Class: GPX::GPXFile

Inherits:
Base
  • Object
show all
Defined in:
lib/gpx/gpx_file.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Base

#instantiate_with_text_elements

Constructor Details

#initialize(opts = {}) ⇒ GPXFile

This initializer can be used to create a new GPXFile from an existing file or to create a new GPXFile instance with no data (so that you can add tracks and points and write it out to a new file later). To read an existing GPX file, do this:

gpx_file = GPXFile.new(:gpx_file => 'mygpxfile.gpx')
puts "Speed: #{gpx_file.average_speed}"
puts "Duration: #{gpx_file.duration}"
puts "Bounds: #{gpx_file.bounds}"

To create a new blank GPXFile instance:

gpx_file = GPXFile.new

Note that you can pass in any instance variables to this form of the initializer, including Tracks or Segments:

some_track = get_track_from_csv('some_other_format.csv')
gpx_file = GPXFile.new(:tracks => [some_track])



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# File 'lib/gpx/gpx_file.rb', line 43

def initialize(opts = {}) 
   @duration = 0
   if(opts[:gpx_file])
      gpx_file = opts[:gpx_file]
      case gpx_file
      when String
         gpx_file = File.open(gpx_file)
      end
      reset_meta_data
      @xml = Document.new(gpx_file, :ignore_whitespace_nodes => :all)

      bounds_element = (XPath.match(@xml, "/gpx/metadata/bounds").first rescue nil)
      if bounds_element
         @bounds.min_lat = bounds_element.attributes["min_lat"].to_f
         @bounds.min_lon = bounds_element.attributes["min_lon"].to_f
         @bounds.max_lat = bounds_element.attributes["max_lat"].to_f
         @bounds.max_lon = bounds_element.attributes["max_lon"].to_f
      else
         get_bounds = true
      end

      @tracks = XPath.match(@xml, "/gpx/trk").collect do |trk| 
         trk = Track.new(:element => trk, :gpx_file => self) 
         update_meta_data(trk, get_bounds)
         trk
      end
      @waypoints = XPath.match(@xml, "/gpx/wpt").collect { |wpt| Waypoint.new(:element => wpt, :gpx_file => self) }
      @routes =    XPath.match(@xml, "/gpx/rte").collect { |rte| Route.new(:element => rte, :gpx_file => self) }

      @tracks.delete_if { |t| t.empty? }

      calculate_duration
   else
      reset_meta_data
      opts.each { |attr_name, value| instance_variable_set("@#{attr_name.to_s}", value) }
      unless(@tracks.nil? or @tracks.size.zero?)
         @tracks.each { |trk| update_meta_data(trk) }
         calculate_duration
      end
   end
end

Instance Attribute Details

#average_speed(opts = { :units => 'kilometers' }) ⇒ Object (readonly)

Returns the average speed, in km/hr, meters/hr, or miles/hr, of this GPXFile. The calculation is based on the total distance divided by the total duration of the entire file.



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# File 'lib/gpx/gpx_file.rb', line 101

def average_speed
  @average_speed
end

#bounds ⇒ Object (readonly)

Returns the value of attribute bounds.



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# File 'lib/gpx/gpx_file.rb', line 25

def bounds
  @bounds
end

#distance(opts = { :units => 'kilometers' }) ⇒ Object (readonly)

Returns the distance, in kilometers, meters, or miles, of all of the tracks and segments contained in this GPXFile.



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# File 'lib/gpx/gpx_file.rb', line 87

def distance
  @distance
end

#duration ⇒ Object (readonly)

Returns the value of attribute duration.



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# File 'lib/gpx/gpx_file.rb', line 25

def duration
  @duration
end

#highest_point ⇒ Object (readonly)

Returns the value of attribute highest_point.



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# File 'lib/gpx/gpx_file.rb', line 25

def highest_point
  @highest_point
end

#lowest_point ⇒ Object (readonly)

Returns the value of attribute lowest_point.



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# File 'lib/gpx/gpx_file.rb', line 25

def lowest_point
  @lowest_point
end

#routes ⇒ Object (readonly)

Returns the value of attribute routes.



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# File 'lib/gpx/gpx_file.rb', line 25

def routes
  @routes
end

#tracks ⇒ Object (readonly)

Returns the value of attribute tracks.



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# File 'lib/gpx/gpx_file.rb', line 25

def tracks
  @tracks
end

#waypoints ⇒ Object (readonly)

Returns the value of attribute waypoints.



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# File 'lib/gpx/gpx_file.rb', line 25

def waypoints
  @waypoints
end

Instance Method Details

#crop(area) ⇒ Object

Crops any points falling within a rectangular area. Identical to the delete_area method in every respect except that the points outside of the given area are deleted. Note that this method automatically causes the meta data to be updated after deletion.



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# File 'lib/gpx/gpx_file.rb', line 116

def crop(area)
   reset_meta_data
   keep_tracks = []
   tracks.each do |trk| 
      trk.crop(area) 
      unless trk.empty?
         update_meta_data(trk)
         keep_tracks << trk 
      end
   end
   @tracks = keep_tracks
   routes.each { |rte| rte.crop(area) }
   waypoints.each { |wpt| wpt.crop(area) }
end

#delete_area(area) ⇒ Object

Deletes any points falling within a rectangular area. The “area” parameter is usually an instance of the Bounds class. Note that this method cascades into similarly named methods of subordinate classes (i.e. Track, Segment), which means, if you want the deletion to apply to all the data, you only call this one (and not the one in Track or Segment classes). Note that this method automatically causes the meta data to be updated after deletion.



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# File 'lib/gpx/gpx_file.rb', line 138

def delete_area(area)
   reset_meta_data
   keep_tracks = []
   tracks.each do |trk| 
      trk.delete_area(area) 
      unless trk.empty?
         update_meta_data(trk)
         keep_tracks << trk 
      end
   end
   @tracks =  keep_tracks
   routes.each { |rte| rte.delete_area(area) }
   waypoints.each { |wpt| wpt.delete_area(area) }
end

#reset_meta_data ⇒ Object

Resets the meta data for this GPX file. Meta data includes the bounds, the high and low points, and the distance.



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# File 'lib/gpx/gpx_file.rb', line 155

def reset_meta_data
   @bounds = Bounds.new
   @highest_point = nil
   @lowest_point = nil
   @distance = 0.0
end

#update_meta_data(trk, get_bounds = true) ⇒ Object

Updates the meta data for this GPX file. Meta data includes the bounds, the high and low points, and the distance. This is useful when you modify the GPX data (i.e. by adding or deleting points) and you want the meta data to accurately reflect the new data.



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# File 'lib/gpx/gpx_file.rb', line 166

def update_meta_data(trk, get_bounds = true)
   @lowest_point   = trk.lowest_point if(@lowest_point.nil? or trk.lowest_point.elevation < @lowest_point.elevation)
   @highest_point  = trk.highest_point if(@highest_point.nil? or trk.highest_point.elevation > @highest_point.elevation)
   @bounds.add(trk.bounds) if get_bounds
   @distance += trk.distance
end

#write(filename) ⇒ Object

Serialize the current GPXFile to a gpx file named <filename>. If the file does not exist, it is created. If it does exist, it is overwritten.



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# File 'lib/gpx/gpx_file.rb', line 175

def write(filename)

   doc = Document.new
   gpx_elem = Element.new('gpx')
   doc.add(gpx_elem)
   gpx_elem.attributes['xmlns:xsi'] = "http://www.w3.org/2001/XMLSchema-instance" 
   gpx_elem.attributes['xmlns'] = "http://www.topografix.com/GPX/1/1" 
   gpx_elem.attributes['version'] = "1.1" 
   gpx_elem.attributes['creator'] = "GPX RubyGem 0.1 Copyright 2006 Doug Fales -- http://walkingboss.com" 
   gpx_elem.attributes['xsi:schemaLocation'] = "http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd"

   meta_data_elem = Element.new('metadata')
   name_elem = Element.new('name')
   name_elem.text = File.basename(filename)
   meta_data_elem.elements << name_elem

   time_elem = Element.new('time')
   time_elem.text = Time.now.xmlschema
   meta_data_elem.elements << time_elem

   meta_data_elem.elements << bounds.to_xml

   gpx_elem.elements << meta_data_elem

   tracks.each    { |t|   gpx_elem.add_element t.to_xml } unless tracks.nil?
   waypoints.each { |w| gpx_elem.add_element w.to_xml } unless waypoints.nil?
   routes.each    { |r| gpx_elem.add_element r.to_xml } unless routes.nil?

   File.open(filename, 'w') { |f| doc.write(f) }
end