An XY Plot question.

[needtolearnfast]

I am trying to plot on an xy plot the coordinates from a gps reciever as I recieve them and connect them with lines to show where the device has gone. I can do this, however, I was wondering if there was any way to change the color of the last point inserted or the last connected line drawn so I could see the latest update (this would be useful if the object was in a small clustered path). Is this at all possible in labview? I was thinking of plotting two plots on the graph, one with the last data point and one wthout behind that plot in a different color but this seems tedious and I can't get it to work right. Any help would be appreciated. Thanks.

[Odd_Modem]

You idea of using two plots is the way to do it.

Also, you can put a cursor on the last point as an indication.

[needtolearnfast]

Hi,

Thanks for the reply. So if I use two plots, how do I send the data in? I think I am messign up that part because they graph at different places. I have the set of old X coordinates in one array the set of new X coordinates in another and the same with Y. How would I wire these together to send into the XY plot? Also how do I make one grpah stay below another? Thanks for the help.

[needtolearnfast]

Another quick questioni about cursors, is it possible to have an arrow as a cursor and make it point in a certain direction given an angle measurement? FOr example if I give it 45 degrees it points 45 degress to the east of north? thanks.

[needtolearnfast]

Message Edited by needtolearnfast on 06-16-2005 06:53 AM

[Odd_Modem]

The bottom graph is plot zero, the top graph is plot 1. Draw plot 1 after you draw plot 0. The last plot drawn goes on top.

To get more than one plot I think you make an array of clusters. Pop up the help window and put the wiring tool on the graph terminal. The help window should then show some hints.

[Mark H]

To plot multiple plots on the XY graph you need to create & connect an "array of plots", a plot being either...

1. A cluster of two arrrays, one array being the x-coord's, the other array being the y-coords, or...

2. A cluster wrapped array of clusters of coordinate pair points.

There is a very good (albeit visually challenging) example in the LabVIEW examples>Fundamentals>Graphs and Charts>XY Graph.vi.

One plot will always sit on top of another - the precedence is determined by the plot order (plot 0, plot 1, etc), I can't remember off-hand which way around the order is, so just find out by trial and error.

Mark H.

[needtolearnfast]

Thanks a lot for all the help. Got it working.

[Mark H]

I doubt that you can change the form of the graphs bulit in cursors.

One option you could use though, would be to draw your own pointer on the graph by calculating/generating the coordinates/lines of the desired pointer and plotting these lines as if they were plot data.

I do something like this in one of my applications where I want some guidelines on an XY display (see attached picture) - my graphics are static so a little easier than a changing calculation, but easy when "done and dusted". The additional pointer graphics need to be bundled along with your plot data and sent to the graph terminal together.

Mark H.