Class: Geohex::V3::Zone

Inherits:
Object
  • Object
show all
Defined in:
lib/geohex/v3/zone.rb

Constant Summary collapse

H_KEY = 
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
H_BASE = 
20037508.34
H_DEG = 
Math::PI * (30.0 / 180)
H_K = 
Math.tan(H_DEG)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#code ⇒ Object (readonly)

Returns the value of attribute code.



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# File 'lib/geohex/v3/zone.rb', line 14

def code
  @code
end

#latitude ⇒ Object (readonly) Also known as: lat

Returns the value of attribute latitude.



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# File 'lib/geohex/v3/zone.rb', line 14

def latitude
  @latitude
end

#level ⇒ Object (readonly)

Returns the value of attribute level.



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# File 'lib/geohex/v3/zone.rb', line 14

def level
  @level
end

#longitude ⇒ Object (readonly) Also known as: lon

Returns the value of attribute longitude.



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# File 'lib/geohex/v3/zone.rb', line 14

def longitude
  @longitude
end

#x ⇒ Object (readonly)

Returns the value of attribute x.



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# File 'lib/geohex/v3/zone.rb', line 15

def x
  @x
end

#y ⇒ Object (readonly)

Returns the value of attribute y.



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# File 'lib/geohex/v3/zone.rb', line 15

def y
  @y
end

Class Method Details

.decode(code) ⇒ Object 



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# File 'lib/geohex/v3/zone.rb', line 25

def decode code
  instance = self.new
  instance.decode code

  instance
end

.encode(latitude, longitude, level) ⇒ Object 



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# File 'lib/geohex/v3/zone.rb', line 20

def encode latitude, longitude, level
  instance = self.new
  instance.encode latitude, longitude, level
end

Instance Method Details

#decode(code) ⇒ Object 



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# File 'lib/geohex/v3/zone.rb', line 156

def decode code
  level = code.length
  @level = code.length - 2
  h_size = calcHexSize(level)

  unit_x = 6 * h_size
  unit_y = 6 * h_size * H_K
  h_x = 0
  h_y = 0
  h_dec9 = ((H_KEY.index(code.slice(0, 1)) * 30) + H_KEY.index(code.slice(1, 1))).to_s + code.slice(2, code.length)

  if h_dec9.slice(0, 1).match(/[15]/) and h_dec9.slice(1, 1).match(/[^125]/) and h_dec9.slice(2, 1).match(/[^125]/)
    if h_dec9.slice(0, 1) == "5"
      h_dec9 = "7" + h_dec9.slice(1, h_dec9.length)
    else
      h_dec9 = "3" + h_dec9.slice(1, h_dec9.length)
    end
  end

  d9xlen = h_dec9.length

  (level + 1 - d9xlen).times do
    h_dec9 = "0" + h_dec9
    d9xlen += 1
  end

  h_dec3 = ""
  d9xlen.times do |i|
    h_dec0 = h_dec9.slice(i, 1).to_i.to_s(3)

    if h_dec0.length == 1
      h_dec3 += "0"
    end
    h_dec3 += h_dec0
  end

  h_decx = []
  h_decy = []

  (h_dec3.length / 2).times do |i|
    h_decx << h_dec3.slice(i * 2, 1)
    h_decy << h_dec3.slice(i * 2 + 1, 1)
  end

  (level + 1).times do |i|
    h_pow = (3 ** (level - i))
    case h_decx[i].to_i
    when 0
      h_x -= h_pow
    when 2
      h_x += h_pow
    end

    case h_decy[i].to_i
    when 0
      h_y -= h_pow
    when 2
      h_y += h_pow
    end
  end

  h_x, h_y, rev = adjust_xy h_x, h_y, @level

  @latitude, @longitude, @x, @y, @code = getZoneByXY h_x, h_y, @level

  [@latitude, @longitude, @x, @y, @code]
end

#encode(latitude, longitude, level = 7) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/geohex/v3/zone.rb', line 56

def encode latitude, longitude, level = 7
  raise ArgumentError, "latitude must be between -90 and 90" unless (-90..90).include? latitude
  raise ArgumentError, "longitude must be between -180 and 180" unless (-180..180).include? longitude
  raise ArgumentError, "level must be between 0 and 15" unless (0..15).include? level

  @level = level
  level += 2
  h_size = calcHexSize(@level)

  z_xy = loc2xy(longitude, latitude)
  lon_grid = z_xy.x
  lat_grid = z_xy.y
  unit_x = 6 * h_size
  unit_y = 6 * h_size * H_K
  h_pos_x = (lon_grid + lat_grid / H_K) / unit_x
  h_pos_y = (lat_grid - H_K * lon_grid) / unit_y
  h_x_0 = h_pos_x.floor
  h_y_0 = h_pos_y.floor
  h_x_q = h_pos_x - h_x_0
  h_y_q = h_pos_y - h_y_0
  h_x = h_pos_x.round
  h_y = h_pos_y.round

  if (h_y_q > (-h_x_q) + 1)
    if((h_y_q < 2 * h_x_q) && (h_y_q > 0.5 * h_x_q))
      h_x = h_x_0 + 1
      h_y = h_y_0 + 1
    end
  elsif (h_y_q < (-h_x_q) + 1)
    if ((h_y_q > (2 * h_x_q) - 1) && (h_y_q < (0.5 * h_x_q) + 0.5))
      h_x = h_x_0
      h_y = h_y_0
    end
  end

  h_lat = (H_K * h_x * unit_x + h_y * unit_y) / 2
  h_lon = (h_lat - h_y * unit_y) / H_K

  z_loc = xy2loc(h_lon, h_lat)
  z_loc_x = z_loc.lon
  z_loc_y = z_loc.lat
  if ((H_BASE - h_lon) < h_size)
    z_loc_x = 180.0
    h_xy = h_x
    h_x = h_y
    h_y = h_xy
  end

  h_code = ''
  code3_x = []
  code3_y = []
  code3 = ''
  code9 = ''
  mod_x = h_x
  mod_y = h_y

  (level + 1).times do |i|
    h_pow = (3 ** (level - i))

    if (mod_x >= (h_pow / 2.0).ceil)
      code3_x << 2
      mod_x -= h_pow
    elsif(mod_x <= -(h_pow / 2.0).ceil)
      code3_x << 0
      mod_x += h_pow
    else
      code3_x << 1
    end

    if (mod_y >= (h_pow / 2.0).ceil)
      code3_y << 2
      mod_y -= h_pow
    elsif (mod_y <= -(h_pow / 2.0).ceil)
      code3_y << 0
      mod_y += h_pow
    else
      code3_y << 1
    end
  end

  (code3_x.size).to_i.times do |i|
    code3 = "#{ code3_x[i] }#{ code3_y[i] }"
    code9 = code3.to_i(3).to_s
    h_code += code9.to_s
  end

  h_2  = h_code.slice(3, h_code.size).to_s
  h_1  = h_code.slice(0, 3).to_i
  h_a1 = (h_1 / 30).to_i
  h_a2 = h_1 % 30

  @code = "#{ H_KEY.slice(h_a1, 1) }#{ H_KEY.slice(h_a2, 1) }#{ h_2 }"
  @x = h_x
  @y = h_y
  @latitude = latitude
  @longitude = longitude

  @code
end