
I was looking out on the Internet for a volume calculation to test QSOnscreen against and this one from the wikipedia external links was a suitable candidate. This is a direct link to the same example. Here's the QSOnscreen image and data which I created as a test. Unzip the two files into the same directory and double click the .qso file if you want to run the calculation in QSOnscreen yourself or you can see the final result here now that QSOnscreen has it's own printscreen facility. You can see that QSOnscreen comes up with 567m3 as the total earthworks fill whereas the Internet example is showing 623m3. WHAT!! There must be some mistake! and there is...but it's not with QSOnscreen. A quick check through the Simpson's Rule example figures shows an error in the calculations of the 2x column resulting in a total earthfilling volume of 341.425 x (5/3) = 569m3 Now that's more like it! A variance of just 2m3 between the two calculations. Just goes to show that not everything out there on the Internet is 100% accurate. Here's a spreadsheet with the CORRECT Simpson's Rule calculations and also a comparison with a manual calculation using the Trapezoidal Rule which comes out at 568m3 The good people at Wikipedia have now flagged up the error in their external link which remains a good working example of the application of Simpson's Rule to volume calculation once the calculation error has been noted. For more example QSOnscreen projects and comparisons with similar programs look here 
Send mail to
with questions or comments about this web site.
