Class: Geospatial::Filter

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

Defined Under Namespace

Classes: Range

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(curve) ⇒ Filter

Returns a new instance of Filter.



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# File 'lib/geospatial/filter.rb', line 55

def initialize(curve)
  @ranges = []
  @curve = curve
end

Instance Attribute Details

#ranges ⇒ Object (readonly)

Returns the value of attribute ranges.



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# File 'lib/geospatial/filter.rb', line 60

def ranges
  @ranges
end

Instance Method Details

#add(prefix, order) ⇒ Object 



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# File 'lib/geospatial/filter.rb', line 62

def add(prefix, order)
  if last = @ranges.last
    raise ArgumentError.new("Cannot add non-sequential prefix") unless prefix > last.max
  end
  
  unless last = @ranges.last and last.expand!(prefix, order)
    @ranges << Range.new(prefix, order)
  end
end

#apply(points) ⇒ Object Also known as: & 



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# File 'lib/geospatial/filter.rb', line 72

def apply(points)
  # This is a poor implementation.
  points.select{|point| @ranges.any?{|range| range.include?(point.hash)}}
end

#each(depth: 0) ⇒ Object 



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# File 'lib/geospatial/filter.rb', line 83

def each(depth: 0)
  # TODO using a range tree might allow a significantly improved implementation.
  @curve.traverse do |child_origin, child_size, prefix, order|
    child = Box.new(Vector.elements(child_origin), Vector.elements(child_size))
    
    # puts "Considering (order=#{order}) #{child.inspect}..."
    
    min = prefix
    max = prefix | ((1 << (order*2)) - 1)
    
    if min_range = find(min)
      if order == depth # at bottom
        yield(child, prefix, order); :skip
      elsif min_range.include?(max)
        # This range completely contains the current prefix/order
        yield(child, prefix, order); :skip
      else
        # go deeper
      end
    elsif max_range = find(max)
      if order == depth # at bottom
        yield(child, prefix, order); :skip
      else
        # go deeper
      end
    elsif sub_range = @ranges.find{|range| range.min >= min && range.max <= max}
      # go deeper
    else
      :skip # out of bounds
    end
  end
end

#find(hash) ⇒ Object 



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# File 'lib/geospatial/filter.rb', line 116

def find(hash)
  @ranges.find{|range| range.include?(hash)}
end

#include?(point) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/geospatial/filter.rb', line 79

def include?(point)
  @ranges.any?{|range| range.include?(point.hash)}
end