gnuplot: Faulty sensor sometimes reading 0.00 - how to convert them to missing?

Question

I have a combination RPi/Arduino taking readings from several DHT-22 Humidity/Temperature sensors.

One of the sensors developed a loose wire and has been giving occasi

Answer 1

Gnuplot allows you to filter data while plotting:

gnuplot 'file.dat' using 1:($2 == 0.0 ? 1/0 : $2)

This treats all values of 0 as invalid points and those points are skipped. Depending on the selected plotting style that works, or not: plot ... with lines interrupts a line at an invalid point.

Since gnuplot version 5.0.6 you can use set datafile missing NaN to have invalid points treated as missing ones, and a line would simply ignore those points:

$data <<EOD
12
27
0
23
42
EOD

set multiplot layout 1,2

set title '0.0 invalid'
plot $data using 0:($1 == 0.0 ? 1/0 : $1) with linespoints pt 7 notitle

set title '0.0 invalid but treated as missing'
set datafile missing NaN
replot

unset multiplot

Output with 5.0.6: