Module: Locapoint

Defined in:
lib/locapoint/locapoint.rb,
lib/locapoint/version.rb

Overview

LocaPoint module.

Defined Under Namespace

Modules: VERSION Classes: FormatError

Constant Summary collapse

LOCAPOINT_REGEXP =

Regular expression that matches LocaPoint strings.

/[A-Z][A-Z][0-9]\.[A-Z][A-Z][0-9]\.[A-Z][A-Z][0-9]\.[A-Z][A-Z][0-9]/

Class Method Summary collapse

Class Method Details

.decode(locapoint) ⇒ Object

Will convert a LocaPoint string into a pair of latitude and longitude.



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# File 'lib/locapoint/locapoint.rb', line 15

def self.decode(locapoint)
  unless locapoint =~ LOCAPOINT_REGEXP && locapoint.size == 15
    raise FormatError, "Invalid format"
  end
  
  s = locapoint.to_s
  latitude = ((s[0] - ?A) * 1757600 \
              +(s[1] - ?A) * 67600 \
              +(s[2] - ?0) * 6760 \
              +(s[8] - ?A) * 260 \
              +(s[9] - ?A) * 10 \
              +(s[10] - ?0) ) * 180 / 45697600.0 -90;
  longitude = ((s[4] - ?A) * 1757600 \
               +(s[5] - ?A) * 67600 \
               +(s[6] - ?0) * 6760 \
               +(s[12] - ?A) * 260 \
               +(s[13] - ?A) * 10 \
               +(s[14] - ?0) ) * 360 / 45697600.0 -180;
  return latitude, longitude
end

.encode(latitude, longitude) ⇒ Object

Will convert latitude and longitude into LocaPoint string.



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# File 'lib/locapoint/locapoint.rb', line 37

def self.encode(latitude, longitude)
  latitude_step = (latitude.to_f + 90) / 180 * 45697600;
  longitude_step = (longitude.to_f + 180) / 360 * 45697600;
  
  s = "AA0.AA0.AA0.AA0"
  s[0] += (latitude_step / 1757600 % 26).to_i
  s[1] += (latitude_step / 67600 % 26).to_i
  s[2] += (latitude_step / 6760 % 10).to_i
  
  s[4] += (longitude_step / 1757600 % 26).to_i
  s[5] += (longitude_step / 67600 % 26).to_i
  s[6] += (longitude_step / 6760 % 10).to_i

  s[8] += (latitude_step / 260 % 26).to_i
  s[9] += (latitude_step / 10 % 26).to_i
  s[10] += (latitude_step / 1 % 10).to_i
  
  s[12] += (longitude_step / 260 % 26).to_i
  s[13] += (longitude_step / 10 % 26).to_i
  s[14] += (longitude_step / 1 % 10).to_i

  return s
end