| T O P I C R E V I E W |
| Ginger_mao |
Posted - 06/06/2024 : 07:18:31 AM
Origin Ver. and Service Release (Select Help-->About Origin): OriginPro 2018 (64-bit) SR1
Operating System: Windows 10
Hello everyone,
I am using Origin to integrate the area under a curve. The problem is that selecting different "fit limits" in the "integration tab" causes the sign of the area value to change. For example, when I choose "interpolate to rectangle edge" or "interpolate/extrapolate to rectangle edge" the area is negative, but when I select "fit limits to data points," the integrated area becomes positive. My source data points on the X-axis are all integers (300-800)，and I chose the integration range from 400 to 780. Could someone help me to explain why this is happening? Does "fit limits" refer to the left and right integration boundaries on the X-axis? Could someone help me to clarify this?
  
Thank you so much!!! |
| 1 L A T E S T R E P L I E S (Newest First) |
| NicholasSupport |
Posted - 06/06/2024 : 4:48:39 PM
Hello Junqiu,
Thank you for reaching out about the unexpected integral output. A quick fix is change -Show Integrated Area to <Absolute>. This will give you only positive Area measurements.
But I would also like to know why Fit Limits To <Data Points> is giving you a negative result. However, when I went to recreate the situation in Origin I did not get a negative result. This indicates there is something causing the error in your project file.
In order to diagnose your project file, can you please share it with me? Specifically just the .opj file should be good. Also any raw data if you have that accessible.
Looking forward to figuring it out.
PS. You can press F1 with the integrate dialog window active, or press the  button in the Window Title bar, to be directed towards the documentation, which includes an explanation of each term in the dialog and more.
https://www.originlab.com/doc/Origin-Help/Gadget-Integration
Best,
Nicholas G.
nicholas@originlab.com
OriginLab Technical Support Team |
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