Dear David, Thank you for your reply. That was a good math lesson though :-). I believe your method would work too. Someone sent me a vi, just using the property node of the XY graph, there is a property called "Cursor.index" would directly output the index. So I guess LabVIEW has done all the hard work internally for us already.
Irene He www.geocities.com/irene_he www.hytekautomation.com ----- Original Message ----- From: "David Ferster" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, June 08, 2004 11:25 AM Subject: Re: Index of XY graph > What info are you starting from? Assuming you have the X and Y values > of the point whose index you want (call them A and B), then calculate > the squared distance of each point in the graph from (A,B) and find > the minimum (squared) distance. > > D = ((X-A)^2 + (Y-B)^2) > > Here, X and Y are 1-D arrays of the x and y values of all points in > the graph. D becomes is an array of distances squared. > > Now search D for 0's if you know A and B are exactly on a point. Or > use the Array Max and Min function if you just want to find the point > closest to A,B, for example, if (A,B) is the position of a cursor > placed near the point. In either case, you get an index of the point > in the graph closest to (A,B). > > David > > > > >Dear List, > >Does anyone know how to find out the index of a point > >in a XY graph? > >Thank you. > >Irene > > > >===== > >Irene He > > > >www.geocities.com/irene_he > >www.hytekautomation.com > > > -- > David Ferster > Actimetrics, Inc. > 1621 Elmwood Ave., Wilmette, IL 60091 > http://www.actimetrics.com > 847/922-2643 Phone > 847/589-8103 FAX > > >
