Converts the JSON format used by "Zombies Run!" to GPX which can be imported in Runtastic.

zombies2gpx.go

package main

import (
	"fmt"
	"os"
	"time"
	"encoding/json"
	"encoding/xml"
)

type zombiesLog struct {
	Gps []struct {
		Altitude           float64   `json:"altitude"`
		HorizontalAccuracy float64   `json:"horizontal_accuracy"`
		Latitude           float64   `json:"latitude"`
		Longitude          float64   `json:"longitude"`
		Time               time.Time `json:"time"`
		VerticalAccuracy   float64   `json:"vertical_accuracy"`
	} `json:"gps"`
	StartTime time.Time `json:"start_time"`
}

type gpx struct {
	Gpx struct {
		Creator        string `xml:"creator,attr"`
		Version        string `xml:"version,attr"`
		Xsi            string `xml:"xsi,attr"`
		SchemaLocation string `xml:"schemaLocation,attr"`
		Trk            struct {
			Name   string `xml:"name"`
			Trkseg struct {
				Trkpt []trkPoints `xml:"trkpt"`
			} `xml:"trkseg"`
		} `xml:"trk"`
	} `xml:"gpx"`
}

type trkPoints struct {
	Lat  string `xml:"lat,attr"`
	Lon  string `xml:"lon,attr"`
	Ele  string `xml:"ele"`
	Time string `xml:"time"`
}

func main() {
	// specify the input file as commandline argument
	dat, err := os.Open(os.Args[1])
	check(err)

	var zombiesJSON zombiesLog
	err = json.NewDecoder(dat).Decode(&zombiesJSON)
	check(err)

	var runtasticGPX gpx

	// fill header values
	runtasticGPX.Gpx.Creator = "zombies2gpx"
	runtasticGPX.Gpx.Version = "1.0"
	runtasticGPX.Gpx.SchemaLocation = "http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd"
	runtasticGPX.Gpx.Xsi = "http://www.w3.org/2001/XMLSchema-instance"

	// array for the trackpoints
	runtasticPoints := make([]trkPoints, len(zombiesJSON.Gps))

	// copy all trackpoints to the GPX xml stuct
	for index, trackpoint := range zombiesJSON.Gps {
		runtasticPoints[index] = trkPoints{
			Lat:  fmt.Sprintf("%f", trackpoint.Latitude),
			Lon:  fmt.Sprintf("%f", trackpoint.Longitude),
			Ele:  fmt.Sprintf("%f", trackpoint.Altitude),
			Time: trackpoint.Time.Format(time.RFC3339),
		}

	}
	runtasticGPX.Gpx.Trk.Trkseg.Trkpt = runtasticPoints

	enc := xml.NewEncoder(os.Stdout)
	enc.Indent("  ", "    ")

	err = enc.Encode(runtasticGPX)
	check(err)

}

func check(e error) {
	if e != nil {
		panic(e)
	}
}

Great little tool! I've been looking for a way to extract the run logs out of the app, this (along with your blog post) was just what I needed - thanks!