Class: GeoHex::Zone

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

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*params) ⇒ Zone

Returns a new instance of Zone.

Raises:

  • (ArgumentError) 


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

def initialize(*params)
  raise ArgumentError, "latlng or code is needed" if params.size == 0
  if params.first.is_a?(Float)
    @lat,@lon = params[0],params[1]
    @level= params[2]||7 
    @code= GeoHex::Zone.encode(@lat,@lon,@level)
  else
    @code = params.first
    @lat,@lon,@level=GeoHex::Zone.decode(@code)
  end
end

Instance Attribute Details

#code ⇒ Object

Returns the value of attribute code.



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# File 'lib/geohex.rb', line 19

def code
  @code
end

#lat ⇒ Object

Returns the value of attribute lat.



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# File 'lib/geohex.rb', line 19

def lat
  @lat
end

#lon ⇒ Object

Returns the value of attribute lon.



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# File 'lib/geohex.rb', line 19

def lon
  @lon
end

#x ⇒ Object

Returns the value of attribute x.



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# File 'lib/geohex.rb', line 19

def x
  @x
end

#y ⇒ Object

Returns the value of attribute y.



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# File 'lib/geohex.rb', line 19

def y
  @y
end

Class Method Details

.calcHexSize(level) ⇒ Object 



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# File 'lib/geohex.rb', line 32

def self.calcHexSize(level)
  H_BASE/(2**level)/3
end

.decode(code) ⇒ Object

geohex to latlon



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# File 'lib/geohex.rb', line 146

def self.decode(code)
  c_length = code.length;
  level = H_KEY.index(code[0,1]);
  scl = level;
  h_size =  self.calcHexSize(level);
  unit_x = 6.0 * h_size;
  unit_y = 6.0 * h_size * H_K;
  h_max = (H_BASE / unit_x + H_BASE / unit_y).round;
  h_x = 0;
  h_y = 0;

  if (h_max >= 12960000 / 2) 
    h_x = H_KEY.index(code[1,1]) * 12960000 + 
      H_KEY.index(code[3,1]) * 216000 + 
      H_KEY.index(code[5,1]) * 3600 + 
      H_KEY.index(code[7,1]) * 60 + 
      H_KEY.index(code[9,1]);
    h_y = H_KEY.index(code[2,1]) * 12960000 + 
      H_KEY.index(code[4,1]) * 216000 + 
      H_KEY.index(code[6,1]) * 3600 + 
      H_KEY.index(code[8,1]) * 60 + 
      H_KEY.index(code[10,1]);
  elsif (h_max >= 216000 / 2) 
    h_x = H_KEY.index(code[1,1]) * 216000 + 
      H_KEY.index(code[3,1]) * 3600 + 
      H_KEY.index(code[5,1]) * 60 + 
      H_KEY.index(code[7,1]);
    h_y = H_KEY.index(code[2,1]) * 216000 + 
      H_KEY.index(code[4,1]) * 3600 + 
      H_KEY.index(code[6,1]) * 60 + 
      H_KEY.index(code[8,1]);
  elsif (h_max >= 3600 / 2) 
    h_x = H_KEY.index(code[1,1]) * 3600 + 
      H_KEY.index(code[3,1]) * 60 + 
      H_KEY.index(code[5,1]);
		h_y = H_KEY.index(code[2,1]) * 3600 + 
      H_KEY.index(code[4,1]) * 60 + 
      H_KEY.index(code[6,1]);
  elsif (h_max >= 60 / 2) 
    h_x = H_KEY.index(code[1,1]) * 60 + 
      H_KEY.index(code[3,1]);
    h_y = H_KEY.index(code[2,1]) * 60 + 
      H_KEY.index(code[4,1]);
  else
    h_x = H_KEY.index(code[1,1]);
    h_y = H_KEY.index(code[2,1]);
  end
  h_x = (h_x % 2 == 1) ? -(h_x - 1) / 2 : h_x / 2;
  h_y = (h_y % 2 == 1) ? -(h_y - 1) / 2 : h_y / 2;

  h_lat_y = (H_K * h_x * unit_x + h_y * unit_y) / 2;
  h_lon_x = (h_lat_y - h_y * unit_y) / H_K;

  h_loc = xy2loc(h_lon_x, h_lat_y);
  return [h_loc.lat, h_loc.lon, level]
end

.encode(lat, lon, level = 7) ⇒ Object

latlon to geohex

Raises:

  • (ArgumentError) 


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# File 'lib/geohex.rb', line 70

def self.encode(lat,lon,level=7)
  raise ArgumentError, "latitude must be double" unless (lat.is_a?(Numeric))
  raise ArgumentError, "latitude must be between -85 and 85" if (lat < -85.1 || lat > 85.1)
  raise ArgumentError, "latitude must be between -85 and 85" if (lat < -85.1 || lat > 85.1)
  raise ArgumentError, "longitude must be between -180 and 180" if (lon < -180 || lon > 180)
  raise ArgumentError, "level must be between 0 and 24" if (level < 0 || level > 24)
  
  h_size = self.calcHexSize(level)
  z_xy = loc2xy(lon,lat)
  lon_grid = z_xy.x
  lat_grid = z_xy.y
  unit_x = 6.0* h_size;
  unit_y = 6.0* 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;
  
  h_max=(H_BASE/unit_x + H_BASE/unit_y).round;
  
  if ( h_y_q > -h_x_q + 1 ) 
    if ( h_y_q < (2 * h_x_q ) and  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_x_p = (h_x<0) ? 1 : 0;
  h_y_p = (h_y<0) ? 1 : 0;
  h_x_abs = ((h_x).abs * 2 + h_x_p).to_f;
  h_y_abs = ((h_y).abs * 2 + h_y_p).to_f;
  h_x_10000 = ((h_x_abs%777600000)/12960000).floor;
  h_x_1000 = ((h_x_abs%12960000)/216000).floor;
  h_x_100 = ((h_x_abs%216000)/3600).floor;
  h_x_10 = ((h_x_abs%3600)/60).floor;
  h_x_1 = ((h_x_abs%3600)%60).floor;
  h_y_10000 = ((h_y_abs%77600000)/12960000).floor;
  h_y_1000 = ((h_y_abs%12960000)/216000).floor;
  h_y_100 = ((h_y_abs%216000)/3600).floor;
  h_y_10 = ((h_y_abs%3600)/60).floor;
  h_y_1 = ((h_y_abs%3600)%60).floor;
  h_code = H_KEY[level % 60, 1];
  h_code += H_KEY[h_x_10000, 1]+H_KEY[h_y_10000, 1] if(h_max >=12960000/2) ;
  h_code += H_KEY[h_x_1000, 1]+H_KEY[h_y_1000, 1] if(h_max >=216000/2) ;
  h_code += H_KEY[h_x_100, 1]+H_KEY[h_y_100, 1] if(h_max >=3600/2) ;
  h_code += H_KEY[h_x_10, 1]+H_KEY[h_y_10, 1] if(h_max >=60/2) ;
  h_code += H_KEY[h_x_1, 1]+H_KEY[h_y_1, 1];
  
  return h_code;
end

.loc2xy(_lon, _lat) ⇒ Object 



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# File 'lib/geohex.rb', line 205

def loc2xy(_lon,_lat) 
  x=_lon*H_BASE/180;
  y= Math.log(Math.tan((90+_lat)*Math::PI/360)) / (Math::PI / 180 );
  y= y * H_BASE / 180;
  return OpenStruct.new("x"=>x, "y"=>y);
end

.xy2loc(_x, _y) ⇒ Object 



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# File 'lib/geohex.rb', line 212

def xy2loc(_x,_y) 
  lon=(_x/H_BASE)*180;
  lat=(_y/H_BASE)*180;
lat=180.0/Math::PI*(2.0*Math.atan(Math.exp(lat*Math::PI/180))-Math::PI/2);
  return OpenStruct.new("lon" => lon,"lat" => lat);
end

Instance Method Details

#hexCoords ⇒ Object 



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# File 'lib/geohex.rb', line 43

def hexCoords
  h_lat = self.lat;
  h_lon = self.lon;
  h_xy = GeoHex::Zone.loc2xy(h_lon, h_lat);
  h_x = h_xy.x
  h_y = h_xy.y
  h_deg = Math.tan(Math::PI * (60 / 180));
  h_size = self.hexSize
  h_top = xy2loc(h_x, h_y + h_deg *  h_size).lat;
  h_btm = xy2loc(h_x, h_y - h_deg *  h_size).lat;
  
  h_l = xy2loc(h_x - 2 * h_size, h_y).lon;
  h_r = xy2loc(h_x + 2 * h_size, h_y).lon;
  h_cl = xy2loc(h_x - 1 * h_size, h_y).lon;
  h_cr = xy2loc(h_x + 1 * h_size, h_y).lon;
  
  [
   {:lat => h_lat, :lon => h_l},
   {:lat => h_top, :lon => h_cl},
   {:lat => h_top, :lon => h_cr},
   {:lat => h_lat, :lon => h_r},
   {:lat => h_btm, :lon => h_cr},
   {:lat => h_btm, :lon => h_cl}
  ]
end

#hexSize ⇒ Object 



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# File 'lib/geohex.rb', line 39

def hexSize
  self.calcHexSize(self.level)
end

#level ⇒ Object 



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# File 'lib/geohex.rb', line 36

def level
  H_KEY.index(code[0,1])
end