the best way to make a nice POLAR plot in LV

[pawel]

Hello All
What is the best way to plot a polar plot? I know there is a polar plot in LV, but it is not so flexible as a normal plots. Also interaction with this plot is rather poor since it is a picture.
Is it possible to use some ActiveX Polar Ploter, if such exists? And what do you think of using for this ex. HiQ?

regards
Pawel

[Greg_McKaskle2]

If you have an installed component that will draw a polar plot, you should be able to use it in LV. I'm not sure if HiQ actually had a polar plot, and I'm pretty sure it wasn't an ActiveX control.

You haven't said what it is that you want in the plot, but the source code for the picture version is included. If you describe it, the coding change might be pretty simple.

Greg McKaskle

[pawel]

Hello

I have the polar plot for picture control and I do not like it. The main problem is, as far as I see it, that the picture can not return the "handlers" to the plots I put to the picture. In other words, I can not plot two polar curves and distuinguish which one is which after I plot them. That only sounds silly, but it has a consequences. Raster plot is something I would like to avoid.

I was thinking about some toolbox to use a standard XY Graph to visualize polar plots and also to support the interaction with the curves and cursors. Do you know if such a thing exists?

regards
Pawel

[Jeremy Braden]

As a workaround, why do you not overlay several picture displays and color their background transparent? This way you can plot one plot per control yet the user will see just one plot.

[Greg_McKaskle2]

If you open the diagram to the polar plot, you will see that there are just a few functions on the diagram. The Plot Polar Data function can be replicated to put as many plots on as you need. You can decide whether the data comes in as a cluster, a 2D array, or two imputs.

If you want cursors, this does get more complicated, and I have seen subVIs to map data to polar and draw grids. They perform pretty well, but I don't have any of them at hand.

As for raster plots, to me this term means that the lines are drawn with discrete pixels, and it is a pretty rare computer monitor that doesn't operate on pixels. If you can be more precise about what you don't like, I can give better advice.

Greg McKaskle

[pawel]

Hello Greg

My point is that the current PolarPlot is a raster image, which means that for a processing you need to use a raster functions. I would rather have a vectorial plot to play with the plots. That is what XY plot can offer. I think I have found out the solution. The polar grid I will make as a raster image, because a lot of lines needs to be plotted. Whereas the actual plot I will make in XY graph with a transparent background.

Thanks for discussion.

Pawel

[pawel]

Hello Jeremy

That is more less what I did, but I overlay one picure with a XY graph.

kind regards
Pawel

[Greg_McKaskle2]

I thought that was what you meant by raster. Both the XY graph and polar plot work by taking points, one as (X,Y), and the other as (r, theta) and drawing lines between them. The lines are then rendered, or rasterized on the device currently being drawn to. For screens, it will be about 100dpi rasterization, and for printers 600 or so.

Anyway, both work the same, but the XY graph makes it easy to type into the scales or use a tool to zoom and see more resolution. If you have a way to enter in the different scale parameters and do a little math, the polar can do the same.

Anyway, we now understand each other, and you can use the XY graph if you draw a plot that looks like the grid, or you can make the polar plot z
oom, if that is what you want.

Greg McKaskle

[pawel]

Hello Greg

I am still not sure if we understand each other :).
I think we are talking about the same thing, but on different aspects.
I agree that polar plot (picture) and XY graph (waveform) can render whatever I asked it for. But imagine you want to do some processing on the data. When you read polar plot you will get a bitmap. That is you will not be able to distuingish between two lines you have ploted. That will be just a pixel with some value. On the other hand when you read a XY graph you will get a vectorial quantity with [X,Y] coordinated defined.
Of course, you can buffer the data you sent to polar plot and make a processing on them, I agree, but in some cases (like user interaction) some tasks could be muc
h more difficult to do on polar plot. But probably I am talking obvious things, which I need not to tell you :).

kind regards
Pawel

[pawel]

Hi Greg again
I hope you will rad this message, though it is written after some time we have finished our converstion.
In previous post, you write that the polar plot will render my plot depending on the device it is sending the plot to. You give an example that if my device is a printer, the polar will render plot with 600dpi resolution.
That would work for me very well, but I need to ask you how make my printer the device that polar plot will write to.
For now I can print my polar on screen and then print the front pannel (good resolution), or save the picture to graphic file and print fron report or etc (poor resolution).
In case I could render the image directly on the printer I would obtain the best quality what
so ever, but I do not know how to make my printer a output device for a polar plot.

kind regards
Pawel