
parallels are not really equally spaced (approx. 1 km difference from pole to equator)
many significant digits are required for high precision mapping

20. GLOBAL SYSTEMS Universal Transverse Mercator (UTM)
based on the transverse Mercator projection, with scale exaggeration increases away from the standard meridian
meter is the basic unit of measurement (instead of degrees).
uses northings and eastings instead of latitude and longitude

21. GLOBAL SYSTEMS Universal Transverse Mercator (UTM)
divided into N-S columns 6o of longitude wide – columns are called zones

22. GLOBAL SYSTEMS Universal Transverse Mercator (UTM)
each column is divided into quadrilaterals of 8o of latitude

23. GLOBAL SYSTEMS
columns numbered 1-60 eastward, rows are assigned letters C to X; each quadrilateral is assigned a number-letter combination

24. GLOBAL SYSTEMS
56o V U
Central Meridian

26. UTM GRID expressed as eastings and northings Northings
measure distance north in meters from zero to 10 million
northings are always positive

27. UTM GRID
southern hemisphere, equator is given “false northing” of 10,000,000 m to avoid (-) Northings.
northern hemisphere – equator is assigned northing values of 0 m North

28. UTM GRID
Eastings
referenced to the center line of the zone known as the central meridian
central meridian for each zone is assigned an easting value of 500,000 m

29. UTM GRID
Eastings
measure distance east in metres from central meridian (false easting)
an easting of zero will never occur, since a 6o wide zone is never more than 674,000 m wide

30. UTM GRID y N. Hemisphere origin is (500,000m, 0) x
S. Hemisphere origin is (500,000m, 10,000,000m)

33. UTM GRID
ex. 14U     629,443E     N
from the left, the first number is the UTM zone (or column), the letter is the row designation
so this location is 626,443 meters left (west) of zone 14's central meridian, and 5,521,654 meters up (north) from the equator.

34. Locating on a UTM Map
Look for zone number and mark it down (important to have this indicated)
Read right to the grid intersection before your place of interest. Then measuring right in meters from intersection will give the complete easting
Do the same in the Y direction.

35. Example:
Drill Hole
Zone E N
Therefore the drill hole is located 3,391,250 m north of the equator

36. Drill hole location with easting of 704250E
Without Zone 13 indicated, this easting would not indicate in which UTM zone the hole is located (in the middle of Pacific or over Africa??)

37. Examples
Hilltop 3726?
Zone E N
Hilltop 3774?
Zone E N

38. UTM GRID Advantages “real” distances (in meters)
excellent for large-scale maps
Disadvantages
distortion above 80o latitude
non-global coverage

39. GLOBAL SYSTEMS Universal Polar Stereographic
special UTM zones used to cover the polar areas (northern hemisphere 84o-90o; southern hemisphere 80o-90o)
each pole divided into half (N pole - Y and Z grids; S pole – A and B grids)
false eastings and northings are given a value of 2,000,000 meters

40. Note grid designation- starts east at 0 longitude 84N/80S towards 180E

41. GLOBAL SYSTEMS World Geographic Reference System (GEOREF)
used for aircraft navigation
based on latitude and longitude
globe is divided into 12 bands of latitude and 24 zones of longitude, each 15o in extent
15-degree areas further divided into one degree units identified by 15 characters

42. GLOBAL SYSTEMS

43. GLOBAL SYSTEMS
15-degree areas further divided into one degree units identified by 15 characters

44. GLOBAL SYSTEMS
two numeric characters designate the integer number of minutes of longitude east of the one degree quadrangle boundary longitude.
two additional numeric characters designate the number of minutes of latitude north of the one degree quadrangle boundary latitude.

45. GLOBAL SYSTEMS
Postal codes
Telephone codes