Module: Iarea::Utils

Defined in:
lib/iarea/utils.rb

Overview

Utility module

Constant Summary collapse

LAT_WIDTH = 
[nil,2400000,300000,150000, 75000,37500,18750, 9375  ]
LON_WIDTH = 
[nil,3600000,450000,225000,112500,56250,28125,14062.5]

Class Method Summary collapse

Class Method Details

.expand_meshcode(meshcode) ⇒ Object

Return array of 1th..7th meshcodes for the given 7th meshcode



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# File 'lib/iarea/utils.rb', line 32

def expand_meshcode(meshcode)
  (6..12).map do |n|
    meshcode[0, n]
  end
end

.lat_lng_to_meshcode(lat_deg, lng_deg) ⇒ Object

Return 7th meshcode of given coordinates



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# File 'lib/iarea/utils.rb', line 8

def lat_lng_to_meshcode(lat_deg, lng_deg)
  lat = (lat_deg * 3600000).to_i
  lng = (lng_deg * 3600000).to_i
  meshcode = ''
  la = lat
  lo = lng - 100*60*60*1000
  for i in 1..7
    a = (la / LAT_WIDTH[i]).to_i
    b = (lo / LON_WIDTH[i]).to_i
    la -= a * LAT_WIDTH[i]
    lo -= b * LON_WIDTH[i]
    case i
    when 1
      meshcode = sprintf("%02d%02d",a,b)
    when 2
      meshcode << sprintf("%d%d",a,b)
    else
      meshcode << sprintf("%d",a*2+b)
    end
  end
  return meshcode
end