Plot day events from date and value in Gnuplot - gnuplot

I have data of this format:
2011-06-22 22:33:19 23 15
2011-06-23 09:46:13 12 79
2011-06-24 12:31:09 31 4
2011-06-24 17:34:10 7 2
2011-06-25 16:42:43 44 14
2011-06-25 20:26:52 54 9
2011-06-26 19:34:29 217 28
How can I create a histogram of daily activities with Gnuplot? By default, using these settings:
set xdata time
set timefmt "%Y-%m-%d %H:%M:%S"
set style data boxes
set grid
plot 'data' using 1:3 t "ins", \
'data' using 1:4 t 'dels'
the boxes will fit next to each other. But I would like to leave noneventful days at 0. Just like the Reputation graph here in StackOverflow behaves. If there's nothing on a given day, it should leave an empty place in the graph. If there's one event for one day, that box should be about the maximum width for one day. If there are more than one to given day, they all should be fit to that width.
Setting boxwidth is tricky because any value seem to give me 1-pixel wide "boxes".
Thanks kindly.

if I understand you correctly, then what you are trying to do is to my knowledge not possible with gnuplot. Or at least not in an easy way. And this is the reason why I think you'll have a hard time:
You cannot plot different box widths in a single plot. So trying to plot no box on an "non eventful" day and a single column on a day with one event will work just fine. Plotting multiple columns on one day where more than one event occurs in the same plot will fail because:
You cannot set different box sizes in the same plot
You need to offset the boxes on the same day according to the amount of events
There are ways to work around that problem for example plot two boxes of the same color next to each other to "simulate" a single box on one day and then make use of the smaller box width on days with two events. But this will very soon get pretty hairy and hard to maintain.
Maybe you want to think about using a different plot style? Take a look at histograms like here. Maybe one of the styles suites your data better. Or you could think about splitting your plot up into multiple plots?

Related

Excel - Plot average of two plots with inconsistent time (X) axis

I have managed to plot two different data sets on the same axis however, I'm also looking to plotting another line showing their average.
The main problem is that both data sets have different X (time) values so it's not possible to add an average column at the end and plot that. (See the highlighted row 22 for example, corresponding Time values are different)
Is there any way I can plot an average of two plots on the same axis?
One idea that might work is to place the values of both series, one above the other in two new columns, sort this new data according to time, smooth it, then plot the smoothed combined data. Alternatively, you could do the smoothing by simply plotting the new sorted series, adding a moving average trendline to it, then change the formatting of the new series so that it is no longer visible (but the trendline is). Something like this:
In the above picture, series 3 is the plot of the sorted aggregate data of series 1 and 2. If you change the formatting of series 3 so that there is no line, you get something like this:
For my relatively small mock data sets, the results are admittedly poor (it was based on just 25 data points in each series), but if you have a large amount of closely spaced data, and you play around with the moving average window size, you might get something acceptable. If not, you should probably just interpolate both datasets to obtain two consistent time series.

Plot data with quarterly tic marks

I am plotting data that is recorded on the last day of the 3rd, 6th, 9th, and 12th months of the year. I would like the tic marks to be at 03/09, 06/09, ...
After reading the documentation, I thought this could be done by saying
set xtics "03/09", 7889220
because there are about 7889220 seconds in three months. But rather than starting with March, 2009, the tic marks start on the next day, shown here (with the remaining part of the plot removed):
Is there a way to force the tic marks to be at end of months?
UPDATED:
The date format in the input file is mm/dd/yyyy, which I am reading with these commands:
set xdata time
set timefmt "%m/%d/%Y"
and I'm then doing this:
set format x "%m/%y"
set xrange ["03/31/2009":"12/31/2010"]
Discussion:
The Gnuplot behaviour when you use set format x "%m/%y" will be to place xtics at month boundaries since that really is what this command is asking Gnuplot to do.
To solve your problem there may be two posisble approaches that you can take here depending on how large your data set is.
Approach1:
If you do have time stamps in your data file one possibility is to just use the xtics directly for plotting (suitable if you have a large dataset)
So you do away with all the time commands in your script and just use
plot 'Mydata.dat' u 2:xtic(1) w points
Approach2:
The other option is to set custom xtics, however you will have to do this by hand and if you have a large dataset this might be cumbersome (suitable if the dataset has tens of points)
set xtics ("03/09" "03/31/2009", "06/09" "06/30/2009", "09/09" "09/30/2009", "12/09" "12/31/2009")
Will give you tics at the exact days you need them to be.
Assumption:
I assume that the first column in your file are the time stamps and second column are the data values. Below, I show a graph where I use the manual setting approach (Approach 2).
Result with dummy data:

Excel chart: on/off values with timestamp

I have 3 columns of data, eg:
http://i.stack.imgur.com/XjGmu.jpg
When Excel creates a line graph of this, the blue line is what i get.
This is not correct because the time stamp shows the time when something is switched on (255) or off (0) (could also be the current state eg 16:08). So I'd like a graph like this - see the red line (with a time-based X axis off course):
http://i.stack.imgur.com/vNvPk.jpg
Anyone can help? Thanks
As #Jon49 indicated, you need to plot additional data points--two y values for each x value: one to plot the point at y=255 and one to plot y=0.
If the time-span of the data is at least a few days, you can use a line chart. But in your case since the values are within a day, the scatter chart with straight lines is the only option due to the limitations of the scale units for line charts.
The key is the values need to be in the correct order. Each y=255 value needs to be followed by the next time-stamp's 255 value followed by it's 0 value, followed by the next time-stamp's 0 value:
Excel doesn't support this type of discrete value graph (at least not excel 2k3 that I am using); your best bet is to use a bar graph and then go into the settings and set the gap width down to zero.
Not sure what the best way is but I would automate what I describe below on how to do (unless this is a one time deal, then just brute force it):
Separate the 255s from the 0s. Make sure for every 0 time there is a corresponding 255 time. Take the zero times and put in a scatter plot then add a y-error bar and make the fixed value equal to 255. Format to how you like it.
Now for the 255s. Add those to the chart by pairs. Make the chart type for these pairs scatter plot with a line. Format how you would like them to look.
Let me know if that doesn't make sense to you.

gnuplot: display only the roots

Gnuplot, a great package ... I'm in love with it. But we can have our tiffs as well, as any couple :-)
This time, I wanted to simply plot the roots of an equation: say a quadratic to keep things simple. However, I only want two nice round dots appearing on the x-axis representing the point where the quadratic crosses the x-axis or y=0 axis. In other words the roots (when they are real that is).
I don't want to do this with datafile ... I want gnuplot to calculate the roots and plot them.
First off, my attempts: single points aren't really what gnuplot would have you plot, it likes a good wide range of values. Preferably filling up the whole width of your canvas.
It's possible to locate a rectangle at a certain coordinate on your plot, but I wanted a round point. Currently I'm chasing up how to do a tiny filled polygon at that point. I have tried the "samples" option bu it doesn't seem useful.
Also though about defining a dirac-delta function so that only one point would be highlighted (though two would be needed).
ANy suggestions welcome, thanks.
there is a way, but it takes just a little bit of fiddling
narrowness=1
set yrange [0:10]
set xrange [-10:10]
poly(x)=(x**2+3*x-2)
roots(x) =floor(narrowness*poly(x))?1/0:0
plot roots(x) w points pt 7
depending on the function and the range you will need to set the width differently. if you see too many circles increase the narrowness, if you see too few (aka. none) decrease the narrowness
Cheers!
/B2S
oh, and PS. to increase accuracy set samples to some higher value
And Alternatively if you happen to already know the roots, say r1(2,0) and r2(-1,0) then you can plot them using
plot '-' with points pt 7
2 0
-1 0
e
Not sure if this really helps, but if you can define a custom function to calculate the roots, gnuplot will display it.

Set Axis Tick Labels in gnuplot

My input to gnuplot looks something like this:
1:00am 1 10
1:00am 30 12
1:01am 60 18
1:01am 90 20
1:02am 120 21
...
The first column contains (what I'd like to be) the X-axis labels, while the second column contains the X-axis values. (In actual point of fact, I have one row per second, so many rows have '1:00am' as in the label column, then '1:01am', etc).
I can plot the values I care about using something like:
gnuplot> plot "my_data.txt" using 2:3 with lines
And I can set the X axis to have a tick (and label) every 30 minutes (which is 30 * 60 = 1800 seconds), but the label it uses is the X axis value (something like 3600 for one hour).
What I can't get is for the labels that show up under each tick to use the values from the first column. I can't even find anything that looks promising in the gnuplot manual. I've got to assume this is possible, I just don't know where to look.
Edit:
Progress, I've discovered the xticlabels() parameter to plot. The problem is that it seems to plot these labels for every xtic (that is, one per second in my data set), rather than at the intervals defined by set xtics.
Edit and Answer:
Turns out gnuplot has support for graphing time-series data. For the curious:
set timefmt "%H:%M:%S"
set xdata time
This causes the X axis data (once reformatted to match that pattern) to be interpreted as time-series data. This is then combined with
set xtics 3600
Formats the X axis as I described.
Sorry caught this late, but yes was to suggest set timefmt ... ; set xdata time. I always pass in my time format as %s but just as a common practice.

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