#!/bin/bash
# usage:
#   nmea2speedlog < nmea-log.txt > speedlog.csv
#
# convert NMEA track to CSV with speed over time

if [ $# -ne 0 ]; then
  echo "usage: nmea2speedlog < nmea-log.txt > speedlog.csv"
  exit
fi

grep -e "^\$GPRMC" -e "^\$GPGGA" -e "^\$GPVTG" -e "^\$GPGSA" | \
gpsbabel -t -i nmea -f - -x discard,hdop=10,vdop=20 -o xcsv,style=/etc/gpsbabel/style/csv_edit_track.style -F - | \
grep -v "\-999.000000" | \
tr "," " "  | \
awk '{print $6 , 3.6*$7}' | \
tr " ." ";,"

