Class: GeoHex::Zone

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

Overview

A positioned instance of a Unit, within a level-grid

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(x, y, level) ⇒ Zone

Returns a new instance of Zone.

Parameters:

  • x (Integer) —

    the horizontal index

  • y (Integer) —

    the vertical index

  • level (Integer) —

    the level



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# File 'lib/geo_hex/zone.rb', line 21

def initialize(x, y, level)
  @x, @y    = x, y
  @unit     = Unit[level]
  @northing = (H_K * @x * @unit.width + @y * @unit.height) / 2.0
  @easting  = (@northing - @y * @unit.height) / H_K
  @x, @y    = @y, @x if meridian_180?
end

Instance Attribute Details

#easting ⇒ Float (readonly)

Returns the mercator easting.

Returns:

  • (Float) —

    the mercator easting



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# File 'lib/geo_hex/zone.rb', line 16

def easting
  @easting
end

#northing ⇒ Float (readonly)

Returns the mercator northing.

Returns:

  • (Float) —

    the mercator northing



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# File 'lib/geo_hex/zone.rb', line 13

def northing
  @northing
end

#unit ⇒ GeoHex::Unit (readonly)

Returns the associated unit.

Returns:



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# File 'lib/geo_hex/zone.rb', line 10

def unit
  @unit
end

#x ⇒ Integer (readonly)

Returns the zone coordinates within the grid.

Returns:

  • (Integer) —

    the zone coordinates within the grid



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# File 'lib/geo_hex/zone.rb', line 7

def x
  @x
end

#y ⇒ Integer (readonly)

Returns the zone coordinates within the grid.

Returns:

  • (Integer) —

    the zone coordinates within the grid



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# File 'lib/geo_hex/zone.rb', line 7

def y
  @y
end

Instance Method Details

#==(other) ⇒ Boolean Also known as: eql?

Returns true, if given Zone or GeoHex code (String) matches self.

Parameters:

  • other (Zone, String) —

    another Zone or a GeoHex code (String)

Returns:

  • (Boolean) —

    true, if given Zone or GeoHex code (String) matches self



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# File 'lib/geo_hex/zone.rb', line 85

def ==(other)
  case other
  when String
    to_s == other
  when self.class
    x == other.x && y == other.y && level == other.level
  else
    super
  end
end

#code ⇒ String Also known as: to_s

Returns GeoHex code.

Returns:

  • (String) —

    GeoHex code



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# File 'lib/geo_hex/zone.rb', line 45

def code
  @code ||= encode
end

#hash ⇒ Fixnum

Returns the object hash.

Returns:

  • (Fixnum) —

    the object hash



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# File 'lib/geo_hex/zone.rb', line 98

def hash
  [x, y, level].hash
end

#lat ⇒ Float

Returns the latitude coordinate.

Returns:

  • (Float) —

    the latitude coordinate



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# File 'lib/geo_hex/zone.rb', line 40

def lat
  point.lat
end

#level ⇒ Integer

Returns the level.

Returns:

  • (Integer) —

    the level



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# File 'lib/geo_hex/zone.rb', line 30

def level
  unit.level
end

#lon ⇒ Float

Returns the longitude coordinate.

Returns:

  • (Float) —

    the longitude coordinate



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# File 'lib/geo_hex/zone.rb', line 35

def lon
  meridian_180? ? 180.0 : point.lon
end

#meridian_180? ⇒ Boolean

Returns true if the zone is placed on the 180th meridian.

Returns:

  • (Boolean) —

    true if the zone is placed on the 180th meridian



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# File 'lib/geo_hex/zone.rb', line 108

def meridian_180?
  return @meridian_180 if defined?(@meridian_180)
  @meridian_180 = H_BASE - easting < unit.size
end

#neighbours(range = 1) ⇒ Array<GeoHex::Zone> Also known as: neighbors

Returns the neighbouring zones.

Parameters:

  • range (Integer) (defaults to: 1) —

    the number of zones to search within

Returns:



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# File 'lib/geo_hex/zone.rb', line 62

def neighbours(range = 1)
  zones  = []
  x0, xn = x - range, x + range

  x0.upto(xn) do |xi|
    zones << self.class.new(xi, y, level) unless xi == x
  end

  1.upto(range) do |i|
    y+i % 2 == 1 ? xn-=1 : x0+=1

    x0.upto(xn) do |xi|
      zones << self.class.new(xi, y+i, level)
      zones << self.class.new(xi-i, y-i, level)
    end
  end

  zones
end

#point ⇒ GeoHex::PP

Returns zone center, point coordinates.

Returns:



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# File 'lib/geo_hex/zone.rb', line 51

def point
  @point ||= GeoHex::PP.new(easting, northing)
end

#polygon ⇒ <GeoHex::Polygon>

Returns Zone’s NE, E, SE, SW, W and NW points.

Returns:



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# File 'lib/geo_hex/zone.rb', line 56

def polygon
  @polygon ||= GeoHex::Polygon.new(easting, northing, unit.size)
end

#to_a ⇒ Array

Returns x, y & level tuple.

Returns:

  • (Array) —

    x, y & level tuple



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# File 'lib/geo_hex/zone.rb', line 103

def to_a
  [x, y, level]
end