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#1
Posted to microsoft.public.excel.charting




Subtracting curves
Dear All
I am looking to subtract a baseline from graphs, but I have not found a method of subtracting curves in Excel. More specifically, I am looking to compensate for machine slack during compression testing, thus the baseline will be consistent from data set to data set. A colleague has designed a fairly complicated multi sheet workbook that interpolates the data ranges before graphing, but it has it's errors and is still not perfect. The best solution I have found so far is a program called FindGraph, but I am hoping to find a solution within Excel (ie: free!). Can anybody help? Many thanks in advance Andy 
#2




Answer: Subtracting curves
Hi Andy,
I can definitely help you with subtracting curves in Excel. Here are the steps you can follow:
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#3
Posted to microsoft.public.excel.charting




Subtracting curves
Are you offsetting all points of a series by the same amount? Then just add
or subtract the amount from each data value in the worksheet.  Jon  Jon Peltier, Microsoft Excel MVP Tutorials and Custom Solutions Peltier Technical Services, Inc.  http://PeltierTech.com _______ wrote in message ... Dear All I am looking to subtract a baseline from graphs, but I have not found a method of subtracting curves in Excel. More specifically, I am looking to compensate for machine slack during compression testing, thus the baseline will be consistent from data set to data set. A colleague has designed a fairly complicated multi sheet workbook that interpolates the data ranges before graphing, but it has it's errors and is still not perfect. The best solution I have found so far is a program called FindGraph, but I am hoping to find a solution within Excel (ie: free!). Can anybody help? Many thanks in advance Andy 
#4
Posted to microsoft.public.excel.charting




Subtracting curves
On Jun 25, 5:28*pm, "Jon Peltier"
wrote: Are you offsetting all points of a series by the same amount? Then just add or subtract the amount from each data value in the worksheet.  Jon  Jon Peltier, Microsoft Excel MVP Tutorials and Custom Solutions Peltier Technical Services, Inc. http://PeltierTech.com _______ wrote in message ... Dear All I am looking to subtract a baseline from graphs, but I have not found a method of subtracting curves in Excel. More specifically, I am looking to compensate for machine slack during compression testing, thus the baseline will be consistent from data set to data set. A colleague has designed a fairly complicated multi sheet workbook that interpolates the data ranges before graphing, but it has it's errors and is still not perfect. The best solution I have found so far is a program called FindGraph, but I am hoping to find a solution within Excel (ie: free!). Can anybody help? Many thanks in advance Andy Hide quoted text   Show quoted text  Hi Jon Unfortunately it's not as simple as that. While the data ranges covered are the same, the data points within the ranges do not match up across the ranges, hence the interpolation calculations being done at the moment. Andy 
#5
Posted to microsoft.public.excel.charting




Subtracting curves
I missed the interpolation remark. You could either fit both series to a
curve (trendline) and use the fitting parameters to determine the difference, or you could do the interpolation, wither using worksheet formulas or VBA.  Jon  Jon Peltier, Microsoft Excel MVP Tutorials and Custom Solutions Peltier Technical Services, Inc.  http://PeltierTech.com _______ wrote in message ... On Jun 25, 5:28 pm, "Jon Peltier" wrote: Are you offsetting all points of a series by the same amount? Then just add or subtract the amount from each data value in the worksheet.  Jon  Jon Peltier, Microsoft Excel MVP Tutorials and Custom Solutions Peltier Technical Services, Inc. http://PeltierTech.com _______ wrote in message ... Dear All I am looking to subtract a baseline from graphs, but I have not found a method of subtracting curves in Excel. More specifically, I am looking to compensate for machine slack during compression testing, thus the baseline will be consistent from data set to data set. A colleague has designed a fairly complicated multi sheet workbook that interpolates the data ranges before graphing, but it has it's errors and is still not perfect. The best solution I have found so far is a program called FindGraph, but I am hoping to find a solution within Excel (ie: free!). Can anybody help? Many thanks in advance Andy Hide quoted text   Show quoted text  Hi Jon Unfortunately it's not as simple as that. While the data ranges covered are the same, the data points within the ranges do not match up across the ranges, hence the interpolation calculations being done at the moment. Andy 
#7
Posted to microsoft.public.excel.charting




Subtracting curves
Dear Andy,
Don was absolutely right that the problem is in algebra. The second step, however, is the necessity of using more complicated algorithm that is not always free and at hand. What I would vividly agree with, is that VBA, as a kind of second stage development in Excel, can largely facilitate the €śsmall€ť work even in technical fields, provided the author is sufficiently familiar in programming. No simple application of only worksheet functions would help meaningful in this case, which should serve to routine (laboratory) work. I happen to have done the same task as you, two months ago; the only difference was that we perform flexural tests. The macro transfers a series (force vs. time) from a measuring text file into a new Excel worksheet, performs the conversion from time to deflection, and evaluates the slope forcedeflection (Young modulus) in the proper interval, etc. It really paid, because the procedure is lucid, anomalies can be easily recovered and treated, and numeric results be collected from individual lists to a summary. Macro normally doesnt require personnel educated in programming, as the deployment is on a key combination. The subtractive slack was here treated as a used defined function of a force value, obtained really by an interpolation over a calibration series. I would encourage you in offering some additional effort to remedy the program of your forerunner that seems well grounded, only needs debugging.  Petr Bezucha " wrote: On Jun 25, 5:28 pm, "Jon Peltier" wrote: Are you offsetting all points of a series by the same amount? Then just add or subtract the amount from each data value in the worksheet.  Jon  Jon Peltier, Microsoft Excel MVP Tutorials and Custom Solutions Peltier Technical Services, Inc. http://PeltierTech.com _______ wrote in message ... Dear All I am looking to subtract a baseline from graphs, but I have not found a method of subtracting curves in Excel. More specifically, I am looking to compensate for machine slack during compression testing, thus the baseline will be consistent from data set to data set. A colleague has designed a fairly complicated multi sheet workbook that interpolates the data ranges before graphing, but it has it's errors and is still not perfect. The best solution I have found so far is a program called FindGraph, but I am hoping to find a solution within Excel (ie: free!). Can anybody help? Many thanks in advance Andy Hide quoted text   Show quoted text  Hi Jon Unfortunately it's not as simple as that. While the data ranges covered are the same, the data points within the ranges do not match up across the ranges, hence the interpolation calculations being done at the moment. Andy 
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