Class: Mormon::Tile::Data

Inherits:
Object
  • Object
show all
Defined in:
lib/mormon/tile_data.rb

Constant Summary collapse

TILE_DIR = 
'cache/%d/%d/%d'
TILE_URL = 
'http://dev.openstreetmap.org/~ojw/api/?/map/%d/%d/%d'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Data

Returns a new instance of Data.



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# File 'lib/mormon/tile_data.rb', line 12

def initialize(options = {})
  @options = options
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/mormon/tile_data.rb', line 10

def options
  @options
end

Class Method Details

.download_level ⇒ Object 



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# File 'lib/mormon/tile_data.rb', line 16

def self.download_level
  # All primary downloads are done at a particular zoom level
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end

Instance Method Details

#get_osm(z, x, y) ⇒ Object 



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# File 'lib/mormon/tile_data.rb', line 21

def get_osm(z, x, y)
  # Download OSM data for the region covering a slippy-map tile
  if x < 0 or y < 0 or z < 0 or z > 25
    puts "Disallowed %d,%d at %d" % [x, y, z]
    return
  end
  
  directory = TILE_DIR % [z,x,y]
  FileUtils.mkdir_p(directory) unless Dir.exists?(directory)
  
  if z == Data.download_level
    url = TILE_URL % [z,x,y]
    filename = '%s/data.osm' % directory

    # puts "URL: %s" % url
    # puts "filename: %s" % filename

    # download the data
    if options[:reset_cache] || !File.exists?(filename)
      begin
        open(url) do |content|
          File.new(filename) { |f| f.write content }
        end
        filename
      rescue OpenURI::HTTPError
        "Tile not found in #{url}"
      end
    end
    
  elsif z > Data.download_level
    # use larger tile
    while z > Data.download_level
      z = z - 1
      x = (x / 2).to_i
      y = (y / 2).to_i
    end
    get_osm z, x, y
  end

end