Plotting error bars in XY graph?

[Tawcan]

Hi new here. Not too sure if this is the right forum to post this if it isn't I'm sorry. :headbang:

I'm currently using Labview 6.1 and modifying a program. The part I'm working on right now basically takes various data readings, find the averages, and then plot these points on the XY graph.

Now it would be nice to plot the standard deviation on the graph too but I am not sure how to do that. I tried searching on the web but haven't been able to find anything. Is this doable in Labview? If so could someone teach/show me how?

THANK YOU!!!

[bogdani]

Hi

Few years ago I had the same problem. Then I found this: Plotting Error Bars in LabVIEW

It's working.

Bogdan

[Norm Kirchner]

Now here's something interesting/BUG.

I was trying to find an easier way than having about 100 plots to accomplish this.

I was thinking about making 1 plot of bar graph type of the upper limits and then filling it to another plot of the lower limits.

But alas, if you try to fill a bar graph to another graph (instead of to 0,+inf or -inf) it fills the whole area between the graphs.

BOOOO

Anyone know a way around this "Feature"

See attachment

Download File:post-208-1116868101.vi

[Kurt Friday]

You can use NaN to effectively lift the pen from the plot and hence plot what appears to be separate vertical lines. The attached code demonstrates generating error bar plot given a set of X, Y and Error values.

Download File:post-1058-1116913680.zip

[Norm Kirchner]

Nicely done SciWare!!!

I knew that there must be a more elegant way.

And a nice little bit of info about the NAN and lifting the pen effect.

:thumbup: way cool

[Tawcan]

Thanx got the error bars to work!

[oskarbosch]

Kind of late in this post. Just needed error graphs and came across this example. Made me think.

Made a modified version of the graph. The sample is creating many, many plots. Giving all kinds of colors.... Changed it to have just one graph, with each point made into 4 points.

1: Original point Xorg, Yorg

2: Xorg, Y+error

3: Xorg, Y-error

4: Xorg, Yorg.

Selecting the point style to be the cross (+), it shows very nicely. :thumbup:

Another approach (as mentioned above) would be two graphs. Original data, and the error bars using the points:

1: Xorg, Y+error

2: Xorg, Y-error

3: Xorg, NaN

This gives just an error graph and would allow you to give it a different color (and point style) than the actual data. Can be useful (just not what a collegue here needed).

Thanks for the idea's though.

Oskar