class Geospatial::Polygon
Attributes
points[R]
Public Class Methods
[](*points)
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# File lib/geospatial/polygon.rb, line 27 def self.[] *points self.new(points) end
dump(polygon)
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# File lib/geospatial/polygon.rb, line 37 def self.dump(polygon) if polygon JSON.dump(polygon.points.map(&:to_a)) end end
is_left(p0, p1, p2)
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# File lib/geospatial/polygon.rb, line 144 def self.is_left(p0, p1, p2) a = p1 - p0 b = p2 - p0 return (a[0] * b[1]) - (b[0] * a[1]) end
load(data)
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# File lib/geospatial/polygon.rb, line 31 def self.load(data) if data self.new(JSON.parse(data).map{|point| Vector.elements(point)}) end end
new(points, bounding_box = nil)
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# File lib/geospatial/polygon.rb, line 43 def initialize(points, bounding_box = nil) @points = points @bounding_box = bounding_box end
Public Instance Methods
[](index)
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# File lib/geospatial/polygon.rb, line 50 def [] index a = @points[index.floor] b = @points[index.ceil % @points.size] return a + (b - a) * (index % 1.0) end
area(radius = 1.0)
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@param [Float] radius The radius of the sphere on which to compute the area.
# File lib/geospatial/polygon.rb, line 83 def area(radius = 1.0) if @points.size > 2 area = 0.0 self.edges.each do |p1, p2| r1 = (p2[0] - p1[0]) * D2R r2 = 2 + Math::sin(p1[1] * D2R) + Math::sin(p2[1] * D2R) area += r1 * r2 end return (area * radius * radius / 2.0).abs else return 0.0 end end
bounding_box()
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# File lib/geospatial/polygon.rb, line 61 def bounding_box @bounding_box ||= Box.enclosing_points(@points).freeze end
edge_intersection(a, b)
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# File lib/geospatial/polygon.rb, line 187 def edge_intersection(a, b) line = Line.new(a, b) edges.each_with_index do |(pa, pb), i| edge = Line.new(pa, pb) if line.intersect?(edge) return i end end return nil end
edges() { |point, points| ... }
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# File lib/geospatial/polygon.rb, line 72 def edges return to_enum(:edges) unless block_given? size = @points.size @points.each_with_index do |point, index| yield point, @points[(index+1)%size] end end
freeze()
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Calls superclass method
# File lib/geospatial/polygon.rb, line 65 def freeze @points.freeze bounding_box.freeze super end
include?(other)
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# File lib/geospatial/polygon.rb, line 210 def include?(other) other.corners.all?{|corner| self.include_point?(corner)} end
include_point?(point)
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# File lib/geospatial/polygon.rb, line 173 def include_point?(point) return false unless bounding_box.include_point?(point) self.winding_number(point).odd? end
intersect?(other)
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# File lib/geospatial/polygon.rb, line 201 def intersect?(other) case other when Box intersect_with_box?(other) when Circle intersect_with_circle?(other) end end
intersect_with_box?(other)
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# File lib/geospatial/polygon.rb, line 179 def intersect_with_box?(other) return true if @points.any?{|point| other.include_point?(point)} return true if other.corners.any?{|corner| self.include_point?(corner)} return false end
simplify() { |last, point, next_point| ... }
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# File lib/geospatial/polygon.rb, line 100 def simplify simplified_points = @points.first(1) (1...@points.size).each do |index| point = @points[index] next_point = @points[(index+1) % @points.size] if yield(simplified_points.last, point, next_point) simplified_points << point end end self.class.new(simplified_points, bounding_box) end
subdivide() { |last, point, next_point| ... }
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@example polygon.subdivide do |a, b|
a = Geospatial::Location.new(*a) b = Geospatial::Location.new(*b) if a.distance_from(b) > maximum_distance a.midpoints(b, 2) end
end
# File lib/geospatial/polygon.rb, line 124 def subdivide simplified_points = @points.first(1) (1..@points.size).each do |index| point = @points[index % @points.size] next_point = @points[(index+1) % @points.size] if points = yield(simplified_points.last, point, next_point) simplified_points.concat(points) end # Polygons are represented by a closed sequence of points, but we need to subdivide by the last point at the first point too. However, we don't add the first point a 2nd time. if index < @points.size simplified_points << point end end self.class.new(simplified_points, bounding_box) end
to_s()
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# File lib/geospatial/polygon.rb, line 57 def to_s "#{self.class}#{@points.inspect}" end
winding_number(p)
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Test a 2D point for inclusion in the polygon. @param [Vector] p The point to test. @return [Number] The number of times the polygon winds around the point (0 if outside).
# File lib/geospatial/polygon.rb, line 154 def winding_number(p) count = 0 edges.each do |pa, pb| if pa[1] <= p[1] if pb[1] >= p[1] and Polygon.is_left(pa, pb, p) > 0 count += 1 end else if pb[1] <= p[1] and Polygon.is_left(pa, pb, p) < 0 count -= 1 end end end return count end