Forum Discussion
Sigma Formula for Carbon Estimation
Hi, could someone help me to transform the attached formula to Ms. Excel? I have been trying for over 3 days, but I got a different result from the reference document.
This Planvivo formula for baseline emission estimation
11 Replies
I would recommend collecting your data together in tabular form and, provided you are using Excel 365, perform calculations as array formulas using the structured references or defined names. I picked up some of the percentage issues from your later posts but have not worked through them in detail.
The data that you provide in the Excel file is insufficient.
The notation
implies that Drr, Apa and Grr are 3-dimensional arrays, and C and Csf are 1-dimensional arrays.
The sigma formula says that we sum Drr*Apa*(C-Cnf) + Grr*Apa*(C-Csf) for each i, j and k -- that is, for each cell identified by each i,j,k in Drr, Apa and Grr and by each corresponding i in C and Csf.
But you only provide only one value of each in columns B:D, to namely:
Drr i,j,k Peat swamp 0.20 Sec peat swamp 0.10 Riparian 1.70 Sec riparian 0.50 Grr i,j,k Peat swamp 0.13 Sec peat swamp - Riparian 0.01 Sec riparian - Apa i,j,k Peat swamp 30.00 Sec peat swamp 23.00 Riparian 713.00 Sec riparian 58.00 Ci Peat swamp 147.00 Sec peat swamp 147.00 Riparian 174.00 Sec riparian 174.00 Csfi Peat swamp 104.00 Sec peat swamp 104.00 Riparian 52.00 Sec riparian 52.00 If i goes from 1 to p, and j goes from 1 to q, and k goes from 1 to r, you need to provide p*q*r data for each of Drr, Apa and Grr and p data for each of C and Csf.
You might present Drr, Apa and Grr as p-by-q arrays of data repeated r times (a total of p*r rows). We can derive p from the size of C and Csf.
Otherwise, you need to tell us what p, q and r are.
Hi, I'm so sorry for this late reply. Well, I referred to the reference document which provides a table like below:
'Drr' and 'Grr' for each i,j,k
'Apa' value for each i,j,k
And the expected result should be like below (highlighted number):
What I tried in the excel file was to obtain that result. I also want to confirm, does the formula that I wrote in the file is correct?
According to this screenshot, the Drr and Grr values are percentages, so their values in your sample workbook are a factor 100 too large.
The value you want is the sum of the EBLs for the four forest types.
Your screenshots do not show the C, Cnf and Csf values, so I cannot check the outcome of your formula against that in the last screenshot.
Please attach a sample workbook with some data and the expected/desired result.
Hi HansVogelaar, thanks for your interest. I attached the example file. Thanks in Advance.
Thanks. I see the formula that you used.
Could you also tell us what the result should be? Perhaps that would provide a clue as to what would have to be changed.
