I need the precise sum of areas for a polygon layer, where I have the area values in an attribute. When I use the Statistical Summary window it shows the sum in exponential notation:

Statistic   Value
Count       232
Sum         6.68428e+06
Mean        28811.6
Median      19993.4

At first I thought it was a display issue related to column width, but no. And I hoped that copy-paste might reveal the true value, but also no.

The Area values have 11 decimal places. Can I get the sum to be the same degree of precision as the original data? (I don't actually need 11dp, but I would like to choose for myself the precision to report, rather than have QGIS dictate!)

There is an excellent answer to a previous related question (Summing data from column in Attribute table) but it does not mention this issue. I am using QGIS 3.10.10.

  • 3
    I guess you mean "how do I format the numbers with specified decimal places". The mean suggests original data is 1 decimal place in numbers that have whole 5 digits. Hence the decimal place is probably irrelevant anyway in terms of the precision of the measuring system. It is at best +/- 0.04%. By the way, there is nothing "imprecise" about the exponential notation. it just means 6,684,280. I cannot imagine when one or more decimal places would add value to a number of this magnitude but perhaps there are in some disciplines (it is +/- 0.00001 %). – Leigh Bettenay Jan 15 at 23:16
  • I agree that the error is small and ultimately inconsequential. I am trying to match answers (for a student exercise) between both Arc and Q, as we have students using both. Arc gives me the sum in the same format as the individual values (11dp). – ermintrude75 Jan 16 at 10:33
  • 1
    (The student exercise does go on to discuss precision, which is why it's useful to start with an excess of digits purely for illustrative purposes!) – ermintrude75 Jan 16 at 10:43

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