convert the data format of ZweiteGPS

zweitegps-json2gpx.rb

#!/usr/bin/env ruby

# NOTE: currently, convert "trk" only. this does not consider "wpt" and "rte" yet.

require 'json'
require 'rexml/document'
require 'time'

json_file = ARGV[0]

MEANS_MASTER = {
  :"0" => "Walking",
  :"1" => "Jogging",
  :"2" => "Bicycle",
  :"3" => "MotorCycle",
  :"4" => "AutoMobile",
  :"5" => "Train",
  :"6" => "Misc",
}

additional_info = {
  trk_name: [],
  creator: [],
  asset: [],
  means: [],
}

boundsType = {
  minlat: 90,
  maxlat: -90,
  minlon: 180,
  maxlon: -180,
}

document = REXML::Document.new
document << REXML::XMLDecl.new('1.0', 'UTF-8')

gpx = REXML::Element.new 'gpx'
gpx.attributes['version'] = '1.1'
gpx.attributes['creator'] = 'ZweiteGPS'

trk = REXML::Element.new 'trk'

trkseg = REXML::Element.new 'trkseg'

# trkpt(s)
open(json_file) do |io|
  JSON.load(io).each do |coordinate|

    trkpt = REXML::Element.new 'trkpt'
    trkpt.attributes['lat'] = coordinate['la'].to_s
    trkpt.attributes['lon'] = coordinate['lo'].to_s

    if coordinate['al']
      ele = REXML::Element.new 'ele'
      ele.add_text( coordinate['al'].to_s )
      trkpt.add( ele )
    end

    if coordinate['tm']
      time = REXML::Element.new 'time'
      time.add_text( Time.at(coordinate['tm']).utc.iso8601.to_s )
      trkpt.add( time )
    end

    # if coordinate['he']
    #   magvar = REXML::Element.new 'magvar'
    #   magvar.add_text( coordinate['he'].to_s )
    #   trkpt.add( magvar )
    # end

    # if coordinate['dp']
    #   desc = REXML::Element.new 'desc'
    #   desc.add_text( coordinate['dp'].to_s )
    #   trkpt.add( desc )
    # end

    # if coordinate['ln']
    #   link = REXML::Element.new 'link'
    #   link.attributes['href'] = coordinate['ln'].to_s
    #   trkpt.add( link )
    # end

    # if coordinate['ha']
    #   hdop = REXML::Element.new 'hdop'
    #   hdop.add_text( coordinate['ha'].to_s )
    #   trkpt.add( hdop )
    # end

    # if coordinate['va']
    #   vdop = REXML::Element.new 'vdop'
    #   vdop.add_text( coordinate['va'].to_s )
    #   trkpt.add( vdop )
    # end

    # get additional information if it exists
    if coordinate['ow']
      additional_info[:creator] << coordinate['ow'].to_s
    end
    if coordinate['tl']
      additional_info[:trk_name] << coordinate['tl'].to_s
    end
    if coordinate['as']
      additional_info[:asset] << coordinate['as'].to_s
    end
    if coordinate['ms']
      additional_info[:means] << coordinate['ms'].to_s
    end

    trkseg << trkpt

    # by the way, update bounds
    if coordinate['la']    < boundsType[:minlat]
       boundsType[:minlat] = coordinate['la']
    end
    if boundsType[:maxlat] < coordinate['la']
       boundsType[:maxlat] = coordinate['la']
    end
    if coordinate['lo']    < boundsType[:minlon]
       boundsType[:minlon] = coordinate['lo']
    end
    if boundsType[:maxlon] < coordinate['lo']
       boundsType[:maxlon] = coordinate['lo']
    end

  end
end

# overwrite "creator" of gpx if it exists
unless additional_info[:creator].empty?
  additional_info[:creator].compact!
  gpx.attributes['creator'] = additional_info[:creator].first
  if 1 < additional_info[:creator].size
    warn "found multipule 'creator' data";
  end
end

# update "name" of trk if it exists
unless additional_info[:trk_name].empty?
  additional_info[:trk_name].compact!
  name = REXML::Element.new 'name'
  name.add_text( additional_info[:trk_name].first )
  trk.add( name )
  if 1 < additional_info[:trk_name].size
    warn "found multipule 'trk_name' data";
  end
end

# gpx metadata
metadata = REXML::Element.new 'metadata'
unless additional_info[:means].empty?
  name = REXML::Element.new 'name'
  name.add_text( MEANS_MASTER[additional_info[:means].first.to_s.to_sym] )
  metadata.add( name )
  if 1 < additional_info[:means].size
    warn "found multipule 'means' data";
  end
end
# gpx matadata children - 'time'
gpx_metadata_time = REXML::Element.new 'time'
gpx_metadata_time.add_text(Time.now.utc.iso8601.to_s)
metadata.add( gpx_metadata_time )
# gpx matadata children - 'bounds'
bounds = REXML::Element.new 'bounds'
bounds.attributes['minlat'] = boundsType[:minlat].to_s
bounds.attributes['minlon'] = boundsType[:minlon].to_s
bounds.attributes['maxlat'] = boundsType[:maxlat].to_s
bounds.attributes['maxlon'] = boundsType[:maxlon].to_s
metadata.add( bounds )

trk << trkseg

gpx << metadata
gpx << trk

document << gpx
document.write $stdout