Class: RGeo::Cartesian::BoundingBox

Inherits:
Object
  • Object
show all
Defined in:
lib/rgeo/cartesian/bounding_box.rb

Overview

This is a bounding box for Cartesian data. The simple cartesian implementation uses this internally to compute envelopes. You may also use it directly to compute and represent bounding boxes.

A bounding box is a set of ranges in each dimension: X, Y, as well as Z and M if supported. You can compute a bounding box for one or more geometry objects by creating a new bounding box object, and adding the geometries to it. You may then query it for the bounds, or use it to determine whether it encloses other geometries or bounding boxes.

Instance Method Summary collapse

Constructor Details

#initialize(factory_, opts_ = {}) ⇒ BoundingBox

Create a new empty bounding box with the given factory.

The factory defines the coordinate system for the bounding box, and also defines whether it should track Z and M coordinates. All geometries will be cast to this factory when added to this bounding box, and any generated envelope geometry will have this as its factory.

Options include:

[:ignore_z] If true, ignore z coordinates even if the factory supports them. Default is false. [:ignore_m] If true, ignore m coordinates even if the factory supports them. Default is false.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 74

def initialize(factory_, opts_={})
  @factory = factory_
  @has_z = !opts_[:ignore_z] && factory_.property(:has_z_coordinate) ? true : false
  @has_m = !opts_[:ignore_m] && factory_.property(:has_m_coordinate) ? true : false
  @min_x = @max_x = @min_y = @max_y = @min_z = @max_z = @min_m = @max_m = nil
end

Instance Method Details

#_add_geometry(geometry_) ⇒ Object

:nodoc:



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 285

def _add_geometry(geometry_)  # :nodoc:
  case geometry_
  when Feature::Point
    _add_point(geometry_)
  when Feature::LineString
    geometry_.points.each{ |p_| _add_point(p_) }
  when Feature::Polygon
    geometry_.exterior_ring.points.each{ |p_| _add_point(p_) }
  when Feature::MultiPoint
    geometry_.each{ |p_| _add_point(p_) }
  when Feature::MultiLineString
    geometry_.each{ |line_| line_.points.each{ |p_| _add_point(p_) } }
  when Feature::MultiPolygon
    geometry_.each{ |poly_| poly_.exterior_ring.points.each{ |p_| _add_point(p_) } }
  when Feature::GeometryCollection
    geometry_.each{ |g_| _add_geometry(g_) }
  end
end

#_add_point(point_) ⇒ Object

:nodoc:



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 305

def _add_point(point_)  # :nodoc:
  if @min_x
    x_ = point_.x
    @min_x = x_ if x_ < @min_x
    @max_x = x_ if x_ > @max_x
    y_ = point_.y
    @min_y = y_ if y_ < @min_y
    @max_y = y_ if y_ > @max_y
    if @has_z
      z_ = point_.z
      @min_z = z_ if z_ < @min_z
      @max_z = z_ if z_ > @max_z
    end
    if @has_m
      m_ = point_.m
      @min_m = m_ if m_ < @min_m
      @max_m = m_ if m_ > @max_m
    end
  else
    @min_x = @max_x = point_.x
    @min_y = @max_y = point_.y
    @min_z = @max_z = point_.z if @has_z
    @min_m = @max_m = point_.m if @has_m
  end
end

#add(geometry_) ⇒ Object

Adjusts the extents of this bounding box to encomass the given object, which may be a geometry or another bounding box. Returns self.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 210

def add(geometry_)
  case geometry_
  when BoundingBox
    add(geometry_.min_point)
    add(geometry_.max_point)
  when Feature::Geometry
    if geometry_.factory == @factory
      _add_geometry(geometry_)
    else
      _add_geometry(Factory.cast(geometry_, @factory))
    end
  end
  self
end

#contains?(rhs_, opts_ = {}) ⇒ Boolean

Returns true if this bounding box contains the given object, which may be a geometry or another bounding box.

Supports these options:

:ignore_z Ignore the Z coordinate when testing, even if both objects have Z. Default is false. :ignore_m Ignore the M coordinate when testing, even if both objects have M. Default is false.

Returns:

  • (Boolean) 


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# File 'lib/rgeo/cartesian/bounding_box.rb', line 266

def contains?(rhs_, opts_={})
  if Feature::Geometry === rhs_
    contains?(BoundingBox.new(@factory).add(rhs_))
  elsif rhs_.empty?
    true
  elsif empty?
    false
  elsif @min_x > rhs_.min_x || @max_x < rhs_.max_x || @min_y > rhs_.min_y || @max_y < rhs_.max_y
    false
  elsif @has_m && rhs_.has_m && !opts_[:ignore_m] && (@min_m > rhs_.min_m || @max_m < rhs_.max_m)
    false
  elsif @has_z && rhs_.has_z && !opts_[:ignore_z] && (@min_z > rhs_.min_z || @max_z < rhs_.max_z)
    false
  else
    true
  end
end

#empty? ⇒ Boolean

Returns true if this bounding box is still empty.

Returns:

  • (Boolean) 


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# File 'lib/rgeo/cartesian/bounding_box.rb', line 101

def empty?
  @min_x.nil?
end

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

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/rgeo/cartesian/bounding_box.rb', line 82

def eql?(rhs_)  # :nodoc:
  rhs_.is_a?(BoundingBox) && @factory == rhs_.factory &&
    @min_x == rhs_.min_x && @max_x == rhs_.max_x &&
    @min_y == rhs_.min_y && @max_y == rhs_.max_y &&
    @min_z == rhs_.min_z && @max_z == rhs_.max_z &&
    @min_m == rhs_.min_m && @max_m == rhs_.max_m
end

#factory ⇒ Object

Returns the bounding box's factory.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 94

def factory
  @factory
end

#has_m ⇒ Object

Returns true if this bounding box tracks M coordinates.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 115

def has_m
  @has_m
end

#has_z ⇒ Object

Returns true if this bounding box tracks Z coordinates.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 108

def has_z
  @has_z
end

#max_m ⇒ Object

Returns the maximum M, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 171

def max_m
  @max_m
end

#max_point ⇒ Object

Returns a point representing the maximum extent in all dimensions, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 194

def max_point
  if @min_x
    extras_ = []
    extras_ << @max_z if @has_z
    extras_ << @max_m if @has_m
    @factory.point(@max_x, @max_y, *extras_)
  else
    nil
  end
end

#max_x ⇒ Object

Returns the maximum X, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 129

def max_x
  @max_x
end

#max_y ⇒ Object

Returns the maximum Y, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 143

def max_y
  @max_y
end

#max_z ⇒ Object

Returns the maximum Z, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 157

def max_z
  @max_z
end

#min_m ⇒ Object

Returns the minimum M, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 164

def min_m
  @min_m
end

#min_point ⇒ Object

Returns a point representing the minimum extent in all dimensions, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 179

def min_point
  if @min_x
    extras_ = []
    extras_ << @min_z if @has_z
    extras_ << @min_m if @has_m
    @factory.point(@min_x, @min_y, *extras_)
  else
    nil
  end
end

#min_x ⇒ Object

Returns the minimum X, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 122

def min_x
  @min_x
end

#min_y ⇒ Object

Returns the minimum Y, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 136

def min_y
  @min_y
end

#min_z ⇒ Object

Returns the minimum Z, or nil if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 150

def min_z
  @min_z
end

#to_geometry ⇒ Object

Converts this bounding box to an envelope polygon. Returns the empty collection if this bounding box is empty.



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# File 'lib/rgeo/cartesian/bounding_box.rb', line 229

def to_geometry
  if @min_x
    extras_ = []
    extras_ << @min_z if @has_z
    extras_ << @min_m if @has_m
    point_min_ = @factory.point(@min_x, @min_y, *extras_)
    if @min_x == @max_x && @min_y == @max_y
      point_min_
    else
      extras_ = []
      extras_ << @max_z if @has_z
      extras_ << @max_m if @has_m
      point_max_ = @factory.point(@max_x, @max_y, *extras_)
      if @min_x == @max_x || @min_y == @max_y
        @factory.line(point_min_, point_max_)
      else
        @factory.polygon(@factory.linear_ring(point_min_, @factory.point(@max_x, @min_y, *extras_), point_max_, @factory.point(@min_x, @max_y, *extras_), point_min_))
      end
    end
  else
    @factory.collection([])
  end
end