+ def to_s
+ "Element #{@type}/#{@id} has duplicate tags with key #{@tag_key}"
+ end
+ end
+
+ # Raised when a way has more than the configured number of way nodes.
+ # This prevents ways from being to long and difficult to work with
+ class APITooManyWayNodesError < APIError
+ def initialize(id, provided, max)
+ @id, @provided, @max = id, provided, max
+ end
+
+ attr_reader :id, :provided, :max
+
+ def status
+ :bad_request
+ end
+
+ def to_s
+ "You tried to add #{provided} nodes to way #{id}, however only #{max} are allowed"
+ end
+ end
+
+ ##
+ # raised when user input couldn't be parsed
+ class APIBadUserInput < APIError
+ def initialize(message)
+ @message = message
+ end
+
+ def status
+ :bad_request
+ end
+
+ def to_s
+ @message
+ end
+ end
+
+ ##
+ # raised when bounding box is invalid
+ class APIBadBoundingBox < APIError
+ def initialize(message)
+ @message = message
+ end
+
+ def status
+ :bad_request
+ end
+
+ def to_s
+ @message
+ end
+ end
+
+ ##
+ # raised when an API call is made using a method not supported on that URI
+ class APIBadMethodError < APIError
+ def initialize(supported_method)
+ @supported_method = supported_method
+ end
+
+ def status
+ :method_not_allowed
+ end
+
+ def to_s
+ "Only method #{@supported_method} is supported on this URI"
+ end
+ end
+
+ ##
+ # raised when an API call takes too long
+ class APITimeoutError < APIError
+ def status
+ :request_timeout
+ end
+
+ def to_s
+ "Request timed out"
+ end
+ end
+
+ # Helper methods for going to/from mercator and lat/lng.
+ class Mercator
+ include Math
+
+ #init me with your bounding box and the size of your image
+ def initialize(min_lat, min_lon, max_lat, max_lon, width, height)
+ xsize = xsheet(max_lon) - xsheet(min_lon)
+ ysize = ysheet(max_lat) - ysheet(min_lat)
+ xscale = xsize / width
+ yscale = ysize / height
+ scale = [xscale, yscale].max
+
+ xpad = width * scale - xsize
+ ypad = height * scale - ysize
+
+ @width = width
+ @height = height
+
+ @tx = xsheet(min_lon) - xpad / 2
+ @ty = ysheet(min_lat) - ypad / 2
+
+ @bx = xsheet(max_lon) + xpad / 2
+ @by = ysheet(max_lat) + ypad / 2
+ end
+
+ #the following two functions will give you the x/y on the entire sheet
+
+ def ysheet(lat)
+ log(tan(PI / 4 + (lat * PI / 180 / 2))) / (PI / 180)
+ end
+
+ def xsheet(lon)
+ lon
+ end
+
+ #and these two will give you the right points on your image. all the constants can be reduced to speed things up. FIXME
+
+ def y(lat)
+ return @height - ((ysheet(lat) - @ty) / (@by - @ty) * @height)
+ end
+
+ def x(lon)
+ return ((xsheet(lon) - @tx) / (@bx - @tx) * @width)
+ end