![]() ![]() The legend is correct, and we have axis labels. Set ylabel "First Y Units" # label for the Y axis Set key autotitle columnhead # use the first line as title We'll also add a label to the X and Y axis: set datafile separator ',' The CSV file has column headers in the first line: "datetime","targetValue","measuredValue","secondYAxisValue", Legend has the plot commands, there is no grid and we're missing our second YĪxis. But the graph is still a bit hard to read. The basics are there, our two lines on the Y axis and Set format x "%H:%M:%S" # otherwise it will show only MM:SS Set timefmt "%Y-%m-%dT%H:%M:%S" # specify our time string format Set xdata time # tells gnuplot the x axis is time data Update your gnuplot file: set datafile separator ',' Let's tell gnuplot to use the first column as x axis datetime and ![]() The first column of our CSV file contains the date and time in an ISO8601įormat. Using the first column as x axis date time Run gnuplot, with -p to make the window persist: gnuplot -p example.gnuplot ![]() The first line tells gnuplot to use a comma instead of whitespace to seperate Plot plot.csv using 1:2 with lines, '' using 1:3 with lines Create a file namedĮxample.gnuplot in the same folder as your csv file and put the following in Let's start with the basic setup and command. Here is a picture of the finished result we're working towards: To append some data to the title of the graph. Not valid CSV, but we'll use that inside gnuplot The data is fromĪnother piece of software I've written and contains extra information, but that The article will go over the different topics step by step. You canįind my example CSV data at the bottom of this article. I'm using gnuplot 5.2 on Ubuntu 18.04, installed via the repository. With this referral link you'll get $100 credit for 60 days. You can also sponsor me by getting a Digital Ocean VPS. ![]() It means the world to me if you show your appreciation and you'll help pay the server costs. Go check it out!Ĭonsider sponsoring me on Github. I'm developing an open source monitoring app called Leaf Node Monitoring, for windows, linux & android. Please, if you found this content useful, consider a small donation using any of the options below: Recently I removed all Google Ads from this site due to their invasive tracking, as well as Google Analytics. The data in this article is masked, but that I've got an article published here where you can read howto make aīar-chart (histogram) with gnuplot. Styling (grid, line type, colour, thickness).Using multiple environment variables in gnuplot.Parsing the first column as a date/time.Such" in Excel to get a consistent result. Give me a configfile and command over "do this, then this and then such and Not only is it very extensible, it is also reproducable. My goto favorite tool for graphs andĬharts is gnuplot. LookingĪt a bunch of text is not the same as seeing things graphically, this particular You can find out more with the help samples command.Recently I had to do some testing which resulted in a lot of log data. The set samples command takes (optionally) two values, but the second value is only used for 3d plots. In the case of a sine curve, 100 is enough to see a smooth graph, but with a faster changing curve, we may need more. We can also see here that there is not much difference between the graph with 1000 points and 100 points. We can look at the individual points again (using a sampling rate of 100 as 1000 is too many to clearly see the points) Again, this is just a bunch of points connected by straight lines, but when there are a lot of these, it looks like a smooth continuous curve. Which produces a much nicer smooth curve. I usually set it to around 1000 with set samples 1000. Depending on how rapidly the function changes, higher values may be needed. The default is 100 (in 5.0 patch level 6). In order to improve this, I need to increase the sampling rate by using the set samples ? command. We can look at the individual points in order to see what is going on. Here the sampling rate is set pretty low. Suppose that I do plot sin(x) and see this: The number of points that it computes is user settable. Gnuplot doesn't really draw curves for functions - it actually computes the functions at multiple points and connects them with straight lines, similarly to what would happen if you were plotting a data file. You haven't shown what your particular functions are, but this is almost certainly a sampling problem. ![]()
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