Class: GeoWeb::Map

Inherits:
Object
  • Object
show all
Defined in:
lib/geoweb/map.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Map

Returns a new instance of Map.



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# File 'lib/geoweb/map.rb', line 13

def initialize(options={})
  @tile_width = options[:tile_width] || 256
  @tile_height = options[:tile_height] || 256
  @zoom = options[:zoom] || 1
  @boundaries = options[:boundaries] || {}

  @origin_tile = options[:origin_tile] || Coordinate.new(0, 0, @zoom)
  @origin_pixel = options[:origin_pixel] || Point.new(0, 0, @zoom)
#      @dimensions = Point.new(map_extent(@zoom, @tile_width), map_extent(@zoom, @tile_height))

#      @transformation = options[:transformation] || default_transformation
  @projection = options[:projection] || default_mercator_projection(options[:transformation])
end

Instance Attribute Details

#boundaries ⇒ Object

Returns the value of attribute boundaries.



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# File 'lib/geoweb/map.rb', line 5

def boundaries
  @boundaries
end

#projection ⇒ Object

, :transformation



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# File 'lib/geoweb/map.rb', line 4

def projection
  @projection
end

#tile_height ⇒ Object

Returns the value of attribute tile_height.



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# File 'lib/geoweb/map.rb', line 6

def tile_height
  @tile_height
end

#tile_width ⇒ Object

Returns the value of attribute tile_width.



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# File 'lib/geoweb/map.rb', line 6

def tile_width
  @tile_width
end

#zoom ⇒ Object

, :transformation



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# File 'lib/geoweb/map.rb', line 4

def zoom
  @zoom
end

Class Method Details

.map_extent(zoom, tile_size = 256) ⇒ Object

Calculates the map-size (width or height) given a tile size and specific zoom



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# File 'lib/geoweb/map.rb', line 9

def self.map_extent(zoom, tile_size=256)
  2 ** (zoom + Math::log(tile_size)/Math::log(2))
end

Instance Method Details

#absolute_point(offset) ⇒ Object 



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# File 'lib/geoweb/map.rb', line 35

def absolute_point(offset)
  (@origin_pixel + offset)
end

#coordinates_to_point(location) ⇒ Object

Faster, but is accurate only to zoom levels lesser than 17



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# File 'lib/geoweb/map.rb', line 47

def coordinates_to_point(location)
  lat, lon = location.lat, location.lon

  #Parece que ele faz isso pra representar como uma fração (sem sinal) de 2Pi
  #http://en.wikipedia.org/wiki/Longitude#Noting_and_calculating_longitude
  long_deg = (-180.0 - lon).abs
  long_ppd = width.to_f / 360.0
  long_ppdrad = width.to_f / (2.0 * Math::PI)
  px_x = long_deg * long_ppd

  e = Math::sin( lat * (1.0/180.0 * Math::PI) )
  e = 0.9999 if e > 0.9999
  e = -0.9999 if e < -0.9999
  px_y = (height / 2.0) + 0.5 * Math::log((1+e)/(1-e)) * (-long_ppdrad)

  return absolute_point(Point.new(px_x, px_y, zoom))
end

#height ⇒ Object 



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# File 'lib/geoweb/map.rb', line 29

def height; @height ||= GeoWeb::Map.map_extent(zoom, tile_height); end

#location_point(location) ⇒ Object

Return an x, y point on the map image for a given geographical location.



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# File 'lib/geoweb/map.rb', line 40

def location_point(location)
  coord = projection.location_coordinate(location).zoom_to(zoom)
  point = (coord - @origin_tile) * [@tile_width, @tile_height]
  return absolute_point(point)
end

#point_location(point) ⇒ Object

Return a geographical location on the map image for a given x, y point.



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# File 'lib/geoweb/map.rb', line 66

def point_location(point)
    # origin tile at maximum zoom
    hizoom_origin_tile = @origin_tile.zoom_to(Coordinate::MAX_ZOOM)

    # distance in tile widths from reference tile to point
    tiles_distance = relative_point(point) / [@tile_width, @tile_height]

    # distance in rows & columns at maximum zoom
    distance = Coordinate.new(tiles_distance.x, tiles_distance.y, zoom).zoom_to(Coordinate::MAX_ZOOM)
    distance.z = 0

    # absolute tile at maximum zoom
    tile = (hizoom_origin_tile + distance).round!
    tile = tile.zoom_to(zoom)

    location = projection.coordinate_location(tile)
    return location
end

#relative_point(point) ⇒ Object 



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# File 'lib/geoweb/map.rb', line 31

def relative_point(point)
  (point - @origin_pixel)
end

#width ⇒ Object

SAME AS DIMENSIONS, retirar isso



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# File 'lib/geoweb/map.rb', line 28

def width; @width ||= GeoWeb::Map.map_extent(zoom, tile_width); end