Can anyone reproduce my Chart error? Is this an Excel BUG?
Try plotting two lines in a XY-chart:
Each line should consist of 2 (X,Y) points. The X values of both lines should be set 0 and 5. The Y values should be calculated from other cells as: Y=S1*X+K1 and Y=S2*X+K2. Where S1 and S2 are the slopes and K1 and K2 are the interceptions. Set S1=1, S2=2, K1=0.001 and K2=0.001. Plot the lines in a XY-Chart. The next step is important: Set the X-Axes scaled from 0 to 0.1 and the Y-axes scaled from 0 to 0.1. The BUG: Now try changing S1 to S1=4. It is clear that something is wrong.The lines should have different slope but they have the same!! Go back, set S1=1. Try to chage the X value of 5 to something else, eg. 100.. whoaa.. strange result. There should have been no change in the chart, but suddently the chart shows a plot, where both slopes are same but not equal to what S1 and S2 where in the beginning! Can anyone help me to sort out the problem? I where trying to plot something with a small zoom on, but the result where WRONG! Is this a real bug? Does anyone get the same error? I've left an example on the net: http://home.tiscali.dk/phreaky/excel....chart.bug.xls -- Philip |
I tried it in XL 2000, XP, and 2003 with the following results:
1) The lines are not coincident, but series1 is also not right. Corresponding to y=0.1, you should see x=(0.1-K1)/S1=0.02475. The placement varies slightly among versions, but is in the vicinity of 0.035 2) Your results are reproduced in all three versions. I had previously observed that zooming in on the scale with smoothed lines could produce very inaccurate curves between points, but had not known that the problem also plagued straight connecting lines. Jerry Philip_plf wrote: Try plotting two lines in a XY-chart: Each line should consist of 2 (X,Y) points. The X values of both lines should be set 0 and 5. The Y values should be calculated from other cells as: Y=S1*X+K1 and Y=S2*X+K2. Where S1 and S2 are the slopes and K1 and K2 are the interceptions. Set S1=1, S2=2, K1=0.001 and K2=0.001. Plot the lines in a XY-Chart. The next step is important: Set the X-Axes scaled from 0 to 0.1 and the Y-axes scaled from 0 to 0.1. The BUG: Now try changing S1 to S1=4. It is clear that something is wrong.The lines should have different slope but they have the same!! Go back, set S1=1. Try to chage the X value of 5 to something else, eg. 100.. whoaa.. strange result. There should have been no change in the chart, but suddently the chart shows a plot, where both slopes are same but not equal to what S1 and S2 where in the beginning! Can anyone help me to sort out the problem? I where trying to plot something with a small zoom on, but the result where WRONG! Is this a real bug? Does anyone get the same error? I've left an example on the net: http://home.tiscali.dk/phreaky/excel....chart.bug.xls |
Tushar, This indeed is very strange. I played around with the sample file, and observed many quirky things. Enough to drive you nuts. My guess is that what's behind the strange behavior are the points that are actually far off the plot because of the manually set axis scales. When I developed the bezier code I noticed that excel tries to get clever when plotted points are off scale. Especially when smooth curves were turned on. I was expecting that "smooth curves" was involved here, as well. But it's not. Brian -- xlrotor ------------------------------------------------------------------------ Posted via http://www.mcse.ms ------------------------------------------------------------------------ View this thread: http://www.mcse.ms/message1411111.html |
Hi Brian,
Thanks for your comments. I guess this is yet another 'limit' on how well XL's charting module handles different user requirements. {g} -- Regards, Tushar Mehta www.tushar-mehta.com Excel, PowerPoint, and VBA add-ins, tutorials Custom MS Office productivity solutions In article , says... Tushar, This indeed is very strange. I played around with the sample file, and observed many quirky things. Enough to drive you nuts. My guess is that what's behind the strange behavior are the points that are actually far off the plot because of the manually set axis scales. When I developed the bezier code I noticed that excel tries to get clever when plotted points are off scale. Especially when smooth curves were turned on. I was expecting that "smooth curves" was involved here, as well. But it's not. Brian -- xlrotor ------------------------------------------------------------------------ Posted via http://www.mcse.ms ------------------------------------------------------------------------ View this thread: http://www.mcse.ms/message1411111.html |
Hi Tushar
Take also a look at the trendlines. The boxes which display the equations can be moved when the lines look okey. The boxes can for some reason not be moved when the lines are plotted wrong. They stay fixed in the upper right corner no matter what you do. Yep, some crappy code they put behind that drawing routine. Do you think MS will correct this problem in a future release? ----- Philip "Tushar Mehta" wrote: Hi Brian, Thanks for your comments. I guess this is yet another 'limit' on how well XL's charting module handles different user requirements. {g} -- Regards, Tushar Mehta www.tushar-mehta.com Excel, PowerPoint, and VBA add-ins, tutorials Custom MS Office productivity solutions In article , says... Tushar, This indeed is very strange. I played around with the sample file, and observed many quirky things. Enough to drive you nuts. My guess is that what's behind the strange behavior are the points that are actually far off the plot because of the manually set axis scales. When I developed the bezier code I noticed that excel tries to get clever when plotted points are off scale. Especially when smooth curves were turned on. I was expecting that "smooth curves" was involved here, as well. But it's not. Brian -- xlrotor ------------------------------------------------------------------------ Posted via http://www.mcse.ms ------------------------------------------------------------------------ View this thread: http://www.mcse.ms/message1411111.html |
Hi Philip,
Yes, I noted that problem with the trendline boxes in my first post. As to whether MS will fix the problem, my guess is "doubtful." After all, it hasn't fixed the problem introduced in XL2002 where one cannot format (delete) just one segment of a line chart. By comparison, this is so esoteric that I doubt it would even be considered. Then, of course, MS might just prove me wrong. {g} -- Regards, Tushar Mehta www.tushar-mehta.com Excel, PowerPoint, and VBA add-ins, tutorials Custom MS Office productivity solutions In article , says... Hi Tushar Take also a look at the trendlines. The boxes which display the equations can be moved when the lines look okey. The boxes can for some reason not be moved when the lines are plotted wrong. They stay fixed in the upper right corner no matter what you do. Yep, some crappy code they put behind that drawing routine. Do you think MS will correct this problem in a future release? ----- Philip "Tushar Mehta" wrote: Hi Brian, Thanks for your comments. I guess this is yet another 'limit' on how well XL's charting module handles different user requirements. {g} -- Regards, Tushar Mehta www.tushar-mehta.com Excel, PowerPoint, and VBA add-ins, tutorials Custom MS Office productivity solutions In article , says... Tushar, This indeed is very strange. I played around with the sample file, and observed many quirky things. Enough to drive you nuts. My guess is that what's behind the strange behavior are the points that are actually far off the plot because of the manually set axis scales. When I developed the bezier code I noticed that excel tries to get clever when plotted points are off scale. Especially when smooth curves were turned on. I was expecting that "smooth curves" was involved here, as well. But it's not. Brian -- xlrotor ------------------------------------------------------------------------ Posted via http://www.mcse.ms ------------------------------------------------------------------------ View this thread: http://www.mcse.ms/message1411111.html |
All times are GMT +1. The time now is 09:40 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
ExcelBanter.com