Zooming a graph

I need to select a rectangular region of a graph with mouse dragging and then zoom that region. Can anyone tell me how to proceed? Thanks in advance...

What idea's do you have? Have you already tried something?
A solution would be to use a 3D API (e.g. Java3D) and just move the camera the appropriate bit. But there are also easy 2D solutions. But if it's part of larger application that already has drawing and selection functionaltites this can cause quite some problems.

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Questions about decimation and zoom in graphs

I am currently developing an application in which the size of the signals I have to display in different graphs is quite large (8 Mbs of DBLs, for example). I was thinking about reducing the amount of memory used when I found a document at National Instruments Developer Zone (http://zone.ni.com/devzone/conceptd.nsf/webmain/6A56C174EABA7BBD86256E58005D9712?opendocument), and inside that paper there was a paragrpah, "Fast Data Display with Decimation", that was perfectly suitable to me.
However, there is a drawback. If the user uses the zoom tools inside the Graph Palette to enlarge the decimated signal, and I do not take care of that situation in some way, doing so will result in an incorrect view since he will not be worki
ng with the original signal. Through events I am not able to know when the user has specifically zoomed the signal, not only touched the graph, so here are the questions: does anyone know a way to detect when the user has used the Graph Palette or the other items of the Waveform graph as the Scale Legend, for example? In general, is there a way that you can reduce the amount of points showed in a graph and still work with zooming tools without problems?
Thanks in advance and have a nice day,
spj

The things you say in your comment are right. In fact, that was what I had to do to fix the problem. Let me explain myself a little further.
I needed to reduce the memory, so I decimated the signal. To take care of the zoom bussiness, in my Diagram Block I put an event case to warn me when the mouse left the graph in order to do exactly what you have mentioned: with the original signal and the new limits, being aware of the x-multiplier, re-decimate the signal if necessary.
But that is when my problem arises. I am not able to distinguish when the user is really zooming the signal or merely touching the graph, without zooming anything. Now you can see the reason of my questions.
Thanks for your interest, Joe, and have a nice day,
spj

Zoom Radar Graph/Plot

Hello,
is there a way to zoom in/out in a radar plot. (http://zone.ni.com/reference/en-XX/help/371361J-01/lvpict/radar_plot/)
Thanks in advance!

as the output of this vi is a picture control, you can use the zoomfactor property-node:
"..\National Instruments\LabVIEW 2014\examples\Graphics and Sound\Picture Plots\Simple Radar Plot.vi"
♜♖ LabView 8.6 - LabView 2014 ♖♜

Adf Dvt bar graph zoom/scrolling to given zoom level

Hi,
I am developing a dashboard, where I need a functionality with bar graph, that will zoom bar graph at particular zoom level while loading.
Please help me, How can I pass zoom level to bar graph to zoom in at loading time?
Thanks,
Jassi

Thanks Vlad for response,
<dvt:barGraph id="barGraph" subType="BAR_VERT_STACK" shortDesc="Query Result Graph"
tabularData="#{demo.graphTabularDate}" seriesRolloverBehavior="RB_HIGHLIGHT"
animationOnDisplay="auto" animationOnDataChange="alphaFade"
dynamicResize="DYNAMIC_SIZE" imageFormat="AUTO" visualEffects="AUTO"
binding="#{demo.graph}">
<dvt:o1Axis scrolling="on" /> 
<dvt:legendArea scrolling="asNeeded" automaticPlacement="AP_NEVER" position="LAP_RIGHT" />
<dvt:o1TickLabel tickLabelSkipMode="TLS_AUTOMATIC"/>
</dvt:barGraph>

Disable Pinch to zoom in SAP dashboard mobile

Dear all,
I'm developing a dasbhoard with sap bi dashboard 4.1 sp1 for mobile device bi app 5.1.8
My customer asked me if it's possible to disable the Pinch to zoom in graph, when i view the dashboard in mobile app.
I don't think , but do you have any idea (also by sdk)?
thanks
viviana

Bugged me for ages as well. One thing that seems to work (hooray...)
1/ Install BetterTouchTool http://blog.boastr.net/?page_id=195
2/ In BTT select "Application Finder" and "Touchpad"
3/ Add new gesture twice, set one to Pinch In, the other to Pinch Out
4/ Keep the assigned action / shortcut empty [...or assign it to a script that says "Hooray... Not zooming" if you prefer ...]

Digital Waveform graph with a lot of samples

Hi,
I have to display in a Digital Waveform Graph a lot of data read from a file(2.000.000 of samples for 36 signals). If I read the file and I try to display all the data, the Vi became unusable. For example, to zoom a graph region, it may take 30-40 seconds, scroll is impossible ecc, ecc..
Apparently LV doesn't perform a decimation of points. In measurements studio 8, this problem doesn't exist...but I have to use LV 7.1..
any suggestion ?
At the moment I have developed a DLL in VC++ that perform a decimation of samples, but performance are not very good !
Thank you for any idea.
Regards.

Hi Garraty,
Excuse me but I have several questions for you.
1)     Have you tried some kind of incremental approach, starting from 1 waveform and increasing towards 36? Do you experience some kind of on/off degeneration between, les’s say, 34 and 35 waveforms?
2)     How can you decimate a digital pseudorandom sequence of 2M samples without loosing information?
3)     Is this 2M samples an unavoidable constraint for your application?. Actually, it seems very difficult to extract some kind of visual information from a pseudorandom pattern of this length?
Thank you very much.
Kind Regards
FiloP
FiloP
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
Richard P. Feynman

Updating graphs between two VIs

I have a VI (event-structure based) that generates and displays waveform chart. Due to lack of space on the main VI, I want the graph to be displayed onto another VI. Could anyone please help me with an example, how to implement this?
My attempt doesnot update the graph using sub-VI.
Thanks
Rajeev
RY
Solved!
Go to Solution.

A simple example is attached along this email. The subVI is invoked from the MainVI which attempts to zoom the graph, but it does not continuously update the graph data as in MainVI. Thanks
RY
Attachments:
MainVIGraph.vi ‏51 KB
SubVIGraph.vi ‏12 KB

Multi Y-scale zoom problem

I created two Y-scales on my XY Graph and attached one plot to each scale. The problem is that when i am trying to zoom the graph it changes both scales. I tried to set Active Scale before zooming but that didn' help.
Is it possible to zoom scales independently using Tools from Graph Palette?

Hi Jonni,
I have attached an example in LabVIEW 8, you can change your Y-Axis range to zoom in on individual plots.
Regards
JamesC
NIUK and Ireland
Attachments:
Use Axis range as zoom.vi ‏15 KB

Synchronizing 2 graphs / producer-consumer loop stuck

I have a pretty huge VI here, so I created a smaller one, which shows my problem.
First thing is, the user has to set some parameters, before the VI is running. So, I created a sequence with a while loop. If the user hits the button, the loop ends. That works pretty well.
In my huge VI I am doing data acquisition. The user hits the button in order to acquire data, checks the data and the data is saved when he hits the acquire button the next time.
Next thing is, I have two graphs. When the user zooms one graph the scale of the other should be updated automaticaly. Therefor I created a loop with a event structure in it. If the user hits the button in order to acquire the next set of date, the loop ends. So far so good, this works pretty good as well.
But now - if I zoom the graph before I hit the button in order to end the while loop, everything gets stuck. I don't know how to get rid of that behaviour.
Please do not suggest anything like getting rid of the producer/consumer loop, since I specifficaly need everything that is in the VI for a certain purpose.
If you need any additional information, please just ask. I hope my problem is described well enough so far.
Attachments:
zoomprob.vi ‏41 KB

thanks for the response,
the upper event structure will trigger the data acquisition process, so I don't want to have any time out value unless the user wants to start the acquisition process.
the lower event structure will take care of the state when the acquisition is done, but the user wants to examine the aquired data. Using a longer time out will not be a disadvantage, but I think it will not solve the problem alone.
At the moment everything works fine, if you use it how it is ment to be used. If you aquire data and then mess up with the graphs scale, everything is good. But if you try to manipulate the graph and then acquire data, it gets stuck. Apperently, that is not how it's ment to be used - but you know what users often do...
Unfortunately the highlight execution is of no particular use. If I turn it on and manipulate the graphs scale, the vi gets stuck, but no specific process is shown in the code. Apperently it is waiting for a event, but it isn't triggered. So, beeing able to disable an event structure and enabling it later would solve the problem, for example.... I haven't found any solution for dealing with that, unfortunately...

Set scale values when zoom out

Hi!
I have a XY Graph and I want it to have three different scale ranges depending on a case structure. So, for example, if it's case 1, I have the xy graph X.minimum = 1,234 and xy graph X.maximum = 10,789 and so on.
I want to be able to zoom the graph but then when I zoom out to see all the points, I want it to have the same range I defined. I have the autoscale turned off and when I do the zoom out, it shows me different minumum and maximum values....
Any help?

Hello Zephirus,
When you ask a zoom out, write the scale value that you define, using a property node. To get it, right click on the XY graphe terminal, in the diagram, then select Create >> Property node >> X (or Y) Scale >> Range then All elements, or just the elements you need to coerce.
Let me know you progression,
Message Edité par Mathieu R. le 11-14-2006 02:52 PM
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Mathieu R.
  CTD - Certified TestStand Developer / Développeur TestStand Certifié
  CLAD - Certified LabVIEW Associate Developer
Attachments:
PropScaleXY.JPG ‏7 KB

How to using ni:Graph Control draw more than 500000 points

this is my test code:
ChartCollection<DateTime, double> chartCollection  = new ChartCollection<DateTime, double>();
chartCollection.Append(dateTimeList, doubleList); //dateTimeList and doubleList has 500000 points
graph.DataSource = chartCollection ;
but a System.OutOfMemoryException  throwed in mscorlib.dll when I zoom the graph.

Based on the data types involved, I believe you are hitting the same issue as the question WPF graph AxisDateTime crash. To avoid the crash, change the Mode of the MajorDivisions and MinorDivisions of your axes. For example, the XAML below reduces the number of major divisions to three and hides the minor divisions:
    <ni:AxisDateTime Orientation="Horizontal" MinorDivisions="{x:Null}">
         <ni:AxisDateTime.MajorDivisions>
             <ni:RangeLabeledDivisions Mode="Count: 3" />
         </ni:AxisDateTime.MajorDivisions>
     </ni:AxisDateTime>
~ Paul H

Acquisition problem

Hi i'm currently using the NI USB 6259 BNC to read a voltage signal from a vibration sensors to a frecuency of 8Khz, i'm testing the program with a signal generator and a sine wave of 7Khz but whem I do a zoom of the signal in the grap. The wave isn't show perfectly i'm using the daq assistent in continuos mode with a rate of 32k and samples to read of 16k, someone knows how to fix that problem.
This is my code for 1 channel only but i will use it for 6 channels only adding more channels in the assistant.
It is urgent.
Attachments:
Modulo I 1 Canal - BLACK ED.vi ‏146 KB

the fault is that when I zoom the graph the wave doesn´t look like the original wave before the acquisition. these are the photos of the fault.
Attachments:
DSC04203.JPG ‏2338 KB
DSC04199.JPG ‏2371 KB

Zoom bar error in OBIEE11g(version:11.1.1.5.0) in Graph view reports.

HI,
we are getting the following error message while trying to perform Zoom in or out option in the graph view reports in IE8 browser .
Error message:An error occured while processing your request.Please contact your site administrator.
Note:Its working fine in Mozilla Firefox browser,But my client using IE8 browser, Hence the issue .
Please help me on this ASAP..
Thanks & Best regards,
Purna

I have exported ODBC path manually.
export ODBCINI=$ORACLE_INSTANCE/bifoundation/OracleBIApplication/$ORACLE_BI_APPLICATION/setup/odbc.iniAnd then executed the nqcmd command. Now I am getting the different error.
Oracle BI ODBC Client
Copyright (c) 1997-2011 Oracle Corporation, All rights reserved
Initialize client environment failed, possibly caused by incomplete installation
[nQSError: 47001] Invalid Oracle BI Bin directory:
/oracle/home/bifoundation/server/bin.
Initialize client environment failed, possibly caused by incomplete installation
[nQSError: 47001] Invalid Oracle BI Bin directory:
/oracle/home/bifoundation/server/bin.
[0][State: IM004] [DataDirect][ODBC lib] Driver's SQLAllocHandle on SQL_HANDLE_ENV failed Connect open failed

Has anyone "zoomed in" on a portion of a waveform graph?

Has anyone ever used two cursors to zoom in on a portion of a waveform graph?
I've seen that newer Oscilloscopes offer features to do this both horizontally and vertically.
See the attached jpg for an example of what I'm trying to do. It is from Google Finance. Notice the area circled in red. The two cursors define the portion of the waveform to be displayed on the main graph. There is also a scrollbar beneath them which allows the user to quickly move the zoomed-in area across the graph- I would love to have that functionality on the LabVIEW graphs.
My first thought is that I can do this using mostly property nodes. Not sure on vertical zooming scrolling the horizontal zoom- I'm thinking maybe this would best be done using scrollbars which are not part of the graph itself.
Any ideas or comments?
Thanks,
Dave
Attachments:
deleteme.jpg ‏38 KB

Cursor position is available in Labview via a property node. You can also set about every chart property with property nodes. I have used this many times. Here is a trick. If you have two cursors, Make separate arrays of the x and y positions. Then use the "Array max&min" to sort them. This will make your program independent of the cursor sequence.
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

XY graph zoom problem

Hello,
There is a issue when you zoom in using a XY graph. Say you have a two points one at 0,0 and another at 10000,10. If you zoom in to say point 5000,5 the centre point the line will be way off nowhere near where it should be crossing. I was wondering if anyone knows a fix for this problem?
Thanks

I agree that this does not look right, but is probably due to limitations in the math used. Once you zoom into the area of iterest, the position of the line actually changes as a function of zoom level. (for example, the 5000 crossing of the line is at 5.00, then at 5.015, then at 5.16). I am sure the accuracy it could be improved, but maybe at a cost of performance.
It should definitely be investigated.
LabVIEW Champion . Do more with less code and in less time .

Zooming a graph

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