Module: Terraformer::Bounds

Defined in:
lib/terraformer/bounds.rb

Class Method Summary collapse

Class Method Details

.bounds(obj, format = :bbox) ⇒ Object 



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# File 'lib/terraformer/bounds.rb', line 6

def bounds obj, format = :bbox

  obj = Terraformer.parse obj unless Geometry === obj

  bbox = case obj.type
         when 'Point'
           [ obj.coordinates[0], obj.coordinates[1],
             obj.coordinates[0], obj.coordinates[1] ]
         when 'MultiPoint'
           bounds_for_array obj.coordinates
         when 'LineString'
           bounds_for_array obj.coordinates
         when 'MultiLineString'
           bounds_for_array obj.coordinates, 1
         when 'Polygon'
           bounds_for_array obj.coordinates, 1
         when 'MultiPolygon'
           bounds_for_array obj.coordinates, 2
         when 'Feature'
           obj.geometry ? bounds(obj.geometry) : nil
         when 'FeatureCollection'
           bounds_for_feature_collection obj
         when 'GeometryCollection'
           bounds_for_geometry_collection obj
         else
           raise ArgumentError.new 'unknown type: ' + obj.type
         end

  case format
  when :bbox
    bbox
  when :polygon
    Polygon.new [[bbox[0], bbox[1]],
                 [bbox[0], bbox[3]],
                 [bbox[2], bbox[3]],
                 [bbox[2], bbox[1]],
                 [bbox[0], bbox[1]]]
  end
end

.bounds_for_array(array, nesting = 0, box = Array.new(4)) ⇒ Object 



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# File 'lib/terraformer/bounds.rb', line 48

def bounds_for_array array, nesting = 0, box = Array.new(4)
  if nesting > 0
    array.reduce box do |b, a|
      bounds_for_array a, (nesting - 1), b
    end
  else
    bbox = array.reduce box do |b, lonlat|
      lon, lat = *lonlat
      set = ->(d, i, t){ b[i] = d if b[i].nil? or d.send(t, b[i])}
      set[lon, X1, :<]
      set[lon, X2, :>]
      set[lat, Y1, :<]
      set[lat, Y2, :>]
      b
    end
    bbox
  end
end

.bounds_for_collection(collection) ⇒ Object 



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# File 'lib/terraformer/bounds.rb', line 75

def bounds_for_collection collection
  bounds_for_array collection.map {|e| bounds(block_given? ? yield(e) : e)}
end

.bounds_for_feature_collection(fc) ⇒ Object 



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# File 'lib/terraformer/bounds.rb', line 67

def bounds_for_feature_collection fc
  bounds_for_collection fc.features, &:geometry
end

.bounds_for_geometry_collection(gc) ⇒ Object 



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# File 'lib/terraformer/bounds.rb', line 71

def bounds_for_geometry_collection gc
  bounds_for_collection gc
end

.envelope(geometry) ⇒ Object 



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# File 'lib/terraformer/bounds.rb', line 80

def envelope geometry
  b = bounds geometry
  {
    x: b[0],
    y: b[1],
    w: (b[0] - b[2]).abs,
    h: (b[1] - b[3]).abs
  }
end