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.


14
15
16
17
18
19
20
21
# 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._coordsys_3857,
                                                    buffer_resolution: opts[:buffer_resolution],
                                                    has_z_coordinate: opts[:has_z_coordinate],
                                                    has_m_coordinate: opts[:has_m_coordinate])
end

Instance Attribute Details

#projection_factoryObject (readonly)

Returns the value of attribute projection_factory.


28
29
30
# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 28

def projection_factory
  @projection_factory
end

Class Method Details

._coordsys_3857Object

:nodoc:


107
108
109
110
111
# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 107

def self._coordsys_3857 # :nodoc:
  return @coordsys_3857 if defined?(@coordsys_3857)

  @coordsys_3857 = CoordSys::CONFIG.default_coord_sys_class.create(3857)
end

Instance Method Details

#limits_windowObject


94
95
96
97
98
99
100
101
102
103
104
105
# 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


30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
# 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


23
24
25
26
# 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


59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
# 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)

90
91
92
# File 'lib/rgeo/geographic/simple_mercator_projector.rb', line 90

def wraps?
  true
end