UTM Coord. - dist. & brg

UTM Coord. - dist. & brg
- Given 2 UTM coordinates
  - want distance & bearing
  - draw & label a diagram ("box")
  - vertical lines are Eastings
  - horizontal lines are Northings
  - label the 2 points (i.e. "1" and "2" ... or POC and wildlife tree)
  - draw line with arrow for "line of travel"
- Distance (pythagorus theorum)
  - a2 + b2 = c2
  - a = diff in easting
  - b = diff in northing
  - c = "straightline distance"
- Bearing
  - compare "line of travel" to compass rose
  - estimate bearing
  - calculate bearing
    - 1) calc. "internal angle"
      - review of TAN & ArcTAN
        
        TAN
        
        = rise / run = opp. / adj.
        
        gives angle as a RATIO
        
        TAN on calculator converts degrees to ratio (e.g. 45)
        
        ArcTAN
        
        is the inverse of TAN
        
        converts angle as a ratio to degrees (e.g. 1.0)
      - a) pick an angle
      - b) compute opp. / adj. (provides a RATIO)
      - c) use ArcTAN to convert to degrees
    - 2) add/subtract from cardinal bearing
    - 3) compare to estimated bearing ... make sense??
- example A = 410,150mE, 5,455,210mN & B = 410,090mE 5,455,250mN
  - draw the box (difference: E= -60m & N= +40m)
  - pick an angle (off north)
  - ratio = 60/40 = 1.5
  - ArcTAN (1.5) = 56 degrees
  - 360 - 56 = 304 degrees
  - distance = sqrt [ 40^2 + 60^2 ] = 72.1m