Class: GoobyGpxParser

Inherits:
GoobyBaseSaxParser show all
Defined in:
lib/gooby_gpx_parser.rb

Overview

Gooby = Google APIs + Ruby. Copyright 2009 by Chris Joakim. Gooby is available under GNU General Public License (GPL) license.

This class is used to parse a gpx xml file, such as from MotionX GPS software on an iPhone.

This implementation, based on one sample file, handles a gpx file with one ‘trk’. A future implementation may handle multiple ‘trk’ elements per document, as well as ‘trkseg’ aggregates. The observed structure of a gpx document is:

gpx
gpx|trk
gpx|trk|name
gpx|trk|desc
gpx|trk|trkseg
gpx|trk|trkseg|trkpt
gpx|trk|trkseg|trkpt|ele
gpx|trk|trkseg|trkpt|time

Instance Attribute Summary

Attributes inherited from GoobyBaseSaxParser

#current_tagname, #end_reached, #error, #exception, #list, #mappings, #xml

Instance Method Summary collapse

Methods inherited from GoobyBaseSaxParser

#end_reached?, #get_current_text, #has_error?, #has_exception?, #initialize, #on_cdata_block, #on_characters, #on_end_document, #on_error, #process_file, #process_xml, #set_error

Constructor Details

This class inherits a constructor from GoobyBaseSaxParser

Instance Method Details

#current_path ⇒ Object 



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# File 'lib/gooby_gpx_parser.rb', line 60

def current_path
  @tags.join('|')
end

#on_end_element(name, prefix = nil, uri = nil) ⇒ Object 



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# File 'lib/gooby_gpx_parser.rb', line 45

def on_end_element(name, prefix=nil, uri=nil)
  path = current_path
  if path == 'gpx|trk|name'
    @name = get_current_text
  elsif path == 'gpx|trk|desc'
    @desc = get_current_text
  elsif path == 'gpx|trk|trkseg|trkpt|ele'
    @current_trackpoint.set('AltitudeMeters', get_current_text)
  elsif path == 'gpx|trk|trkseg|trkpt|time'
    @current_trackpoint.set('Time', get_current_text)
  end 
  @current_text = ''
  @tags.pop
end

#on_start_element(name, attributes, prefix = nil, uri = nil, namespaces = nil) ⇒ Object 



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# File 'lib/gooby_gpx_parser.rb', line 32

def on_start_element(name, attributes, prefix=nil, uri=nil, namespaces=nil)
  @tags.push(name) 
  @current_text = ''
  path = current_path
  if path == 'gpx|trk|trkseg|trkpt'
    @current_trackpoint = GoobyTrackpoint.new
    @current_trackpoint.set('LatitudeDegrees',  attributes['lat'])
    @current_trackpoint.set('LongitudeDegrees', attributes['lon'])
    @current_trackpoint.set('Time', get_current_text)      
    @trackpoints << @current_trackpoint
  end
end

#post_process ⇒ Object

Coumpute the elapsed time and distance of each Trackpoint within the Activity.



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# File 'lib/gooby_gpx_parser.rb', line 65

def post_process
  cumulative_distance, first_tkpt_dttm, prev_tkpt, activ_id = 0.0, nil, nil, @name
  @trackpoints.each_with_index { | tkpt, idx |
    if prev_tkpt
      incremental_distance = tkpt.proximity(prev_tkpt)
      cumulative_distance = cumulative_distance + incremental_distance
      tkpt.set('Distance', cumulative_distance)
    else
      first_tkpt_dttm = tkpt.dttm
      tkpt.set('Distance', 0.0)
      if activ_id.size < 1
        activ_id = first_tkpt_dttm
      end
    end
    tkpt.set('Seq', idx + 1)
    tkpt.set('LapSeq', 1)
    tkpt.set('ActivityId', activ_id)
    tkpt.set('LapStartTime', first_tkpt_dttm)
    tkpt.compute_elapsed_time(first_tkpt_dttm)
    tkpt.compute_cumulative_pace_and_mph(first_tkpt_dttm)
    prev_tkpt = tkpt
  }
end

#subclass_initialize ⇒ Object 



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# File 'lib/gooby_gpx_parser.rb', line 27

def subclass_initialize
  @tags, @trackpoints, @mappings,  = [], [], {}, 
  @name, @desc = '', ''
end

#trackpoints_to_csv ⇒ Object 



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# File 'lib/gooby_gpx_parser.rb', line 89

def trackpoints_to_csv
  lines = []
  @trackpoints.each { | tkpt | 
    lines << tkpt.to_csv
  }
  lines
end