I need to use gnuplot to plot wind direction values (y) against time (x) in a 2D plot using lines and points. This works fine if successive values are close together. If the values are eg separated by 250 degrees then I need to have a condition that checks the previous y value and does not draw a line joining the two points. This condition occurs when the wind dir is in the 280 degrees to 20 degrees sector and the plots are messy eg a north wind. AS the data is time dependent I cannot use polar plots except at a specific point in time. I need to show change in direction over time.
Basically the problem is:
plot y against x ; when (y2-y1)>= 180 then break/erase line joining successive points Can anyone give me an example of how to do this?
A sample from the data file is:
2014-06-16 16:00:00 0.000 990.081 0.001 0.001 0.001 0.001 0.002 0.001 11.868 308 002.54 292 004.46 00
2014-06-16 16:10:00 0.000 990.047 0.001 0.001 0.001 0.001 0.002 0.001 11.870 303 001.57 300 002.48 00
2014-06-16 16:20:00 0.000 990.014 0.001 0.001 0.001 0.001 0.002 0.001 11.961 334 001.04 314 002.07 00
2014-06-16 16:30:00 0.000 990.014 0.001 0.001 0.001 0.001 0.002 0.001 11.818 005 001.18 020 002.14 00
2014-06-16 16:40:00 0.000 990.014 0.001 0.001 0.001 0.001 0.002 0.001 11.725 332 001.14 337 002.26 00
and I want to plot column 12 vs time.