exiftool create gpx track

#------------------------------------------------------------------------------
# File:         gpx.fmt
#
# Description:  Example ExifTool print format file to generate a GPX track log
#
# Usage:        exiftool -p gpx.fmt -ee3 FILE [...] > out.gpx
#
# Requires:     ExifTool version 10.49 or later
#
# Revisions:    2010/02/05 - P. Harvey created
#               2018/01/04 - PH Added IF to be sure position exists
#               2018/01/06 - PH Use DateFmt function instead of -d option
#               2019/10/24 - PH Preserve sub-seconds in GPSDateTime value
#
# Notes:     1) Input file(s) must contain GPSLatitude and GPSLongitude.
#            2) The -ee3 option is to extract the full track from video files.
#            3) The -fileOrder option may be used to control the order of the
#               generated track points when processing multiple files.
#------------------------------------------------------------------------------
#[HEAD]<?xml version="1.0" encoding="utf-8"?>
#[HEAD]<gpx version="1.0"
#[HEAD] creator="ExifTool $ExifToolVersion"
#[HEAD] xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
#[HEAD] xmlns="http://www.topografix.com/GPX/1/0"
#[HEAD] xsi:schemaLocation="http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd">
#[HEAD]<trk>
#[HEAD]<number>1</number>
#[HEAD]<trkseg>
#[IF]  $gpslatitude $gpslongitude
#[BODY]<trkpt lat="$gpslatitude#" lon="$gpslongitude#">
#[BODY]  <ele>$gpsaltitude#</ele>
#[BODY]  <time>${gpsdatetime#;my ($ss)=/\.\d+/g;DateFmt("%Y-%m-%dT%H:%M:%SZ");s/Z/${ss}Z/ if $ss}</time>
#[BODY]</trkpt>
#[TAIL]</trkseg>
#[TAIL]</trk>
#[TAIL]</gpx>