gpscsv - Man Page

gpscsv [-?] [--class MCLASS] [--count COUNT] [--cvt-isotime] [--debug LVL] [--device DEVICE] [--fields FIELDS] [--file FILE] [--header HEADER] [--help] [--host HOST] [--port PORT] [--seconds FIELDS] [--separator SEPARATOR] [--version] [-c MCLASS] [-D  LVL] [-f  FIELDS] [-h] [-n COUNT] [-V] [-x FIELDS] [host[:port[:device]]]

gpscsv is a simple Python program for reading a gpsd JSON data streams and outputting them in Comma Separated Values (CSV) format. It takes input from a specified gpsd and reports to standard output. The program runs until the gpsd dies, "-n COUNT" messages are processed, "-x SECONDS" have passed, or it is interrupted by ^C or other means.

One good use of gpscsv is to create CSV files for use with the gnuplot program.

The program accepts the following options:

-?,  -h,  --help

Show help information and exit.

-c MCLASS, --class MCLASS

Select the JSON class messages of type MCLASS. Default is TPV. .

--cvt-isotime

Convert fields named "time" from ISO time to UNIX time.

-D LVL, --debug LVL

Set debug level to LVL. Default 0. Higher arguments than 0 produce more debug output.

--device DEVICE

The DEVICE on the gpsd to connect to. Defaults to all.

-f FIELDS, -fields FIELDS

The FIELDS from the JSON message to dump to the output. Set FIELD to empty ('') for all fields Default varies by CLASS.

--file FILE

Read JSON from FILE instead of from gpsd..

--header HEADER

Set header style to HEADER. 0 for no header, 1 output fields as header, 2 send fields as a comment ('#'). Defaults to 1.

--host HOST

Connect to the gpsd on HOST. Defaults to localhost.

-n COUNT, --count COUNT

Exit after outputting COUNT records. Set COUNT to 0 to disable. Default is 0

--port PORT

Use PORT to connect to gpsd. Defaults to 2947.

--separator SEPARATOR

Use SEPARATOR as the field separator. Default separator is a comma (',').

-V,  --version

Show gpscsv version, and exit.

-x SECONDS, --seconds SECONDS

Exit after SECONDS number of seconds have passed. Set SECONDS to 0 to disable. Default is 0

Some basic examples, do them in exact order shown:

Grab 100 samples of time,lat,lon,altHAE:

  $ gpscsv -n 100 --cvt-isotime  > tpv.dat

Grab 100 samples of time,epx,epy,epv,eph,sep

  $ gpscsv -n 100 --cvt-isotime -f time,epx,epy,epv,eph,sep > ep.dat

Grab 100 samples of time,xdop,ydop,vdop,tdop,hdop,gdop,pdop

  $ gpscsv -n 100 --cvt-isotime -c SKY  > sky.dat

Grab 100 samples of time,nSat,uSat

  $ gpscsv -n 100 --cvt-isotime -c SKY -f time,nSat,uSat  > sat.dat

start gnuplot in interactive mode:

  $ gnuplot

Some gnuplot housekeeping:

  # this are csv files
  gnuplot> set datafile separator ','
  # use the first line as title
  gnuplot> set key autotitle columnhead
  # X axis is UNIT time in seconds.
  gnuplot> set xdata time
  gnuplot> set timefmt "%s"

Now to plot time vs latitude:

  gnuplot> plot 'tpv.dat' using 1:2

Then to plot longitude and altHAE, in separate plots:

  gnuplot> plot 'tpv.dat' using 1:3
  gnuplot> plot 'tpv.dat' using 1:4

Put both latitude and longitude on one plot:

  gnuplot> set y2tics
  gnuplot> plot 'tpv.dat' using 1:2, '' using 1:3 axes x1y2

Plot epx, epy, epv, eph, and sep in one plot:

  gnuplot> plot 'ep.dat' using 1:2, '' using 1:3, \
           '' using 1:4, '' using 1:5, '' using 1:6

Plot all the DOPs on one plot:

  gnuplot> plot 'sky.dat' using 1:2, '' using 1:3, '' using 1:4, \
           '' using 1:5, '' using 1:6, '' using 1:7, '' using 1:8

Plot nSat and uSat together:

  gnuplot> plot 'sat.dat' using 1:2, '' using 1:3

Lat/lon scatter plot:

  # x is no longer time
  gnuplot> set xdata
  gnuplot> plot 'tpv.dat' using 3:2 title 'fix'

gpsd(8),

Gary E. Miller <gem@rellim.com>.