Module: GeoSwap

Extended by:
Utilities
Defined in:
lib/geo_swap.rb,
lib/geo_swap/zone.rb,
lib/geo_swap/version.rb,
lib/geo_swap/utm_point.rb

Defined Under Namespace

Modules: Utilities Classes: InputError, UtmPoint, Zone

Constant Summary collapse

VERSION = 
"0.2.1"

Class Method Summary collapse

Methods included from Utilities

degrees_to_radians

Class Method Details

.lat_long_to_utm(lat, long) ⇒ Object 



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# File 'lib/geo_swap.rb', line 9

def lat_long_to_utm(lat, long)
  validate_range(lat, long)
  lat_radians = degrees_to_radians(lat)
  long_radians = degrees_to_radians(long)

  zone = Zone.new(lat, long)
  origin_radians = degrees_to_radians(zone.origin)

  equator_factor = (EQUATORIAL_RADIUS / Math.sqrt(1 - (ECC_SQUARED * (Math.sin(lat_radians) ** 2))))
  squared_lat_tangent = Math.tan(lat_radians) ** 2
  ecc_prime_factor = ECC_PRIME_SQUARED * (Math.cos(lat_radians) ** 2)
  origin_factor = Math.cos(lat_radians) * (long_radians - origin_radians)


  ecc_1 = (1 - ecc(1, 1, 4) - ecc(2, 3, 64) - ecc(3, 5, 256))
  ecc_2 = ecc(1, 3, 8) + ecc(2, 3, 32) + ecc(3, 45, 1024)
  ecc_3 = ecc(2, 15, 256) + ecc(3, 45, 1024)
  ecc_4 = ecc(3, 35, 3072)

  latRad_1 = lat_radians
  latRad_2 = Math.sin(2 * lat_radians)
  latRad_3 = Math.sin(4 * lat_radians)
  latRad_4 = Math.sin(6 * lat_radians)

  northing_factor = EQUATORIAL_RADIUS * (
    ecc_1 * latRad_1 -
    ecc_2 * latRad_2 +
    ecc_3 * latRad_3 -
    ecc_4 * latRad_4
  )

  utm_easting = (MERIDIAN_SCALE * equator_factor * 
    (origin_factor + (1 - squared_lat_tangent + ecc_prime_factor) *
    (origin_factor ** 3) / 6 +
    (5 - 18 * squared_lat_tangent + (squared_lat_tangent ** 2) + 72 * ecc_prime_factor - 58 * ECC_PRIME_SQUARED) *
    (origin_factor ** 5) / 120) + EASTING_OFFSET)

  utm_northing = (
    MERIDIAN_SCALE * ( northing_factor + equator_factor * Math.tan(lat_radians) * (origin_factor ** 2) / 2 + (5 - squared_lat_tangent + 9 * ecc_prime_factor + 4 * (ecc_prime_factor ** 2)) * (origin_factor ** 4) / 2 +
   (61 - 58 * squared_lat_tangent + (squared_lat_tangent ** 2) + 600 * ecc_prime_factor - 330 * ECC_PRIME_SQUARED) *
   (origin_factor ** 6) / 720))

  utm_northing += 10000000 if utm_northing < 0

  UtmPoint.new(
    easting: utm_easting.round,
    northing: utm_northing.round,
    zone: zone,
    hemisphere: (lat < 0 ? 'S' : 'N')
  )
end

.utm_to_usng(easting, northing, zone_number, zone_letter, hemisphere = 'N') ⇒ Object 



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# File 'lib/geo_swap.rb', line 63

def utm_to_usng(easting, northing, zone_number, zone_letter, hemisphere = 'N')
  precision = 10
  if hemisphere == 'S'
    northing += NORTHING_OFFSET
  end

  letters = find_grid_letters(zone_number, northing, easting)
  usngNorthing = (northing % BLOCK_SIZE).round
  usngEasting = (easting % BLOCK_SIZE).round

  "#{zone_number}#{zone_letter} #{letters} #{usngEasting} #{usngNorthing}"
end