Class: RGeo::Geographic::SimpleMercatorProjector

Inherits:
Object
  • Object
show all
Defined in:
lib/rgeo/geographic/simple_mercator_projector.rb

Overview

:nodoc:

Constant Summary collapse

EQUATORIAL_RADIUS = 
6_378_137.0

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(geography_factory, opts = {}) ⇒ SimpleMercatorProjector

Returns a new instance of SimpleMercatorProjector.



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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 14

def initialize(geography_factory, opts = {})
  @geography_factory = geography_factory
  @projection_factory = Cartesian.preferred_factory(srid: 3857,
                                                    coord_sys: SimpleMercatorProjector._coordsys3857,
                                                    buffer_resolution: opts[:buffer_resolution],
                                                    has_z_coordinate: opts[:has_z_coordinate],
                                                    has_m_coordinate: opts[:has_m_coordinate])
end

Instance Attribute Details

#projection_factory ⇒ Object (readonly)

Returns the value of attribute projection_factory.



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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 28

def projection_factory
  @projection_factory
end

Class Method Details

._coordsys3857 ⇒ Object

:nodoc:



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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 107

def self._coordsys3857 # :nodoc:
  return @coordsys3857 if defined?(@coordsys3857)

  @coordsys3857 = CoordSys::CONFIG.default_coord_sys_class.create(3857)
end

Instance Method Details

#limits_window ⇒ Object 



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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 94

def limits_window
  return @limits_window if defined?(@limits_window)

  @limits_window = ProjectedWindow.new(
    @geography_factory,
    -20_037_508.342789,
    -20_037_508.342789,
    20_037_508.342789,
    20_037_508.342789,
    is_limits: true
  )
end

#project(geometry) ⇒ Object 



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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 30

def project(geometry)
  case geometry
  when Feature::Point
    rpd_ = ImplHelper::Math::RADIANS_PER_DEGREE
    radius = EQUATORIAL_RADIUS
    @projection_factory.point(
      geometry.x * rpd_ * radius,
      Math.log(Math.tan(Math::PI / 4.0 + geometry.y * rpd_ / 2.0)) * radius
    )
  when Feature::Line
    @projection_factory.line(project(geometry.start_point), project(geometry.end_point))
  when Feature::LinearRing
    @projection_factory.linear_ring(geometry.points.map { |p| project(p) })
  when Feature::LineString
    @projection_factory.line_string(geometry.points.map { |p| project(p) })
  when Feature::Polygon
    @projection_factory.polygon(project(geometry.exterior_ring),
                                geometry.interior_rings.map { |p| project(p) })
  when Feature::MultiPoint
    @projection_factory.multi_point(geometry.map { |p| project(p) })
  when Feature::MultiLineString
    @projection_factory.multi_line_string(geometry.map { |p| project(p) })
  when Feature::MultiPolygon
    @projection_factory.multi_polygon(geometry.map { |p| project(p) })
  when Feature::GeometryCollection
    @projection_factory.collection(geometry.map { |p| project(p) })
  end
end

#set_factories(geography_factory, projection_factory) ⇒ Object 



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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 23

def set_factories(geography_factory, projection_factory)
  @geography_factory = geography_factory
  @projection_factory = projection_factory
end

#unproject(geometry) ⇒ Object 



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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 59

def unproject(geometry)
  case geometry
  when Feature::Point
    dpr = ImplHelper::Math::DEGREES_PER_RADIAN
    radius = EQUATORIAL_RADIUS
    @geography_factory.point(
      geometry.x / radius * dpr,
      (2.0 * Math.atan(Math.exp(geometry.y / radius)) - Math::PI / 2.0) * dpr
    )
  when Feature::Line
    @geography_factory.line(unproject(geometry.start_point), unproject(geometry.end_point))
  when Feature::LinearRing
    @geography_factory.linear_ring(geometry.points.map { |p| unproject(p) })
  when Feature::LineString
    @geography_factory.line_string(geometry.points.map { |p| unproject(p) })
  when Feature::Polygon
    @geography_factory.polygon(
      unproject(geometry.exterior_ring),
      geometry.interior_rings.map { |p| unproject(p) }
    )
  when Feature::MultiPoint
    @geography_factory.multi_point(geometry.map { |p| unproject(p) })
  when Feature::MultiLineString
    @geography_factory.multi_line_string(geometry.map { |p| unproject(p) })
  when Feature::MultiPolygon
    @geography_factory.multi_polygon(geometry.map { |p| unproject(p) })
  when Feature::GeometryCollection
    @geography_factory.collection(geometry.map { |p| unproject(p) })
  end
end

#wraps? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 90

def wraps?
  true
end