Class: String

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

Instance Method Summary collapse

Instance Method Details

#coordinates(datum = :osgb36, options = {}) ⇒ Object

Treats the string as a coordinate pair, if that can be done. Any two decimal numbers, positive or negative, separated by any non-digit (and non -) characters are acceptable.

"54.196763, -3.093320".coordinates      # -> [54.196763, -3.093320]



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# File 'lib/osgb/string_conversions.rb', line 48

def coordinates(datum=:osgb36, options={})
  if matches = self.match(/(-?\d+\.\d+)[^\d\-]+(-?\d+\.\d+)/)
    lat,lng = matches[1,2]
    Osgb::Point.new(lat, lng, datum, options[:precision])
  else
    nil
  end
end

#is_gridref? ⇒ Boolean

Returns true if the string is a valid grid reference: that is, it consits of two valid square-designation letters then 4, 6, 8 or 10 digits. Invalid, malformed and just plain not a grid reference will all return false.

Returns:

  • (Boolean) 


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# File 'lib/osgb/string_conversions.rb', line 10

def is_gridref?
  !!(self.upcase =~ /^(H(P|T|U|Y|Z)|N(A|B|C|D|F|G|H|J|K|L|M|N|O|R|S|T|U|W|X|Y|Z)|OV|S(C|D|E|G|H|J|K|M|N|O|P|R|S|T|U|W|X|Y|Z)|T(A|F|G|L|M|Q|R|V)){1}\d{4}(NE|NW|SE|SW)?$|((H(P|T|U|Y|Z)|N(A|B|C|D|F|G|H|J|K|L|M|N|O|R|S|T|U|W|X|Y|Z)|OV|S(C|D|E|G|H|J|K|M|N|O|P|R|S|T|U|W|X|Y|Z)|T(A|F|G|L|M|Q|R|V)){1}(\d{4}|\d{6}|\d{8}|\d{10}))$/)
end

#is_latlng? ⇒ Boolean

Returns true if the string can be decomposed into a valid lat/long co-ordinate pair.

Returns:

  • (Boolean) 


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# File 'lib/osgb/string_conversions.rb', line 31

def is_latlng?
  coordinates && coordinates.valid?
end

#lat(options = {}) ⇒ Object

Returns the latitude component of the string, however it can be found. Works for both coordinate pairs and grid references. Defaults to WGS84 if coming from a grid reference.



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# File 'lib/osgb/string_conversions.rb', line 116

def lat(options={})
  to_latlng(options).lat
end

#lng(options = {}) ⇒ Object

Returns the longitude component of the string, however it can be found. Works for both coordinate pairs and grid references. Defaults to WGS84 if coming from a grid reference.



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# File 'lib/osgb/string_conversions.rb', line 124

def lng(options={})
  to_latlng(options).lng
end

#resembles_gridref? ⇒ Boolean

Returns true if the string looks like a grid reference, whether or not it is well-formed or valid on the ground. In validation this may allow you to distinguish between mistaken and irrelevant input.

“HD123456”.resembles_gridref? # -> true “HD123456”.is_gridref? # -> false “SD12345”.resembles_gridref? # -> true “SD12345”.is_gridref? # -> false “WC1 1AA”.resembles_gridref? # -> false

Returns:

  • (Boolean) 


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# File 'lib/osgb/string_conversions.rb', line 24

def resembles_gridref?
  !!(self.upcase =~ /^\w\w\d{2,}/)
end

#resembles_latlng? ⇒ Boolean

Returns true if the string can be decomposed into a co-ordinate pair, regardless of whether the coordinates are valid.

Returns:

  • (Boolean) 


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# File 'lib/osgb/string_conversions.rb', line 38

def resembles_latlng?
  !!coordinates
end

#to_latlng(options = {}) ⇒ Object

If the string is a valid grid reference, this returns the lat/long point using the specified or default datum. Default is WGS84 for GPS compatibility.



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# File 'lib/osgb/string_conversions.rb', line 60

def to_latlng(options={})
  if is_gridref?
    Osgb::Gridref.new(self, options).to_latlng(options[:datum])
  else
    self.coordinates(options[:datum])
  end
end

#to_latlng!(options = {}) ⇒ Object

Returns the grid reference as a lat/long pair on the specified or default datum, raising an exception if it is not valid.



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# File 'lib/osgb/string_conversions.rb', line 71

def to_latlng!(options={})
  with_validity_check { to_latlng(options) }
end

#to_osgb36(options = {}) ⇒ Object

If the string is a valid grid reference, this returns the coordinate pair using the OSGB36 datum, which is the native representation for grid references.



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# File 'lib/osgb/string_conversions.rb', line 78

def to_osgb36(options={})
  if is_gridref?
    Osgb::Gridref.new(self, options).to_latlng(:osgb36)
  else
    self.coordinates(:osgb36, options)
  end
end

#to_osgb36!(options = {}) ⇒ Object

Returns the grid reference as a lat/long pair on OSGB36, raising an exception if it is not valid.



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# File 'lib/osgb/string_conversions.rb', line 89

def to_osgb36!(options={})
  with_validity_check { to_osgb36(options) }
end

#to_wgs84(options = {}) ⇒ Object

If the string is a valid grid reference, this returns the coordinate pair using the WGS84 datum, which is the most suitable representation for work with GPS or google maps.



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# File 'lib/osgb/string_conversions.rb', line 97

def to_wgs84(options={})
  if is_gridref?
    Osgb::Gridref.new(self, options).to_latlng(:wgs84)
  else
    self.coordinates(:wgs84, options)
  end
end

#to_wgs84!(options = {}) ⇒ Object

Returns the grid reference as a lat/long pair on WGS84, raising an exception if it is not valid.



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# File 'lib/osgb/string_conversions.rb', line 108

def to_wgs84!(options={})
  with_validity_check { to_wgs84(options) }
end