Well being a surveyor for 35 yrs I just had to know the true volume vs. the Internet's pool volume calculators.
I ended up with 10 different sections that I broke out including the steps and there volume.
Did the calcs and ended up with 2,000 gal less then pool calculators estimate.
I also wonder if these pool calculators just assumed you have vertical walls or do they take in account that most pool walls slope. Now I Know.
Some pools like round above ground are fine. But if you have a ig pool with sloping sides no way can you get the correct volume with 4 measurements.